Devonian

@article{openalexw2726120922,
    author = "Swartz, Frank M.",
    title = "Revision of the Primitiidae and Beyrichiidae, with new Ostracoda from the lower Devonian of Pennsylvania",
    year = "1936",
    journal = "Journal of Paleontology",
    url = "https://openalex.org/W2726120922",
    openalex = "W2726120922"
}

@techreport{swartz1945zonal4,
    author = "Swartz, F. M",
    title = "Zonal Ostracoda of the Lower Devonian in New York and Pennsylvania (abstract)",
    year = "1945",
    howpublished = "Geological Society of America Bulletin, v. 56, p. 1204-1205",
    note = "talkorigins\_source = {true}; raw\_reference = {Swartz, F. M., 1945, Zonal Ostracoda of the Lower Devonian in New York and Pennsylvania (abstract): Geological Society of America Bulletin, v. 56, p. 1204-1205.}"
}

@article{doi10113000167606196778609jitapo20co2,
    author = "Nickelsen, Richard P. and HOUGH, VAN NESS D.",
    title = "Jointing in the Appalachian Plateau of Pennsylvania",
    year = "1967",
    journal = "Geological Society of America Bulletin",
    url = "https://doi.org/10.1130/0016-7606(1967)78[609:jitapo]2.0.co;2",
    doi = "10.1130/0016-7606(1967)78[609:jitapo]2.0.co;2",
    openalex = "W2033517418"
}

@misc{klapper1967evolutionary2,
    author = "Klapper, G. and Ziegler, W",
    title = "Evolutionary development of the Icriodus latericresens group (Conodonta) in the Devonian of Europe and North America",
    year = "1967",
    howpublished = "Palaeontographica, Series A, v. 127, p. 68-83",
    note = "talkorigins\_source = {true}; raw\_reference = {Klapper, G., and Ziegler, W., 1967, Evolutionary development of the Icriodus latericresens group (Conodonta) in the Devonian of Europe and North America: Palaeontographica, Series A, v. 127, p. 68-83.}"
}

@techreport{walker1971nondeltaic5,
    author = "Walker, R. G",
    title = "Nondeltaic depositional environments in the Catskill clastic wedge (Upper Devonian) of central Pennsylvania",
    year = "1971",
    howpublished = "Geological Society of America Bulletin, v. 82, p. 1305-1326",
    note = "talkorigins\_source = {true}; raw\_reference = {Walker, R. G., 1971, Nondeltaic depositional environments in the Catskill clastic wedge (Upper Devonian) of central Pennsylvania: Geological Society of America Bulletin, v. 82, p. 1305-1326.}"
}

@article{doi101038270304a0,
    author = "Irving, E.",
    title = "Drift of the major continental blocks since the Devonian",
    year = "1977",
    journal = "Nature",
    url = "https://doi.org/10.1038/270304a0",
    doi = "10.1038/270304a0",
    openalex = "W1983530480",
    references = "doi1010160040195175900141, doi101038225139a0, doi101080037362451938105591187, doi101098rspa19530064, doi101098rsta19650020, doi101111j1365246x1963tb07084x, doi101111j1365246x1971tb02190x, doi101130001676061970812553tuatmo20co2, doi10113000167606197283619ssitna20co2, doi1023071796560"
}

Four new species of dipnoan fishes (lungfishes) are described from the Frasnian of Western Australia: Griphognathus whitei, Chirodipterus australis, C. paddyensis and Holodipterus gogoensis. These genera were originally set up for European species, and hitherto have not been known from the Southern Hemisphere. A detailed account of head structure is given for the first time in fossil dipnoans in a series of accounts of regional anatomy, each accompanied by a brief discussion. Interpretations in this part of the paper are based explicitly on the prior assumption that dipnoans are most closely related to crossopterygians, i.e. to choanates plus actinistians (coelacanths). The consequences of this assumption are exposed to criticism. The Gogo genera are divergently specialized. Griphognathus has an elongated snout and a primitive dentition of tooth-ridges and buccal denticles. Chirodipterus has a short, blunt snout, a relatively short prepineal length and highly organized entopterygoid and prearticular tooth-plates. The two Gogo species differ principally in tooth-plate morphology. Holodipterus has a moderately elongated, broad snout and a dentition of knob-like teeth and buccal denticles. All four Gogo dipnoans have an ossified neurocranium, meckelian cartilage, hyoid arch and gill-skeleton, with both perichondral and endochondral bone. The quadrate is fused to the neurocranium by means of basal, ascending and otic processes, and there is a lateral occipital fissure contiguous with the reduced, posteriorly-placed, ventral otic fissure. There are no visible sutures or ossification centres in the neurocranium. Griphognathus is exceptional in having at least one vertebral centrum included in the neurocranium and a pit for the attachment of the dorsal longitudinal ligament; the other forms have a large notochordal canal. The upper part of the otic region in all species bears lateral, dorsolateral, adlateral and median cristae, which raise the dermal skull-roof above the surface of the neurocranium to leave wide passages for divisions of the adductor mandibulae muscles. The lateral face of the otic region bears an extensive hyomandibular facet which straddles the jugular canal. An adjacent, unossified area may be the site of Pinkus' organ (the spiracular sense organ). More ventrally, on the edge of the quadrate, there is a prominent bulge for the hyosuspensory ligament; and on the ventral surface of the neurocranium there is an articulation area for the first gill-arch, which has previously been interpreted as the foramen for a hypothetical R. ventralis IX. The jugular groove is partly closed in by a prominent adotic process in Griphognathus and a small adotic eminence is present in the same position in other species. The cavum epiptericum, and the passages for all the major nerves and vessels in all the species can be interpreted by comparison with Recent dipnoans, particularly Neoceratodus. However, there is no clear passage for the efferent pseudobranchial artery in Griphognathus; the posterior cerebral vein of Holodipterus appears to have formed a network of vessels which passed out through several foramina in the otic region, rather than through the vagus foramen; and there is a network of canals draining into the orbit from the base of the cranium in Chirodipterus and Holodipterus, otherwise known only in Dipnorhynchus. There is an extensive supraotic cavity in the Gogo dipnoans, as in Eusthenopteron, with an anterior paired and a posterior median division. This cavity housed extensive endolymphatic sacs. The paired endolymphatic duct opened on the surface of the neurocranium and extended up to the dermal skull-roof in a groove on the dorsolateral crista. It may have opened to the outside in at least some specimens of Griphognathus. The nasal cavities are open ventrally and there is a broad internasal septum as in other Devonian dipnoans; the anterior nasal opening notches the upper lip. Griphognathus is unique in having the nasal cavity partly floored, and in having a well-defined posterior nasal opening between dermal bones of the palate. The dermal bones of the palate and ventral surface of the neurocranium include a parasphenoid with a long posterior stem and closed buccohypophysial canal, entopterygoid, dermopalatines and vomer. A posterior pit between the parasphenoid and neurocranium received the aortic ligament in Griphognathus. There are several dermopalatines in Griphognathus and Holodipterus, but only one in Chirodipterus. There is also an ectopterygoid in Griphognathus and possibly in Holodipterus. The vomer is a median element in Chirodipterus and Holodipterus; its presence in Griphognathus is unconfirmed. Thickenings on the dermal upper lip may indicate the inclusion of a premaxilla in the dermal snout. A vestigial maxilla may be present in Griphognathus in the form of tooth-plates lying in the lateral wall of the nasal cavity. The lower jaw ramus is elongated in Griphognathus and there is a short retroarticular process; but the number of dermal bones is reduced from the primitive dipnoan number of seven, and the infradentary series is represented by only two main elements. The adductor pit is closed, indicating that the muscles inserted on the lateral face ot the angular. Both Chirodipterus and Holodipterus retain the primitive number of dermal bones. The jaw of Chirodipterus is similar to that of Dipterus valenciennesi but it is relatively broader. That of Holodipterus is exceptionally powerful. Both of these Gogo forms have a wide-open adductor pit. Previous approaches to the interpretation of dermal bones of the skull-roof and cheek of Devonian dipnoans are reviewed critically to diminish the risk of reaching false phylogenetic conclusions. The lateral-lines and bone patterns of Griphognathus and Chirodipterus are normal for these sorts of dipnoans; those of Holodipterus are less well known but present no unusual features. The operculo-gular and submandibular series in all Gogo genera conform to the expected pattern: Chirodipterus australis may be exceptional in having only one subopercular bone. A fine dermal ornament is present in Griphognathus and Holodipterus, both of which lack cosmine on the head. Chirodipterus, however, is a cosmine-bearing dipnoan, and this tissue displays all the qualities previously recorded in dipterids, including complete resorption of the outer layers of the dermal snout in some specimens. In all genera, the lateral-lines open by small pores and there are richly developed rostral and symphysial tubuli. The hyoid and branchial arches are known in all species, but they are most completely preserved in Griphognathus. They answer closely to those of Neoceratodus. There is a hyomandibula, accessory element (in one specimen only), large ceratohyal and hypohyal. The gill-arches appear to lack pharyngobranchials; they clearly lack hypobranchials. The basi-branchial series comprises a large anterior and a small posterior element, the first of which is co-ossified with an elongated basihyal (“sublingual rod”) in Griphognathus. There is no sign of an ossified basihyal in the other forms. In Griphognathus alone, there is a urohyal which articulates with the basibranchial series, and paired anterior and posterior basibranchial tooth-plates. The principal conclusions about the interrelationships of dipnoans are that previous systems are grossly unparsimonious, but that it is not possible to replace them with a satisfactory phylogenetic scheme. The most primitive species is Dipnorhynchus sussmilchi. A series of derived characters can be recognized at more advanced levels, of which the most important involves the closure of the pineal foramen, changes in the dermal bone and lateral-line patterns of the skull-roof, modifications in the parasphenoid, and the origin and development of highly organized entopterygoid and prearticular tooth-plates. These changes permit a rudimentary cladogram to be constructed, but this is, perforce, reminiscent of an anagenetic analysis. Many dipnoans cannot be classified in a phylogenetic scheme, including Chirodipterus and Holodipterus. Other conclusions are that Griphognathus is a rhynchodipterid, and therefore most closely related to Rhynchodipterus and Soederberghia; dipterids, in the accepted sense (including Dipterus valenciennesi, Rhinodipterus and Chirodipterus), probably form a grade group of unspecialized, cosmine-bearing Devonian dipnoans; and that Neoceratodus and lepidosirenids are more closely related to each other than they are to Ceratodus and Triassic forms, or to gnathorhizids. The principal broader phylogenetic conclusions concern the interrelationships of sarcoptery-gians, i.e. dipnoans, actinistians and choanates. The teleostome status of dipnoans is corroborated by a number of new observations, including the cranial fissure, supraotic cavity, urohyal, basibranchial tooth-plates and aortic ligament. Sarcopterygians are assumed to be the collateral descendants (sister group) of actinopterygians, and Westoll's hypothesis that the intracranial joint is a primitive sarcopterygian character is upheld, against the author's previous opinion. Other sarcopterygian specializations are found in the general form of the otic and occipital region, the extensive hyomandibular facet(s) and the adotic process. The intracranial joint is secondarily absent in dipnoans, but these fishes are more closely related to choanates than they are to actinistians by several specializations, including the presence of cosmine, submandibular bones and a highly-differentiated supraotic cavity. The first two of these specializations are also found in onychodontids, which may therefore be choanates.

@article{doi101111j109636421977tb01031x,
    author = "Miles, R. S.",
    title = "Dipnoan (lungfish) skulls and the relationships of the group: a study based on new species from the Devonian of Australia",
    year = "1977",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Four new species of dipnoan fishes (lungfishes) are described from the Frasnian of Western Australia: Griphognathus whitei, Chirodipterus australis, C. paddyensis and Holodipterus gogoensis. These genera were originally set up for European species, and hitherto have not been known from the Southern Hemisphere. A detailed account of head structure is given for the first time in fossil dipnoans in a series of accounts of regional anatomy, each accompanied by a brief discussion. Interpretations in this part of the paper are based explicitly on the prior assumption that dipnoans are most closely related to crossopterygians, i.e. to choanates plus actinistians (coelacanths). The consequences of this assumption are exposed to criticism. The Gogo genera are divergently specialized. Griphognathus has an elongated snout and a primitive dentition of tooth-ridges and buccal denticles. Chirodipterus has a short, blunt snout, a relatively short prepineal length and highly organized entopterygoid and prearticular tooth-plates. The two Gogo species differ principally in tooth-plate morphology. Holodipterus has a moderately elongated, broad snout and a dentition of knob-like teeth and buccal denticles. All four Gogo dipnoans have an ossified neurocranium, meckelian cartilage, hyoid arch and gill-skeleton, with both perichondral and endochondral bone. The quadrate is fused to the neurocranium by means of basal, ascending and otic processes, and there is a lateral occipital fissure contiguous with the reduced, posteriorly-placed, ventral otic fissure. There are no visible sutures or ossification centres in the neurocranium. Griphognathus is exceptional in having at least one vertebral centrum included in the neurocranium and a pit for the attachment of the dorsal longitudinal ligament; the other forms have a large notochordal canal. The upper part of the otic region in all species bears lateral, dorsolateral, adlateral and median cristae, which raise the dermal skull-roof above the surface of the neurocranium to leave wide passages for divisions of the adductor mandibulae muscles. The lateral face of the otic region bears an extensive hyomandibular facet which straddles the jugular canal. An adjacent, unossified area may be the site of Pinkus' organ (the spiracular sense organ). More ventrally, on the edge of the quadrate, there is a prominent bulge for the hyosuspensory ligament; and on the ventral surface of the neurocranium there is an articulation area for the first gill-arch, which has previously been interpreted as the foramen for a hypothetical R. ventralis IX. The jugular groove is partly closed in by a prominent adotic process in Griphognathus and a small adotic eminence is present in the same position in other species. The cavum epiptericum, and the passages for all the major nerves and vessels in all the species can be interpreted by comparison with Recent dipnoans, particularly Neoceratodus. However, there is no clear passage for the efferent pseudobranchial artery in Griphognathus; the posterior cerebral vein of Holodipterus appears to have formed a network of vessels which passed out through several foramina in the otic region, rather than through the vagus foramen; and there is a network of canals draining into the orbit from the base of the cranium in Chirodipterus and Holodipterus, otherwise known only in Dipnorhynchus. There is an extensive supraotic cavity in the Gogo dipnoans, as in Eusthenopteron, with an anterior paired and a posterior median division. This cavity housed extensive endolymphatic sacs. The paired endolymphatic duct opened on the surface of the neurocranium and extended up to the dermal skull-roof in a groove on the dorsolateral crista. It may have opened to the outside in at least some specimens of Griphognathus. The nasal cavities are open ventrally and there is a broad internasal septum as in other Devonian dipnoans; the anterior nasal opening notches the upper lip. Griphognathus is unique in having the nasal cavity partly floored, and in having a well-defined posterior nasal opening between dermal bones of the palate. The dermal bones of the palate and ventral surface of the neurocranium include a parasphenoid with a long posterior stem and closed buccohypophysial canal, entopterygoid, dermopalatines and vomer. A posterior pit between the parasphenoid and neurocranium received the aortic ligament in Griphognathus. There are several dermopalatines in Griphognathus and Holodipterus, but only one in Chirodipterus. There is also an ectopterygoid in Griphognathus and possibly in Holodipterus. The vomer is a median element in Chirodipterus and Holodipterus; its presence in Griphognathus is unconfirmed. Thickenings on the dermal upper lip may indicate the inclusion of a premaxilla in the dermal snout. A vestigial maxilla may be present in Griphognathus in the form of tooth-plates lying in the lateral wall of the nasal cavity. The lower jaw ramus is elongated in Griphognathus and there is a short retroarticular process; but the number of dermal bones is reduced from the primitive dipnoan number of seven, and the infradentary series is represented by only two main elements. The adductor pit is closed, indicating that the muscles inserted on the lateral face ot the angular. Both Chirodipterus and Holodipterus retain the primitive number of dermal bones. The jaw of Chirodipterus is similar to that of Dipterus valenciennesi but it is relatively broader. That of Holodipterus is exceptionally powerful. Both of these Gogo forms have a wide-open adductor pit. Previous approaches to the interpretation of dermal bones of the skull-roof and cheek of Devonian dipnoans are reviewed critically to diminish the risk of reaching false phylogenetic conclusions. The lateral-lines and bone patterns of Griphognathus and Chirodipterus are normal for these sorts of dipnoans; those of Holodipterus are less well known but present no unusual features. The operculo-gular and submandibular series in all Gogo genera conform to the expected pattern: Chirodipterus australis may be exceptional in having only one subopercular bone. A fine dermal ornament is present in Griphognathus and Holodipterus, both of which lack cosmine on the head. Chirodipterus, however, is a cosmine-bearing dipnoan, and this tissue displays all the qualities previously recorded in dipterids, including complete resorption of the outer layers of the dermal snout in some specimens. In all genera, the lateral-lines open by small pores and there are richly developed rostral and symphysial tubuli. The hyoid and branchial arches are known in all species, but they are most completely preserved in Griphognathus. They answer closely to those of Neoceratodus. There is a hyomandibula, accessory element (in one specimen only), large ceratohyal and hypohyal. The gill-arches appear to lack pharyngobranchials; they clearly lack hypobranchials. The basi-branchial series comprises a large anterior and a small posterior element, the first of which is co-ossified with an elongated basihyal (“sublingual rod”) in Griphognathus. There is no sign of an ossified basihyal in the other forms. In Griphognathus alone, there is a urohyal which articulates with the basibranchial series, and paired anterior and posterior basibranchial tooth-plates. The principal conclusions about the interrelationships of dipnoans are that previous systems are grossly unparsimonious, but that it is not possible to replace them with a satisfactory phylogenetic scheme. The most primitive species is Dipnorhynchus sussmilchi. A series of derived characters can be recognized at more advanced levels, of which the most important involves the closure of the pineal foramen, changes in the dermal bone and lateral-line patterns of the skull-roof, modifications in the parasphenoid, and the origin and development of highly organized entopterygoid and prearticular tooth-plates. These changes permit a rudimentary cladogram to be constructed, but this is, perforce, reminiscent of an anagenetic analysis. Many dipnoans cannot be classified in a phylogenetic scheme, including Chirodipterus and Holodipterus. Other conclusions are that Griphognathus is a rhynchodipterid, and therefore most closely related to Rhynchodipterus and Soederberghia; dipterids, in the accepted sense (including Dipterus valenciennesi, Rhinodipterus and Chirodipterus), probably form a grade group of unspecialized, cosmine-bearing Devonian dipnoans; and that Neoceratodus and lepidosirenids are more closely related to each other than they are to Ceratodus and Triassic forms, or to gnathorhizids. The principal broader phylogenetic conclusions concern the interrelationships of sarcoptery-gians, i.e. dipnoans, actinistians and choanates. The teleostome status of dipnoans is corroborated by a number of new observations, including the cranial fissure, supraotic cavity, urohyal, basibranchial tooth-plates and aortic ligament. Sarcopterygians are assumed to be the collateral descendants (sister group) of actinopterygians, and Westoll's hypothesis that the intracranial joint is a primitive sarcopterygian character is upheld, against the author's previous opinion. Other sarcopterygian specializations are found in the general form of the otic and occipital region, the extensive hyomandibular facet(s) and the adotic process. The intracranial joint is secondarily absent in dipnoans, but these fishes are more closely related to choanates than they are to actinistians by several specializations, including the presence of cosmine, submandibular bones and a highly-differentiated supraotic cavity. The first two of these specializations are also found in onychodontids, which may therefore be choanates.",
    url = "https://doi.org/10.1111/j.1096-3642.1977.tb01031.x",
    doi = "10.1111/j.1096-3642.1977.tb01031.x",
    openalex = "W1995522526",
    references = "doi101001jama193602770270072040, doi1010079781468464658, doi101038142004a0, doi101146annureven10010165000525, doi1023071437499, doi1023071447582, doi1023071539358, doi1023072104331, doi1023072412482, doi1023072421869, doi105962bhltitle159141, doi105962bhltitle6408, doi105962bhltitle82144, openalexw1562680794, romer1942endocranial, thomson1969the"
}

@misc{strmer1978the3,
    author = "Strmer, W. and Bergstrm, J",
    title = "The arthropod Cheloniellon from the Devonian Hunsrck Shale",
    year = "1978",
    howpublished = "Palontologische Zeitschrift, v. 52, p. 57-81",
    note = "talkorigins\_source = {true}; raw\_reference = {Strmer, W., and Bergstrm, J., 1978, The arthropod Cheloniellon from the Devonian Hunsrck Shale: Palontologische Zeitschrift, v. 52, p. 57-81.}"
}

@misc{halstead1979agnathans1,
    author = "Halstead, L. B. and Liu, Y.-H. and P'an, K",
    title = "Agnathans from the Devonian of China",
    year = "1979",
    howpublished = "Nature, v. 282, p. 831-833",
    note = "talkorigins\_source = {true}; raw\_reference = {Halstead, L. B., Liu, Y.-H., and P'an, K., 1979, Agnathans from the Devonian of China: Nature, v. 282, p. 831-833.}"
}

This paper presents a structural interpretation of a part of the central and northern Appalachian foreland using the correlation in orientation of such deformation features as mechanical twins, solution cleavage, crenulation cleavage, pencils, joints, and deformed fossils. Such a correlation suggests that, within the central Appalachians, the Alleghanian orogeny consists of two major phases: a deformation possibly as old as Pennsylvanian, herein called the Lackawanna phase, and a second deformation, termed the Main phase of Permian or younger age. Effects of the Lackawanna phase deformation are found mainly in the Hudson River Valley and Pocono plateau, while effects in the...

@incollection{doi101130mem158p161,
    author = "Geiser, Peter and Engelder, Terry",
    title = "The distribution of layer parallel shortening fabrics in the Appalachian foreland of New York and ‘Pennsylvania: Evidence for two non-coaxial phases of the Alleghanian orogeny",
    year = "1983",
    booktitle = "Memoir - Geological Society of America",
    abstract = "This paper presents a structural interpretation of a part of the central and northern Appalachian foreland using the correlation in orientation of such deformation features as mechanical twins, solution cleavage, crenulation cleavage, pencils, joints, and deformed fossils. Such a correlation suggests that, within the central Appalachians, the Alleghanian orogeny consists of two major phases: a deformation possibly as old as Pennsylvanian, herein called the Lackawanna phase, and a second deformation, termed the Main phase of Permian or younger age. Effects of the Lackawanna phase deformation are found mainly in the Hudson River Valley and Pocono plateau, while effects in the...",
    url = "https://doi.org/10.1130/mem158-p161",
    doi = "10.1130/mem158-p161",
    openalex = "W2416948670"
}

(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.

@misc{doi105281zenodo16239053,
    author = "Gardiner, B. G.",
    title = "The relationships of the palaeoniscid fishes, a review based on new specimens of Mimia and Moythomasia from the Upper Devonian of Western Australia",
    year = "1984",
    booktitle = "Biodiversity Heritage Library (Smithsonian Institution)",
    abstract = "(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.",
    url = "https://doi.org/10.5281/zenodo.16239053",
    doi = "10.5281/zenodo.16239053",
    openalex = "W2621679539"
}

The Late Devonian Catskill Delta is made up of marine and non-marine facies built up on the flank of the tectonic Appalachian Peninsula during assembly of the Old Red (Laurasian) Continent. Much of the continent was under the influence of tropical climates showing a wide range of rainfall. Over the delta, the climate was either tropical wet and dry or desert, due in part, to a rainshadow effect caused by the mountains to the east. Streams showed great variations in discharge and an extended period of drought was an annual event over the region. Alluvial processes were dominant on land. Braided streams deposited the coarsest sediments on alluvial fans and sinuous, channelized streams deposited sand and mud on the alluvial plains. Interfluves on the alluvial plains were sufficiently long-lived to permit the formation of carbonate soils. Plants were most common near stream courses. Fine sand and mud were carried across the shoreline in distributaries to the floor of the adjacent Catskill Sea. Deltaic processes, wave-related processes, and tides shaped the shore. Wave-related processes and bioturbation modified and reworked the shallow marine sediments while turbidity currents and slow deposition from suspension were most effective over the rest of the basin.

@incollection{doi101130spe201p51,
    author = "Woodrow, Donald L.",
    title = "Paleogeography, paleoclimate, and sedimentary processes of the Late Devonian Catskill Delta",
    year = "1985",
    booktitle = "Geological Society of America eBooks",
    abstract = "The Late Devonian Catskill Delta is made up of marine and non-marine facies built up on the flank of the tectonic Appalachian Peninsula during assembly of the Old Red (Laurasian) Continent. Much of the continent was under the influence of tropical climates showing a wide range of rainfall. Over the delta, the climate was either tropical wet and dry or desert, due in part, to a rainshadow effect caused by the mountains to the east. Streams showed great variations in discharge and an extended period of drought was an annual event over the region. Alluvial processes were dominant on land. Braided streams deposited the coarsest sediments on alluvial fans and sinuous, channelized streams deposited sand and mud on the alluvial plains. Interfluves on the alluvial plains were sufficiently long-lived to permit the formation of carbonate soils. Plants were most common near stream courses. Fine sand and mud were carried across the shoreline in distributaries to the floor of the adjacent Catskill Sea. Deltaic processes, wave-related processes, and tides shaped the shore. Wave-related processes and bioturbation modified and reworked the shallow marine sediments while turbidity currents and slow deposition from suspension were most effective over the rest of the basin.",
    url = "https://doi.org/10.1130/spe201-p51",
    doi = "10.1130/spe201-p51",
    openalex = "W2463989544"
}

The Upper Devonian Catskill Formation was sampled for paleomagnetic study in east‐central Pennsylvania (41°N, 76°W). In one area the dominant component of magnetization (SE) is revealed over a broad spectrum of demagnetization temperatures ranging to at least 660°C. A conventional fold test is positive at the 99% confidence level. However, statistical analysis of dispersion with incremental bedding tilt correction shows a significant peak in the precision parameter after about 3/4 unfolding. The magnetization is therefore secondary, with a mean direction of D = 166.6°, I = −1.8°. The corresponding pole position (48.1°N, 124.1°E, a95 = 4.0°) is indistinguishable from paleopoles from earlier studies of the Catskill, which therefore can also be regarded as representing Permo‐Carboniferous remagnetizations. A second component of magnetization (SW, pole position 32.8°N, 90.0°E, a95 = 7.2°) with discrete unblocking temperature spectra and southwesterly declination was isolated in a few samples from the first area and in most samples from a second area. A prefolding origin of this magnetization is supported by a positive fold test on five samples from the first area. If this magnetization does represent a Devonian magnetization then the true paleolatitude for east‐central Pennsylvania is 16° +/− 7.2°S, which is consistent with the paleolatitude observed in many of the Upper Devonian rock units in the Acadia region, although inconsistent with others. The question of the position of Acadia relative to North America in the Upper Devonian is therefore still open.

@article{doi101029jb091ib12p12791,
    author = "Miller, John and Kent, Dennis V.",
    title = "Synfolding and prefolding magnetizations in the Upper Devonian Catskill Formation of eastern Pennsylvania: Implications for the tectonic history of Acadia",
    year = "1986",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "The Upper Devonian Catskill Formation was sampled for paleomagnetic study in east‐central Pennsylvania (41°N, 76°W). In one area the dominant component of magnetization (SE) is revealed over a broad spectrum of demagnetization temperatures ranging to at least 660°C. A conventional fold test is positive at the 99\% confidence level. However, statistical analysis of dispersion with incremental bedding tilt correction shows a significant peak in the precision parameter after about 3/4 unfolding. The magnetization is therefore secondary, with a mean direction of D = 166.6°, I = −1.8°. The corresponding pole position (48.1°N, 124.1°E, a95 = 4.0°) is indistinguishable from paleopoles from earlier studies of the Catskill, which therefore can also be regarded as representing Permo‐Carboniferous remagnetizations. A second component of magnetization (SW, pole position 32.8°N, 90.0°E, a95 = 7.2°) with discrete unblocking temperature spectra and southwesterly declination was isolated in a few samples from the first area and in most samples from a second area. A prefolding origin of this magnetization is supported by a positive fold test on five samples from the first area. If this magnetization does represent a Devonian magnetization then the true paleolatitude for east‐central Pennsylvania is 16° +/− 7.2°S, which is consistent with the paleolatitude observed in many of the Upper Devonian rock units in the Acadia region, although inconsistent with others. The question of the position of Acadia relative to North America in the Upper Devonian is therefore still open.",
    url = "https://doi.org/10.1029/jb091ib12p12791",
    doi = "10.1029/jb091ib12p12791",
    openalex = "W2150212227",
    references = "doi1010160012821x75902216, doi101098rspa19530064, doi101111j1365246x1956tb05560x, doi101111j1365246x1964tb06300x, doi101111j1365246x1980tb02601x, doi101111j1365246x1981tb02729x, doi10113000917613198311221dmcays20co2, doi101130mem158p161, openalexw2974218786, openalexw2989049194"
}

@book{doi104095120614,
    author = "Richardson, John B. and McGregor, D C",
    title = "Silurian and devonian spore zones of the Old Red Sandstone Continent and adjacent regions",
    year = "1986",
    url = "https://doi.org/10.4095/120614",
    doi = "10.4095/120614",
    openalex = "W2910189912"
}

@article{doi1011300091761319890170811fftudo23co2,
    author = "Long, John A. and Burrett, Clive",
    title = "Fish from the Upper Devonian of the Shan-Thai terrane indicate proximity to east Gondwana and south China terranes",
    year = "1989",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1989)017<0811:fftudo>2.3.co;2",
    doi = "10.1130/0091-7613(1989)017<0811:fftudo>2.3.co;2",
    openalex = "W2053838218",
    references = "doi101029tc007i003p00351"
}

Abstract Silurian and Early Devonian ostracode associations in North America represent at least three ecotypes, a leperditicopid association, a large beyrichiacean association, a mixed association, and possibly a fourth, spinose podocopid association, or Thuringian ecotype. Comparison of the large beyrichiacean association and mixed association ecotypes indicates the presence of three informal ostracode provinces, the Appohimchi, Baltic-British and Cordilleran, which remained relatively constant in geographical position throughout the Silurian and Early Devonian. Plotting the provinces on palaeogeographic maps suggests that temperature was not an important factor in delimiting the provinces, and land barriers, or possibly deep-water troughs as barriers, were the cause of provincial development. Benthic ostracodes differed from other benthic invertebrates such as brachiopods and corals in developing provincialism in the late Llandovery and having it start to decline in the Pragian through the Emsian.

@article{doi101144gslmem19900120121,
    author = "Berdan, Jean Milton",
    title = "The Silurian and Early Devonian biogeography of ostracodes in North America",
    year = "1990",
    journal = "Geological Society London Memoirs",
    abstract = "Abstract Silurian and Early Devonian ostracode associations in North America represent at least three ecotypes, a leperditicopid association, a large beyrichiacean association, a mixed association, and possibly a fourth, spinose podocopid association, or Thuringian ecotype. Comparison of the large beyrichiacean association and mixed association ecotypes indicates the presence of three informal ostracode provinces, the Appohimchi, Baltic-British and Cordilleran, which remained relatively constant in geographical position throughout the Silurian and Early Devonian. Plotting the provinces on palaeogeographic maps suggests that temperature was not an important factor in delimiting the provinces, and land barriers, or possibly deep-water troughs as barriers, were the cause of provincial development. Benthic ostracodes differed from other benthic invertebrates such as brachiopods and corals in developing provincialism in the late Llandovery and having it start to decline in the Pragian through the Emsian.",
    url = "https://doi.org/10.1144/gsl.mem.1990.012.01.21",
    doi = "10.1144/gsl.mem.1990.012.01.21",
    openalex = "W2015373911",
    references = "openalexw2726120922"
}

ABSTRACT The morphology and geochemistry of pedogenic carbonate found in vertic claystone palaeosols in the Devonian Catskill Formation in central Pennsylvania preserve a record of the physical and chemical environment of carbonate precipitation. The carbonate is characterized by three distinct petrographic generations. Pedogenic rhizoliths and nodules are the earliest precipitated generation, and typically consist of dull red‐brown luminescent micrite. Clear, equant calcite spar cement fills voids in the centres of rhizoliths, as well as circumgranular cracks and septarian voids in nodules. Early spar cements are non‐luminescent to dull luminescent, whereas later spar cements exhibit bright yellow‐orange luminescence. Late stage pedogenic fractures are always occluded with very bright yellow‐orange luminescent spar cements. The incorporation of progressively higher concentrations of Mn (up to 34000 ppm) into successively younger calcite spar cements, without concomitant increases in Fe, suggests carbonate precipitation from an evolving meteoric water in which Mn 2+ became increasingly mobile over time. The increased mobility is possibly due to decreasing Eh, resulting from oxidation of organic matter after rapid soil burial on the floodplain. The amount of Fe 2+ available for incorporation into calcite was limited because most iron was immobile, having been earlier oxidized and bound to the palaeosol clay matrix as a poorly crystallized ferric oxide or oxyhydroxide mineral. Carbon isotope compositions of pedogenic carbonate correlate with the inferred depth of carbonate precipitation. Rhizoliths preserved below the lowest stratigraphic occurrences of pedogenic slickensides are consistently depleted in 13 C relative to nodules, which formed stratigraphically higher, within the zone of active soil shrink and swell processes. Nodular carbonate, precipitated in proximity to deep cracks in the soil, is enriched due to increased gas exchange with isotopically heavy atmospheric CO 2. Accordingly, rhizolith compositions will most accurately estimate palaeoatmospheric levels of CO 2; the use of nodule compositions may result in overestimation of P CO 2 by as much as 30%.

@article{doi101111j136530911993tb01761x,
    author = "Driese, Steven G. and Mora, Claudia I.",
    title = "Physico‐chemical environment of pedogenic carbonate formation in Devonian vertic palaeosols, central Appalachians, USA",
    year = "1993",
    journal = "Sedimentology",
    abstract = "ABSTRACT The morphology and geochemistry of pedogenic carbonate found in vertic claystone palaeosols in the Devonian Catskill Formation in central Pennsylvania preserve a record of the physical and chemical environment of carbonate precipitation. The carbonate is characterized by three distinct petrographic generations. Pedogenic rhizoliths and nodules are the earliest precipitated generation, and typically consist of dull red‐brown luminescent micrite. Clear, equant calcite spar cement fills voids in the centres of rhizoliths, as well as circumgranular cracks and septarian voids in nodules. Early spar cements are non‐luminescent to dull luminescent, whereas later spar cements exhibit bright yellow‐orange luminescence. Late stage pedogenic fractures are always occluded with very bright yellow‐orange luminescent spar cements. The incorporation of progressively higher concentrations of Mn (up to 34000 ppm) into successively younger calcite spar cements, without concomitant increases in Fe, suggests carbonate precipitation from an evolving meteoric water in which Mn 2+ became increasingly mobile over time. The increased mobility is possibly due to decreasing Eh, resulting from oxidation of organic matter after rapid soil burial on the floodplain. The amount of Fe 2+ available for incorporation into calcite was limited because most iron was immobile, having been earlier oxidized and bound to the palaeosol clay matrix as a poorly crystallized ferric oxide or oxyhydroxide mineral. Carbon isotope compositions of pedogenic carbonate correlate with the inferred depth of carbonate precipitation. Rhizoliths preserved below the lowest stratigraphic occurrences of pedogenic slickensides are consistently depleted in 13 C relative to nodules, which formed stratigraphically higher, within the zone of active soil shrink and swell processes. Nodular carbonate, precipitated in proximity to deep cracks in the soil, is enriched due to increased gas exchange with isotopically heavy atmospheric CO 2. Accordingly, rhizolith compositions will most accurately estimate palaeoatmospheric levels of CO 2; the use of nodule compositions may result in overestimation of P CO 2 by as much as 30\%.",
    url = "https://doi.org/10.1111/j.1365-3091.1993.tb01761.x",
    doi = "10.1111/j.1365-3091.1993.tb01761.x",
    openalex = "W2137028658",
    references = "banks1985the, doi1010029780470698716, doi1010160012821x8490089x, doi101016b9780444408266500078, doi101038205587a0, doi10106311747785, doi101111j136530911980tb01651x, doi101130spe203p1, doi10130674d714f62b2111d78648000102c1865d, openalexw1488282249"
}

Abstract Ventastega curonica, from the Upper Famennian Ketleri Formation, is the first tetrapod find from the Upper Devonian of Latvia, and only the fourth adequately represented Devonian tetrapod genus to be described. The taxon is represented by disarticulated cranial and postcranial elements from two localities, Ketleri on the Venta River and Pavari on the Ciecere River. A second tetrapod, represented by a single mandibular fragment, appears to be present at Ketleri. The lower jaw of Ventastega is strikingly primitive in retaining fangs on the coronoid series, but shares many characters with those of other known Devonian tetrapods. Some of these features are interpreted as basal tetrapod synapomorphies; they provide a new data set for the identification of isolated tetrapod jaw fragments, and confirm the (previously disputed) tetrapod status of Metaxygnathus. The upper jaw bones of Ventastega are broadly similar to those of Acanthostega, Ichthyostega and Tulerpeton, as is the narial region. The lateral rostral bone is either very small or absent. A preopercular bone is present in the cheek, and the lacrimal is excluded from the orbit. The palate is closed. Palatine and vomer bear fangs which are set in the marginal tooth row. An isolated iliac blade from Pavari, probably attributable to Ventastega, resembles that of Acanthostega but may not have carried a dorsal process. Two clavicles from Pavari and Ketleri which may also belong to Ventastega are of a typical early tetrapod pattern, similar to Greerpeton but with a broader ventral blade. Non-attributable or doubtfully attributable bones from Ketleri include a probable tetrapod postorbital and a possible limb bone. Ventastega appears to be a tetrapod of the same broad `grade' as Ichthyostega and Acanthostega, but is arguably more primitive than either.

@article{doi101098rstb19940027,
    author = "Ahlberg, Per and Lukševičs, Ervīns and Lebedev, Oleg A.",
    title = "The First Tetrapod Finds from the Devonian (Upper Famennian) of Latvia",
    year = "1994",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "Abstract Ventastega curonica, from the Upper Famennian Ketleri Formation, is the first tetrapod find from the Upper Devonian of Latvia, and only the fourth adequately represented Devonian tetrapod genus to be described. The taxon is represented by disarticulated cranial and postcranial elements from two localities, Ketleri on the Venta River and Pavari on the Ciecere River. A second tetrapod, represented by a single mandibular fragment, appears to be present at Ketleri. The lower jaw of Ventastega is strikingly primitive in retaining fangs on the coronoid series, but shares many characters with those of other known Devonian tetrapods. Some of these features are interpreted as basal tetrapod synapomorphies; they provide a new data set for the identification of isolated tetrapod jaw fragments, and confirm the (previously disputed) tetrapod status of Metaxygnathus. The upper jaw bones of Ventastega are broadly similar to those of Acanthostega, Ichthyostega and Tulerpeton, as is the narial region. The lateral rostral bone is either very small or absent. A preopercular bone is present in the cheek, and the lacrimal is excluded from the orbit. The palate is closed. Palatine and vomer bear fangs which are set in the marginal tooth row. An isolated iliac blade from Pavari, probably attributable to Ventastega, resembles that of Acanthostega but may not have carried a dorsal process. Two clavicles from Pavari and Ketleri which may also belong to Ventastega are of a typical early tetrapod pattern, similar to Greerpeton but with a broader ventral blade. Non-attributable or doubtfully attributable bones from Ketleri include a probable tetrapod postorbital and a possible limb bone. Ventastega appears to be a tetrapod of the same broad `grade' as Ichthyostega and Acanthostega, but is arguably more primitive than either.",
    url = "https://doi.org/10.1098/rstb.1994.0027",
    doi = "10.1098/rstb.1994.0027",
    openalex = "W2108665316"
}

We have carried out a palaeomagnetic investigation of the upper middle Devonian marly limestone of the Hazzel Matti Formation outcropping at Meredoua in the northern Ahaggar in the Sahara Desert. The Givetian age of the formation is well constrained by palaeontological arguments. The formation has been deformed later than the Moscovian (upper middle Carboniferous). In the altered yellowish samples and in the heterogeneous samples made of mixed fresh and altered zones, several obviously secondary magnetization components are present. In the freshest bluegrey samples a SE down-dipping component can be isolated, particularly when a combined thermal and AF treatment is applied. This component, observed in 53 samples from three sites, passes the fold test of McFadden & Lowes (1981) and McFadden & Jones (1981) at the 95 per cent probability level. the mean direction for the three sites after tilt correction is: D s = 118.9°, I s,=34.2°, k = 378, α 95 = 6.3°, which corresponds to a south pole (MER) situated at φ p = 61.7°, λ p = -16.2°, A 95 = 4.2° and places the site area under a palaeolatitude of -18.8°. However, the best grouping of the directions is achieved after 85 per cent of unfolding using a statistical method based on a bivariate extension of the Fisher's statistics (Legoff 1990; Legoff, Henry & Daly 1992). Such a tilt correction changes the pole position by 1.5°. As the α 95 and K curves obtained from stepwise unfolding display a broad minimum and maximum value respectively, and because there was probably slight original syn-sedimentary dips, it is likely that 85 per cent of tilt correction is not significantly different from complete unfolding. The magnetic behaviour of the samples upon thermal and AF demagnetization, the evolution of the initial susceptibility upon thermal treatment, hysteresis cycles and investigation of the magnetic mineralogy through microscope examination and electron microprobe analyses lead to the following conclusion: greigite was probably a primary magnetic mineral formed during the diagenesis of the rock. However, its primary magnetization has been totally replaced by a VRM, except perhaps in rare samples in which the SE component can be found in the narrow range of 300–350°C. Magnetite is thought to carry the SE magnetization component and may have formed early during the diagenesis or soon after greigite. To consider the fold test negative would assign the MER pole a post-Moscovian age and place it in a situation inconsistent with the other poles of the West Gondwanian APWP, unless all the middle Carboniferous and probably lower Permian African poles are rejuvenated. We rather favour the interpretation of a positive fold test, which however does not constrain the magnetization to be of primary Givetian age; the SE component may as well have been acquired any time between the Givetian and at least the late Moscovian. Assuming that the MER pole has a Givetian age implies that the Rheic Ocean, which separated Laurussia from Gondwana in the early Palaeozoic, was almost closed in the middle Devonian, in agreement with palaeobiogeographic arguments; but it increases the discrepancy between the APWP of respectively West and East Gondwana. An intermediate lower Carboniferous age might be in better agreement with both African and Australian data. Clearly, however, more Gondwanian poles are needed to test the reliability of both West and East Gondwanian APWP, and check simultaneously the possibility of relative displacements between these two blocks during the Devono-Carboniferous time period.

@article{doi101111j1365246x1994tb00920x,
    author = "Smith, Brigitte and Moussine‐Pouchkine, Alexis and Ahmed, Ali Aït Kaci",
    title = "Palaeomagnetic investigation of Middle Devonian limestones of Algeria and the Gondwana reconstruction",
    year = "1994",
    journal = "Geophysical Journal International",
    abstract = "We have carried out a palaeomagnetic investigation of the upper middle Devonian marly limestone of the Hazzel Matti Formation outcropping at Meredoua in the northern Ahaggar in the Sahara Desert. The Givetian age of the formation is well constrained by palaeontological arguments. The formation has been deformed later than the Moscovian (upper middle Carboniferous). In the altered yellowish samples and in the heterogeneous samples made of mixed fresh and altered zones, several obviously secondary magnetization components are present. In the freshest bluegrey samples a SE down-dipping component can be isolated, particularly when a combined thermal and AF treatment is applied. This component, observed in 53 samples from three sites, passes the fold test of McFadden \& Lowes (1981) and McFadden \& Jones (1981) at the 95 per cent probability level. the mean direction for the three sites after tilt correction is: D s = 118.9°, I s,=34.2°, k = 378, α 95 = 6.3°, which corresponds to a south pole (MER) situated at φ p = 61.7°, λ p = -16.2°, A 95 = 4.2° and places the site area under a palaeolatitude of -18.8°. However, the best grouping of the directions is achieved after 85 per cent of unfolding using a statistical method based on a bivariate extension of the Fisher's statistics (Legoff 1990; Legoff, Henry \& Daly 1992). Such a tilt correction changes the pole position by 1.5°. As the α 95 and K curves obtained from stepwise unfolding display a broad minimum and maximum value respectively, and because there was probably slight original syn-sedimentary dips, it is likely that 85 per cent of tilt correction is not significantly different from complete unfolding. The magnetic behaviour of the samples upon thermal and AF demagnetization, the evolution of the initial susceptibility upon thermal treatment, hysteresis cycles and investigation of the magnetic mineralogy through microscope examination and electron microprobe analyses lead to the following conclusion: greigite was probably a primary magnetic mineral formed during the diagenesis of the rock. However, its primary magnetization has been totally replaced by a VRM, except perhaps in rare samples in which the SE component can be found in the narrow range of 300–350°C. Magnetite is thought to carry the SE magnetization component and may have formed early during the diagenesis or soon after greigite. To consider the fold test negative would assign the MER pole a post-Moscovian age and place it in a situation inconsistent with the other poles of the West Gondwanian APWP, unless all the middle Carboniferous and probably lower Permian African poles are rejuvenated. We rather favour the interpretation of a positive fold test, which however does not constrain the magnetization to be of primary Givetian age; the SE component may as well have been acquired any time between the Givetian and at least the late Moscovian. Assuming that the MER pole has a Givetian age implies that the Rheic Ocean, which separated Laurussia from Gondwana in the early Palaeozoic, was almost closed in the middle Devonian, in agreement with palaeobiogeographic arguments; but it increases the discrepancy between the APWP of respectively West and East Gondwana. An intermediate lower Carboniferous age might be in better agreement with both African and Australian data. Clearly, however, more Gondwanian poles are needed to test the reliability of both West and East Gondwanian APWP, and check simultaneously the possibility of relative displacements between these two blocks during the Devono-Carboniferous time period.",
    url = "https://doi.org/10.1111/j.1365-246x.1994.tb00920.x",
    doi = "10.1111/j.1365-246x.1994.tb00920.x",
    openalex = "W2171859076",
    references = "doi101029tc007i003p00351"
}

An early tetrapod fossil from the Upper Devonian of Pennsylvania (Catskill Formation) extends the temporal range of tetrapods in North America and suggests that they attained a virtually global equatorial distribution by the end of the Devonian. Derived features of the shoulder girdle indicate that appendicular mechanisms of support and propulsion were well developed even in the earliest phases of tetrapod history. The specialized morphology of the pectoral skeleton implies that the diversity of early tetrapods was great and is suggestive of innovative locomotor patterns in the first tetrapods.

@article{doi101126science2655172639,
    author = "Daeschler, Edward B. and Shubin, Neil H. and Thomson, Keith Stewart and Amaral, William W.",
    title = "A Devonian Tetrapod from North America",
    year = "1994",
    journal = "Science",
    abstract = "An early tetrapod fossil from the Upper Devonian of Pennsylvania (Catskill Formation) extends the temporal range of tetrapods in North America and suggests that they attained a virtually global equatorial distribution by the end of the Devonian. Derived features of the shoulder girdle indicate that appendicular mechanisms of support and propulsion were well developed even in the earliest phases of tetrapod history. The specialized morphology of the pectoral skeleton implies that the diversity of early tetrapods was great and is suggestive of innovative locomotor patterns in the first tetrapods.",
    url = "https://doi.org/10.1126/science.265.5172.639",
    doi = "10.1126/science.265.5172.639",
    openalex = "W2031549690"
}

@article{doi101016004019519400176a,
    author = "Hirt, Ann M. and Evans, Keith F. and Engelder, Terry",
    title = "Correlation between magnetic anisotropy and fabric for Devonian shales on the Appalachian Plateau",
    year = "1995",
    journal = "Tectonophysics",
    url = "https://doi.org/10.1016/0040-1951(94)00176-a",
    doi = "10.1016/0040-1951(94)00176-a",
    openalex = "W2160105114",
    references = "doi1010160040195185900332, doi101029gl012i006p00333, doi101029gl017i002p00159, doi101029jb091ib12p12791, doi101029jb095ib03p02753, doi101086628785, doi10113000167606196475863ttitpa20co2, doi10113000167606196778609jitapo20co2, doi10113000917613198311221dmcays20co2, doi101130spe201p39, doi101306m61588"
}

Postcranial remains of the Russian Late Devonian tetrapod Tulerpeton include the hexadactylous fore limb, hind limb, anocleithral pectoral girdle, squamation, and associated disarticulated postcranial bones. A cladistic analysis indicates that Tulerpeton is a reptiliomorph stem-group amniote and the earliest known crown-group tetrapod: Acanthostega and Ichthyostega are successively more derived plesion stem-group tetrapods and do not consititute a monophyletic ichthyostegalian radiation. Previous analyses suggesting a profound split in tetrapod phylogeny are thereby corroborated, and likewise the interpretation of Westlothiana as a stem-group amniote. The divergence of reptiliomorphs from batrachomorphs occurred before the Devonian-Carboniferous boundary. Tulerpeton originates from an entirely aquatic environment with a diverse fish fauna. The morphologies of its limbs and those of Devonian stem-tetrapods suggest that dactyly predates the elaboration of the carpus and tarsus, and that Polydactyly persisted after the evolutionary divergence of the principal lineages of living tetrapods. The apparent absence of a branchial lamina and gill skeleton suggests that Tulerpeton was primarily air-breathing, whereas contemporary stem-group tetrapods and more recent batrachomorphs retained greater emphasis on gill-breathing.

@article{doi101111j109636421995tb00119x,
    author = "Lebedev, Oleg A. and Coates, Michael I.",
    title = "The postcranial skeleton of the Devonian tetrapod Tulerpeton curtum Lebedev",
    year = "1995",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Postcranial remains of the Russian Late Devonian tetrapod Tulerpeton include the hexadactylous fore limb, hind limb, anocleithral pectoral girdle, squamation, and associated disarticulated postcranial bones. A cladistic analysis indicates that Tulerpeton is a reptiliomorph stem-group amniote and the earliest known crown-group tetrapod: Acanthostega and Ichthyostega are successively more derived plesion stem-group tetrapods and do not consititute a monophyletic ichthyostegalian radiation. Previous analyses suggesting a profound split in tetrapod phylogeny are thereby corroborated, and likewise the interpretation of Westlothiana as a stem-group amniote. The divergence of reptiliomorphs from batrachomorphs occurred before the Devonian-Carboniferous boundary. Tulerpeton originates from an entirely aquatic environment with a diverse fish fauna. The morphologies of its limbs and those of Devonian stem-tetrapods suggest that dactyly predates the elaboration of the carpus and tarsus, and that Polydactyly persisted after the evolutionary divergence of the principal lineages of living tetrapods. The apparent absence of a branchial lamina and gill skeleton suggests that Tulerpeton was primarily air-breathing, whereas contemporary stem-group tetrapods and more recent batrachomorphs retained greater emphasis on gill-breathing.",
    url = "https://doi.org/10.1111/j.1096-3642.1995.tb00119.x",
    doi = "10.1111/j.1096-3642.1995.tb00119.x",
    openalex = "W2039592421",
    references = "doi10100797814615698316, doi101016s0016699588800664, doi101038347066a0, doi101098rstb19840103, doi101111j109636421985tb01517x, doi101111j109636421991tb00905x, doi101130spe28p1, doi101146annureves23110192002313, doi1023072412685, doi1023072413058, doi1023073514548, doi105860choice300927, doi105962bhltitle82144"
}

ABSTRACT The postcranial skeleton of Acanthostega gunnari from the Famennian of East Greenland displays a unique, transitional, mixture of features conventionally associated with fishand tetrapod-like morphologies. The rhachitomous vertebral column has a primitive, barely differentiated atlas-axis complex, encloses an unconstricted notochordal canal, and the weakly ossified neural arches have poorly developed zygapophyses. More derived axial skeletal features include caudal vertebral proliferation and, transiently, neural radials supporting unbranched and unsegmented lepidotrichia. Sacral and post-sacral ribs reiterate uncinate cervical and anterior thoracic rib morphologies: a simple distal flange supplies a broad surface for iliac attachment. The octodactylous forelimb and hindlimb each articulate with an unsutured, foraminate endoskeletal girdle. A broad-bladed femoral shaft with extreme anterior torsion and associated flattened epipodials indicates a paddle-like hindlimb function. Phylogenetic analysis places Acanthostega as the sister-group of Ichthyostega plus all more advanced tetrapods. Tulerpeton appears to be a basal stemamniote plesion, tying the amphibian-amniote split to the uppermost Devonian. Caerorhachis may represent a more derived stem-amniote plesion. Postcranial evolutionary trends spanning the taxa traditionally associated with the fish-tetrapod transition are discussed in detail. Comparison between axial skeletons of primitive tetrapods suggests that plesiomorphic fish-like morphologies were re-patterned in a cranio-caudal direction with the emergence of tetrapod vertebral regionalisation. The evolution of digited limbs lags behind the initial enlargement of endoskeletal girdles, whereas digit evolution precedes the elaboration of complex carpal and tarsal articulations. Pentadactylous limbs appear to have stabilised independently in amniote and amphibian lineages; the colosteid Greererpeton has a pentadactylous manus, indicating that basal amphibian forelimbs may not be restricted to patterns of four digits or less.

@article{doi101017s0263593300006787,
    author = "Coates, Michael I.",
    title = "The Devonian tetrapod Acanthostega gunnari Jarvik: postcranial anatomy, basal tetrapod interrelationships and patterns of skeletal evolution",
    year = "1996",
    journal = "Transactions of the Royal Society of Edinburgh Earth Sciences",
    abstract = "ABSTRACT The postcranial skeleton of Acanthostega gunnari from the Famennian of East Greenland displays a unique, transitional, mixture of features conventionally associated with fishand tetrapod-like morphologies. The rhachitomous vertebral column has a primitive, barely differentiated atlas-axis complex, encloses an unconstricted notochordal canal, and the weakly ossified neural arches have poorly developed zygapophyses. More derived axial skeletal features include caudal vertebral proliferation and, transiently, neural radials supporting unbranched and unsegmented lepidotrichia. Sacral and post-sacral ribs reiterate uncinate cervical and anterior thoracic rib morphologies: a simple distal flange supplies a broad surface for iliac attachment. The octodactylous forelimb and hindlimb each articulate with an unsutured, foraminate endoskeletal girdle. A broad-bladed femoral shaft with extreme anterior torsion and associated flattened epipodials indicates a paddle-like hindlimb function. Phylogenetic analysis places Acanthostega as the sister-group of Ichthyostega plus all more advanced tetrapods. Tulerpeton appears to be a basal stemamniote plesion, tying the amphibian-amniote split to the uppermost Devonian. Caerorhachis may represent a more derived stem-amniote plesion. Postcranial evolutionary trends spanning the taxa traditionally associated with the fish-tetrapod transition are discussed in detail. Comparison between axial skeletons of primitive tetrapods suggests that plesiomorphic fish-like morphologies were re-patterned in a cranio-caudal direction with the emergence of tetrapod vertebral regionalisation. The evolution of digited limbs lags behind the initial enlargement of endoskeletal girdles, whereas digit evolution precedes the elaboration of complex carpal and tarsal articulations. Pentadactylous limbs appear to have stabilised independently in amniote and amphibian lineages; the colosteid Greererpeton has a pentadactylous manus, indicating that basal amphibian forelimbs may not be restricted to patterns of four digits or less.",
    url = "https://doi.org/10.1017/s0263593300006787",
    doi = "10.1017/s0263593300006787",
    openalex = "W2093430057",
    references = "doi10100797814615698316, doi101016s0016699588800664, doi101017cbo9780511565557, doi101017s0022336000021454, doi101038347066a0, doi101038362623a0, doi101098rstb19840103, doi101111j109600311988tb00514x, doi101111j109636421982tb01955x, doi101111j109636421985tb01517x, doi101111j109636421995tb00119x, doi101111j109636421995tb00932x, doi101111j150239311996tb01839x, doi101111j155856461981tb04969x, doi101130spe28p1, doi101242dev1212333, doi10182618200376605199601, doi1023071292217, doi1023072412182, doi1023072413058, doi1023073514548, doi105860choice300927, doi105962bhltitle82144, openalexw1567612426, openalexw1964182146"
}

@article{doi101111j150239311996tb01839x,
    author = "Jarvik, Erik",
    title = "The Devonian tetrapod Ichthyostega",
    year = "1996",
    journal = "Lethaia",
    url = "https://doi.org/10.1111/j.1502-3931.1996.tb01839.x",
    doi = "10.1111/j.1502-3931.1996.tb01839.x",
    openalex = "W2071577803"
}

The material of Ichthyostega Säve-Söderbergh 1932 collected by the Danish expeditions to East Greenland (1929-1955) led by Lauge Koch is described and documented by photographs of all important specimens. The ichthyostegids are related to the osteolepiforms, and comparisons with the Devonian osteolepiform fish Eusthenopteron and post-Devonian stegocephalians are made. In some respects the ichthyostegids are fish-like, whereas in others they have reached the tetrapod level. However, they also show specializations unparalleled in later tetrapods and belong to a sidebranch of the Osteolepipoda. Several new structures, such as canals for the occipital arteries, the prominent sacculus vesicle, the parotic crest of the palatoqudrate, the attachment areas for a paired basicranial muscle, and an arcual plate dorsal to the notochord are described. Special problems, e.g., the terminology of the dermal bones of the skull roof, cranial kinetism, resegmentation, the metapterygial stem, and the origin of the tetrapod limbs, are discussed. It is concluded that the hindlimb in Ichthyostega is pentadactyl and that pentadactyly is primitive for the Osteolepipoda.

@incollection{doi10182618200376605199601,
    author = "Jarvik, Erik",
    title = "The Devonian tetrapod Ichthyostega",
    year = "1996",
    booktitle = "Fossils and strata",
    abstract = "The material of Ichthyostega Säve-Söderbergh 1932 collected by the Danish expeditions to East Greenland (1929-1955) led by Lauge Koch is described and documented by photographs of all important specimens. The ichthyostegids are related to the osteolepiforms, and comparisons with the Devonian osteolepiform fish Eusthenopteron and post-Devonian stegocephalians are made. In some respects the ichthyostegids are fish-like, whereas in others they have reached the tetrapod level. However, they also show specializations unparalleled in later tetrapods and belong to a sidebranch of the Osteolepipoda. Several new structures, such as canals for the occipital arteries, the prominent sacculus vesicle, the parotic crest of the palatoqudrate, the attachment areas for a paired basicranial muscle, and an arcual plate dorsal to the notochord are described. Special problems, e.g., the terminology of the dermal bones of the skull roof, cranial kinetism, resegmentation, the metapterygial stem, and the origin of the tetrapod limbs, are discussed. It is concluded that the hindlimb in Ichthyostega is pentadactyl and that pentadactyly is primitive for the Osteolepipoda.",
    url = "https://doi.org/10.18261/8200376605-1996-01",
    doi = "10.18261/8200376605-1996-01",
    openalex = "W4385616984",
    references = "doi10100797814615698316, doi101016s0016699588800664, doi101038142004a0, doi101038347066a0, doi101242dev1994supplement169, doi1023071441916, doi1023072413058, doi1023072421869, doi105962bhltitle82144, openalexw1564473436"
}

@article{doi1023073515409,
    author = "Driese, Steven G. and Mora, Claudia I. and Elick, Jennifer M.",
    title = "Morphology and Taphonomy of Root and Stump Casts of the Earliest Trees (Middle to Late Devonian), Pennsylvania and New York, U.S.A.",
    year = "1997",
    journal = "Palaios",
    url = "https://doi.org/10.2307/3515409",
    doi = "10.2307/3515409",
    openalex = "W2330641881",
    references = "doi101007978364265923210, doi101038326869a0, doi101086628416, doi101098rstb19850074, doi101111j136530911980tb01651x, doi101111j136530911993tb01761x, doi1011300016760619931050129cop23co2, doi1011300091761319910191017cditpa23co2, doi101130spe201p39, doi101130spe201p51, doi101130spe216p1"
}

Abstract The lower jaw of the Devonian tetrapod Acanthostega is described for the first time. Redescriptions are provided for the lower jaws of the elpistostegid Panderichthys, the Devonian tetrapods Elginerpeton, Obruchevichthys, Metaxygnathus, Ventastega and Ichthyostega, and the Carboniferous tetrapods Crassigyrinus, Megalocephalus and Gephyrostegus. The character distri- butions thus revealed differ considerably from previous accounts, particularly in the wide distribution of certain primitive characters. Meckelian ossification in the middle part of the jaw is widespread among Devonian tetrapods, being demonstrably absent only in Acanthostega. Among Carboniferous tetrapods, a tooth-bearing parasymphysial plate is shown to be present in Crassigyrinus and Megalocephalus (having already been demonstrated by other authors in Whatcheeria and Greererpeton). A phylogenetic analysis of 26 early tetrapods including all the aforementioned genera, scored for 51 lower jaw characters, produces at least 2,500 equally parsimonious trees. However, the lack of resolution lies largely in a big top end polychotomy containing anthracosaurs, temnospondyls, seymouriamorphs, microsaurs and a nectridean-amniote clade. Below this polycho- tomy, which may correspond approximately to the tetrapod crown group, there is a well-resolved stem-group containing, in descending order, Megalocephalus, Greererpeton, Crassigyrinus, (jaws associated with) Tulerpeton, Whatcheeria, Acanthostega, Metaxygnathus, Ichthyostega, Ventastega and Metaxygnathus (unresolved), an Elginerpeton-Obruchevichthys clade, and Panderichthys. This conflicts with recently published phylogenies by Coates and Lebedev & Coates, which place Tulerpeton and all post-Devonian tetrapods in the amphibian or amniote branches of the tetrapod crown group.

@article{doi101017s0263593300002340,
    author = "Ahlberg, Per and Clack, Jennifer A.",
    title = "Lower jaws, lower tetrapods–a review based on the Devonian genus Acanthostega",
    year = "1998",
    journal = "Transactions of the Royal Society of Edinburgh Earth Sciences",
    abstract = "Abstract The lower jaw of the Devonian tetrapod Acanthostega is described for the first time. Redescriptions are provided for the lower jaws of the elpistostegid Panderichthys, the Devonian tetrapods Elginerpeton, Obruchevichthys, Metaxygnathus, Ventastega and Ichthyostega, and the Carboniferous tetrapods Crassigyrinus, Megalocephalus and Gephyrostegus. The character distri- butions thus revealed differ considerably from previous accounts, particularly in the wide distribution of certain primitive characters. Meckelian ossification in the middle part of the jaw is widespread among Devonian tetrapods, being demonstrably absent only in Acanthostega. Among Carboniferous tetrapods, a tooth-bearing parasymphysial plate is shown to be present in Crassigyrinus and Megalocephalus (having already been demonstrated by other authors in Whatcheeria and Greererpeton). A phylogenetic analysis of 26 early tetrapods including all the aforementioned genera, scored for 51 lower jaw characters, produces at least 2,500 equally parsimonious trees. However, the lack of resolution lies largely in a big top end polychotomy containing anthracosaurs, temnospondyls, seymouriamorphs, microsaurs and a nectridean-amniote clade. Below this polycho- tomy, which may correspond approximately to the tetrapod crown group, there is a well-resolved stem-group containing, in descending order, Megalocephalus, Greererpeton, Crassigyrinus, (jaws associated with) Tulerpeton, Whatcheeria, Acanthostega, Metaxygnathus, Ichthyostega, Ventastega and Metaxygnathus (unresolved), an Elginerpeton-Obruchevichthys clade, and Panderichthys. This conflicts with recently published phylogenies by Coates and Lebedev \& Coates, which place Tulerpeton and all post-Devonian tetrapods in the amphibian or amniote branches of the tetrapod crown group.",
    url = "https://doi.org/10.1017/s0263593300002340",
    doi = "10.1017/s0263593300002340",
    openalex = "W2154717138",
    references = "doi1010160169534789901626, doi101130spe28p1, doi101242dev122103229, doi1023071447582, doi1023072413058, doi1023072413376, doi1023072992353, doi1023072992407, doi105860choice300927, doi105962bhltitle82144"
}

The Devonian Period was characterized by major changes in both the terrestrial biosphere, e.g. the evolution of trees and seed plants and the appearance of multi–storied forests, and in the marine biosphere, e.g. an extended biotic crisis that decimated tropical marine benthos, especially the stromatoporoid–tabulate coral reef community. Teleconnections between these terrestrial and marine events are poorly understood, but a key may lie in the role of soils as a geochemical interface between the lithosphere and atmosphere/hydrosphere, and the role of land plants in mediating weathering processes at this interface. The effectiveness of terrestrial floras in weathering was significantly enhanced as a consequence of increases in the size and geographic extent of vascular land plants during the Devonian. In this regard, the most important palaeobotanical innovations were (1) arborescence (tree stature), which increased maximum depths of root penetration and rhizoturbation, and (2) the seed habit, which freed land plants from reproductive dependence on moist lowland habitats and allowed colonization of drier upland and primary successional areas. These developments resulted in a transient intensification of pedogenesis (soil formation) and to large increases in the thickness and areal extent of soils. Enhanced chemical weathering may have led to increased riverine nutrient fluxes that promoted development of eutrophic conditions in epicontinental seaways, resulting in algal blooms, widespread bottomwater anoxia, and high sedimentary organic carbon fluxes. Long–term effects included drawdown of atmospheric pCO 2 and global cooling, leading to a brief Late Devonian glaciation, which set the stage for icehouse conditions during the Permo–Carboniferous. This model provides a framework for understanding links between early land plant evolution and coeval marine anoxic and biotic events, but further testing of Devonian terrestrial–marine teleconnections is needed.

@article{doi101098rstb19980195,
    author = "Algeo, Thomas J. and Scheckler, Stephen E.",
    title = "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events",
    year = "1998",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "The Devonian Period was characterized by major changes in both the terrestrial biosphere, e.g. the evolution of trees and seed plants and the appearance of multi–storied forests, and in the marine biosphere, e.g. an extended biotic crisis that decimated tropical marine benthos, especially the stromatoporoid–tabulate coral reef community. Teleconnections between these terrestrial and marine events are poorly understood, but a key may lie in the role of soils as a geochemical interface between the lithosphere and atmosphere/hydrosphere, and the role of land plants in mediating weathering processes at this interface. The effectiveness of terrestrial floras in weathering was significantly enhanced as a consequence of increases in the size and geographic extent of vascular land plants during the Devonian. In this regard, the most important palaeobotanical innovations were (1) arborescence (tree stature), which increased maximum depths of root penetration and rhizoturbation, and (2) the seed habit, which freed land plants from reproductive dependence on moist lowland habitats and allowed colonization of drier upland and primary successional areas. These developments resulted in a transient intensification of pedogenesis (soil formation) and to large increases in the thickness and areal extent of soils. Enhanced chemical weathering may have led to increased riverine nutrient fluxes that promoted development of eutrophic conditions in epicontinental seaways, resulting in algal blooms, widespread bottomwater anoxia, and high sedimentary organic carbon fluxes. Long–term effects included drawdown of atmospheric pCO 2 and global cooling, leading to a brief Late Devonian glaciation, which set the stage for icehouse conditions during the Permo–Carboniferous. This model provides a framework for understanding links between early land plant evolution and coeval marine anoxic and biotic events, but further testing of Devonian terrestrial–marine teleconnections is needed.",
    url = "https://doi.org/10.1098/rstb.1998.0195",
    doi = "10.1098/rstb.1998.0195",
    openalex = "W2019839279",
    references = "doi1010029780470698716, doi101007978364270831215, doi101007978364270831222, doi101007bf00926826, doi1010160016703783901515, doi1010160031018284900415, doi101038368619a0, doi10108011035898209455245, doi101086629850, doi101111j136530911993tb01761x, doi101126science21545391498, doi10113000167606198596567defie20co2, doi101130001676061986971262baiooi20co2, doi1015159780691220239, doi1023073243920, doi102475ajs294156, openalexw2989049194"
}

@article{doi101016s0031018298002181,
    author = "Caplan, Mark L. and Bustin, R.Mark",
    title = "Devonian–Carboniferous Hangenberg mass extinction event, widespread organic-rich mudrock and anoxia: causes and consequences",
    year = "1999",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/s0031-0182(98)00218-1",
    doi = "10.1016/s0031-0182(98)00218-1",
    openalex = "W2064725572",
    references = "doi1010160031018293901367, doi101144gslmem19900120105"
}

@article{doi101016s001282520000026x,
    author = "Streel, Maurice",
    title = "Late Frasnian–Famennian climates based on palynomorph analyses and the question of the Late Devonian glaciations",
    year = "2000",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/s0012-8252(00)00026-x",
    doi = "10.1016/s0012-8252(00)00026-x",
    openalex = "W2040023581",
    references = "alvarez1980extraterrestrial, crossref1982geological, doi101007978364270831215, doi1010160012825273900925, doi1010160016703789901233, doi101017cbo9780511628948, doi101093oso97801985491780010001, doi101126science20844481095, doi101126science27252651155, doi10113000167606198596567defie20co2, doi10113000917613198614535scaia20co2, doi101130spe190, doi101144gslmem19900120101, doi101144gslmem19900120105, doi1013060c9b232b171011d78645000102c1865d, doi1023071485834"
}

Recent paleontological fieldwork in the Upper Devonian Catskill Formation at Red Hill in Clinton County, Pennsylvania, USA, has produced a diverse assemblage of vertebrate fossils including early tetrapods. The tetrapod Hynerpeton bassetti was described from the site in 1994 and a recently recognized partial lower jaw of that taxon is described here. Additionally, this paper describes a new Late Devonian tetrapod, Densignathus rowei new genus and species, based on a well-preserved lower jaw. This new taxon is characterized by dramatic widening of the jaw anterior of the adductor fossa, a pronounced twist in the orientation of ventral margin of the jaw, an uninterrupted exposure of Meckelian bone on the mesial surface, and weakly-developed radiating ornament on the lateral surface of the infradentaries. Although phylogenetic resolution within stem tetrapods is lacking, Densignathus rowei, n. gen. and sp., informs several topics including the sequence of character acquisition in the lower jaw, morphological diversity, and paleoecology of the earliest tetrapods.

@article{doi1016660022336020000740301etjftl20co2,
    author = "Daeschler, Edward B.",
    title = "EARLY TETRAPOD JAWS FROM THE LATE DEVONIAN OF PENNSYLVANIA, USA",
    year = "2000",
    journal = "Journal of Paleontology",
    abstract = "Recent paleontological fieldwork in the Upper Devonian Catskill Formation at Red Hill in Clinton County, Pennsylvania, USA, has produced a diverse assemblage of vertebrate fossils including early tetrapods. The tetrapod Hynerpeton bassetti was described from the site in 1994 and a recently recognized partial lower jaw of that taxon is described here. Additionally, this paper describes a new Late Devonian tetrapod, Densignathus rowei new genus and species, based on a well-preserved lower jaw. This new taxon is characterized by dramatic widening of the jaw anterior of the adductor fossa, a pronounced twist in the orientation of ventral margin of the jaw, an uninterrupted exposure of Meckelian bone on the mesial surface, and weakly-developed radiating ornament on the lateral surface of the infradentaries. Although phylogenetic resolution within stem tetrapods is lacking, Densignathus rowei, n. gen. and sp., informs several topics including the sequence of character acquisition in the lower jaw, morphological diversity, and paleoecology of the earliest tetrapods.",
    url = "https://doi.org/10.1666/0022-3360(2000)074<0301:etjftl>2.0.co;2",
    doi = "10.1666/0022-3360(2000)074<0301:etjftl>2.0.co;2",
    openalex = "W2175900297",
    references = "doi1010160016703782903015, doi101017s0263593300006787, doi10103841710, doi101130spe253p139, doi101144gslmem19900120101, doi104095120614, doi105860choice320949, doi105962bhltitle82144, openalexw319663532"
}

A rock magnetic and SEM study of Devonian carbonates from the Cantabria‐Asturias Region, northern Spain, was undertaken to further our understanding of the pervasive remagnetization of carbonate rocks during the Late Paleozoic, and the mechanism by which these remagnetizations occur. These rocks contain three ancient Late Paleozoic magnetizations. The rock magnetic properties of mineral extracts were compared with those of whole rock chips and “nonmagnetic” residue to deduce magnetic carrier(s) and grain sizes. Hysteresis measurements for rock chips show “typical” wasp‐waisted loops, whereas extract shows typical pseudosingle‐domain‐like (PSD) unrestricted loops. Within all sites, there is a noticeable contribution of superparamagnetic (SP) grains seen in hysteresis properties and low‐temperature magnetization measurements of whole rock chips, whereas a trend away from a strong SP contribution is seen when hysteresis properties of whole rock are compared with those of residue and extract. Consequently, our extraction process (predictably) removes SP grains, while preserving the characteristic fraction of remanence‐carrying material, which behaves like a typical mixture of single‐domain (SD) and PSD magnetite. Paradoxically, the typical “fingerprint” of remagnetized carbonates, as seen in the whole rock data, seems to be a response to abundant SP grains associated with the acquisition of chemical remanent magnetizations (CRM), and not the actual remanence carrying population itself. Scanning electron microscopy (SEM) observations of magnetic extract reveal abundant authigenic Fe‐oxides, characterized as either 10–100 μm Ni‐free spherules or individual 0.1–10 μm euhedral grains. SEM observations of thin sections reveal abundant evidence of fluid flow driven chemical reactions that resulted in formation of new Fe oxide. Such reactions occurred along cracks and grain boundaries and within void space, and are associated with Fe‐rich clay and calcite‐dolomite reactions or as oxidation of Fe‐sulfide framboids. Together, the SEM observations and rock magnetic experiments reveal that the three Late Paleozoic remagnetizations experienced by Cantabria‐Asturias Paleozoic carbonates are CRMs facilitated by the presence of fluids activated during Late Paleozoic Variscan deformation.

@article{doi1010292001jb000200,
    author = "Weil, Arlo Brandon and der Voo, Rob Van",
    title = "Insights into the mechanism for orogen‐related carbonate remagnetization from growth of authigenic Fe‐oxide: A scanning electron microscopy and rock magnetic study of Devonian carbonates from northern Spain",
    year = "2002",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "A rock magnetic and SEM study of Devonian carbonates from the Cantabria‐Asturias Region, northern Spain, was undertaken to further our understanding of the pervasive remagnetization of carbonate rocks during the Late Paleozoic, and the mechanism by which these remagnetizations occur. These rocks contain three ancient Late Paleozoic magnetizations. The rock magnetic properties of mineral extracts were compared with those of whole rock chips and “nonmagnetic” residue to deduce magnetic carrier(s) and grain sizes. Hysteresis measurements for rock chips show “typical” wasp‐waisted loops, whereas extract shows typical pseudosingle‐domain‐like (PSD) unrestricted loops. Within all sites, there is a noticeable contribution of superparamagnetic (SP) grains seen in hysteresis properties and low‐temperature magnetization measurements of whole rock chips, whereas a trend away from a strong SP contribution is seen when hysteresis properties of whole rock are compared with those of residue and extract. Consequently, our extraction process (predictably) removes SP grains, while preserving the characteristic fraction of remanence‐carrying material, which behaves like a typical mixture of single‐domain (SD) and PSD magnetite. Paradoxically, the typical “fingerprint” of remagnetized carbonates, as seen in the whole rock data, seems to be a response to abundant SP grains associated with the acquisition of chemical remanent magnetizations (CRM), and not the actual remanence carrying population itself. Scanning electron microscopy (SEM) observations of magnetic extract reveal abundant authigenic Fe‐oxides, characterized as either 10–100 μm Ni‐free spherules or individual 0.1–10 μm euhedral grains. SEM observations of thin sections reveal abundant evidence of fluid flow driven chemical reactions that resulted in formation of new Fe oxide. Such reactions occurred along cracks and grain boundaries and within void space, and are associated with Fe‐rich clay and calcite‐dolomite reactions or as oxidation of Fe‐sulfide framboids. Together, the SEM observations and rock magnetic experiments reveal that the three Late Paleozoic remagnetizations experienced by Cantabria‐Asturias Paleozoic carbonates are CRMs facilitated by the presence of fluids activated during Late Paleozoic Variscan deformation.",
    url = "https://doi.org/10.1029/2001jb000200",
    doi = "10.1029/2001jb000200",
    openalex = "W2091179707",
    references = "doi10113000917613198311221dmcays20co2"
}

@article{doi101038nature03893,
    author = "Ahlberg, Per and Clack, Jennifer A. and Blom, Henning",
    title = "The axial skeleton of the Devonian tetrapod Ichthyostega",
    year = "2005",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature03893",
    doi = "10.1038/nature03893",
    openalex = "W2039282195",
    references = "doi101111j150239311996tb01839x, doi10182618200376605199601"
}

@article{doi101038nature04639,
    author = "Daeschler, Edward B. and Shubin, Neil H. and Jenkins, Farish A.",
    title = "A Devonian tetrapod-like fish and the evolution of the tetrapod body plan",
    year = "2006",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature04639",
    doi = "10.1038/nature04639",
    openalex = "W2094370487",
    references = "doi101016b9780126709506500187, doi101017s0263593300002340, doi101017s0263593300006787, doi101038nature03893, doi101038nature04119, doi101038nature04637, doi101093oso97801985404720010001, doi101111j109636421991tb00905x, doi101111j150239311996tb01839x, doi101130dnaggnae, doi10182618200376605199601, doi1023071378479, doi1023071447582, doi105860choice402180"
}

Abstract: Occurrences of fossil lungfishes (Dipnoi: Sarcopterygii) in the Famennian Catskill Formation of Pennsylvania are reviewed. A nearly complete dermal skull roof is assigned to a new genus and species, Apatorhynchus opistheretmus. Other recently discovered lungfish specimens include an incomplete postcranium similar to that of the Frasnian genus Fleurantia, a small parasphenoid of uncertain affinities, and isolated toothplates. Previously described dipnoan remains from the Catskill Formation include a partial skull roof of Soederberghia groenlandica, toothplates assigned to several species of Dipterus, a putative rostral or symphysial region placed in the problematic form taxon Ganorhynchus, and sedimentary structures interpreted as burrows. The toothplates attributed to Dipterus are indeterminate and are placed in open nomenclature, while the specimen identified as Ganorhynchus is not convincingly dipnoan. The status of the burrows remains uncertain pending the discovery of lungfish remains within these or similar structures in Catskill deposits. The distinct ichthyofaunas within the Catskill Formation and their lungfish components are briefly reviewed. Lungfishes are found in the Holoptychius ‐ and Bothriolepis ‐dominated faunas common in the Catskill succession, as well as in the compositionally distinctive Red Hill assemblage. Many of the Devonian continental faunas that contain tetrapods also include long‐snouted, denticle‐bearing lungfishes (‘rhynchodipterids’, fleurantiids, or both). The composition of Late Devonian ichthyofaunas may have predictive qualities that will allow researchers to identify localities likely to produce the remains of early tetrapods.

@article{doi101111j14754983200600594x,
    author = "Friedman, Matt and Daeschler, Edward B.",
    title = "LATE DEVONIAN (FAMENNIAN) LUNGFISHES FROM THE CATSKILL FORMATION OF PENNSYLVANIA, USA",
    year = "2006",
    journal = "Palaeontology",
    abstract = "Abstract: Occurrences of fossil lungfishes (Dipnoi: Sarcopterygii) in the Famennian Catskill Formation of Pennsylvania are reviewed. A nearly complete dermal skull roof is assigned to a new genus and species, Apatorhynchus opistheretmus. Other recently discovered lungfish specimens include an incomplete postcranium similar to that of the Frasnian genus Fleurantia, a small parasphenoid of uncertain affinities, and isolated toothplates. Previously described dipnoan remains from the Catskill Formation include a partial skull roof of Soederberghia groenlandica, toothplates assigned to several species of Dipterus, a putative rostral or symphysial region placed in the problematic form taxon Ganorhynchus, and sedimentary structures interpreted as burrows. The toothplates attributed to Dipterus are indeterminate and are placed in open nomenclature, while the specimen identified as Ganorhynchus is not convincingly dipnoan. The status of the burrows remains uncertain pending the discovery of lungfish remains within these or similar structures in Catskill deposits. The distinct ichthyofaunas within the Catskill Formation and their lungfish components are briefly reviewed. Lungfishes are found in the Holoptychius ‐ and Bothriolepis ‐dominated faunas common in the Catskill succession, as well as in the compositionally distinctive Red Hill assemblage. Many of the Devonian continental faunas that contain tetrapods also include long‐snouted, denticle‐bearing lungfishes (‘rhynchodipterids’, fleurantiids, or both). The composition of Late Devonian ichthyofaunas may have predictive qualities that will allow researchers to identify localities likely to produce the remains of early tetrapods.",
    url = "https://doi.org/10.1111/j.1475-4983.2006.00594.x",
    doi = "10.1111/j.1475-4983.2006.00594.x",
    openalex = "W2010589373",
    references = "doi101002jmor1062, doi101016b9780126709506500187, doi101017s0080456800014800, doi101038176126a0, doi101098rstb19940027, doi101126science1094295, doi101126science2655172639, doi1023072413259, doi105281zenodo16682404, openalexw628087051"
}

@article{doi101016jpalwor200912003,
    author = "Lebedev, Oleg A. and Lukševičs, Ervīns and Zakharenko, G.V.",
    title = "Palaeozoogeographical connections of the Devonian vertebrate communities of the Baltica Province. Part II. Late Devonian",
    year = "2009",
    journal = "Palaeoworld",
    url = "https://doi.org/10.1016/j.palwor.2009.12.003",
    doi = "10.1016/j.palwor.2009.12.003",
    openalex = "W2783108934",
    references = "doi101002gj1072, doi101098rspb19880062, doi101111j14754983200600594x, openalexw2208603329"
}

Abstract The remains of Late Devonian tetrapods from the Red Hill locality in Pennsylvania help to elucidate the early stages of tetrapod evolution. Red Hill is a particularly informative site that preserves a diverse fauna and flora within a depositional setting suggesting penecontemporaneous deposition of locally derived material. Here, for the first time, we report on the full suite of early tetrapod remains from Red Hill and consider the implications for tetrapod diversity within the Red Hill ecosystem. Previously described material is reviewed and considered in relation to newly reported specimens. New material described includes isolated skull elements (two jugals, a postorbital, a lacrimal and a coronoid) and postcranial elements (a femur and a gastral scale). The characteristics of many of the Red Hill tetrapod specimens conform to the morphological expectations of Late Devonian forms. Several elements, however, illustrate more derived characteristics and strongly suggest the presence of the oldest known whatcheeriid‐like tetrapod. This study demonstrates the difficulty in making taxonomic associations with isolated remains, even when found in close proximity to one another. Exploration of the characteristics of each element, however, demonstrates the presence of at least three early tetrapod taxa at the Red Hill site.

@article{doi101111j14636395200800361x,
    author = "Daeschler, Edward B. and Clack, Jennifer A. and Shubin, Neil H.",
    title = "Late Devonian tetrapod remains from Red Hill, Pennsylvania, USA: how much diversity?",
    year = "2009",
    journal = "Acta Zoologica",
    abstract = "Abstract The remains of Late Devonian tetrapods from the Red Hill locality in Pennsylvania help to elucidate the early stages of tetrapod evolution. Red Hill is a particularly informative site that preserves a diverse fauna and flora within a depositional setting suggesting penecontemporaneous deposition of locally derived material. Here, for the first time, we report on the full suite of early tetrapod remains from Red Hill and consider the implications for tetrapod diversity within the Red Hill ecosystem. Previously described material is reviewed and considered in relation to newly reported specimens. New material described includes isolated skull elements (two jugals, a postorbital, a lacrimal and a coronoid) and postcranial elements (a femur and a gastral scale). The characteristics of many of the Red Hill tetrapod specimens conform to the morphological expectations of Late Devonian forms. Several elements, however, illustrate more derived characteristics and strongly suggest the presence of the oldest known whatcheeriid‐like tetrapod. This study demonstrates the difficulty in making taxonomic associations with isolated remains, even when found in close proximity to one another. Exploration of the characteristics of each element, however, demonstrates the presence of at least three early tetrapod taxa at the Red Hill site.",
    url = "https://doi.org/10.1111/j.1463-6395.2008.00361.x",
    doi = "10.1111/j.1463-6395.2008.00361.x",
    openalex = "W2016785551",
    references = "doi101017s0263593300002340, doi101017s0263593300006787, doi101017s1464793102006103, doi101086425183, doi101111j109636421985tb01517x, doi101111j109636421995tb00119x, doi101111j150239311996tb01839x, doi101146annurevearth32101802120201, doi1016660022336020000740301etjftl20co2, doi10182618200376605199601, doi105860choice402180"
}

Abstract: Late Devonian (Famennian) tetrapods from the Duncannon Member of the Catskill Formation, near Hyner (Pennsylvania, USA) have been found within palaeosols that offer a new line of evidence for their ancient environments. Hyner has yielded at least two fossil tetrapod species, Hynerpeton basseti and Densignathus rowei. Subhumid Vertisol palaeosols and semiarid Aridisol palaeosols alternate at Hyner, as in other Catskill Formation sedimentary cycles attributed to Milankovitch-eccentricity periods (100 ka). Tetrapods were found in palaeosols of subhumid, not semiarid, phases of 100 ka palaeoclimate cycles. In addition, palaeosols at Hyner record an unusually warm and wet climatic episode compared with other palaeosols of the Catskill Formation, and correlated with the European Annulata black shale event. Tetrapod bones are cracked and disarticulated in red palaeosols of an oxbow lake margin, as if victims of dry-season death, decay, and subaerial weathering. Vegetation-choked swales and floodplains would have afforded shelter from 3–4 m long predatory fish (Hyneria lindae) of open water, and offered food of large dead fish, small live fish, arachnids, myriapods and scorpions. If these early tetrapods lived on land at all, it was during wet seasons of feeding and breeding, rather than fatally dry seasons. Supplementary material: Chemical data are available at http://www.geolsoc.org.uk/SUP18373.

@article{doi101144001676492009022,
    author = "Retallack, Gregory J. and Hunt, R.R. and White, Timothy S.",
    title = "Late Devonian tetrapod habitats indicated by palaeosols in Pennsylvania",
    year = "2009",
    journal = "Journal of the Geological Society",
    abstract = "Abstract: Late Devonian (Famennian) tetrapods from the Duncannon Member of the Catskill Formation, near Hyner (Pennsylvania, USA) have been found within palaeosols that offer a new line of evidence for their ancient environments. Hyner has yielded at least two fossil tetrapod species, Hynerpeton basseti and Densignathus rowei. Subhumid Vertisol palaeosols and semiarid Aridisol palaeosols alternate at Hyner, as in other Catskill Formation sedimentary cycles attributed to Milankovitch-eccentricity periods (100 ka). Tetrapods were found in palaeosols of subhumid, not semiarid, phases of 100 ka palaeoclimate cycles. In addition, palaeosols at Hyner record an unusually warm and wet climatic episode compared with other palaeosols of the Catskill Formation, and correlated with the European Annulata black shale event. Tetrapod bones are cracked and disarticulated in red palaeosols of an oxbow lake margin, as if victims of dry-season death, decay, and subaerial weathering. Vegetation-choked swales and floodplains would have afforded shelter from 3–4 m long predatory fish (Hyneria lindae) of open water, and offered food of large dead fish, small live fish, arachnids, myriapods and scorpions. If these early tetrapods lived on land at all, it was during wet seasons of feeding and breeding, rather than fatally dry seasons. Supplementary material: Chemical data are available at http://www.geolsoc.org.uk/SUP18373.",
    url = "https://doi.org/10.1144/0016-76492009-022",
    doi = "10.1144/0016-76492009-022",
    openalex = "W2056612020",
    references = "doi1010029780470698716, doi1010160016703792901426, doi101017cbo9780511536045, doi101017s0094837300005820, doi1010719781486304646, doi101098rstb19980195, doi102475ajs2914377, openalexw2890624634, openalexw2989049194"
}

@article{doi101016jpalaeo201010040,
    author = "Retallack, Gregory J. and Huang, Chengmin",
    title = "Ecology and evolution of Devonian trees in New York, USA",
    year = "2010",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2010.10.040",
    doi = "10.1016/j.palaeo.2010.10.040",
    openalex = "W2073391272",
    references = "banks1985the, bridge1994marine, doi1010029780470698716, doi1010029781118663615oth1, doi1010160016703792901426, doi101016c20201040965, doi101016jearscirev200903004, doi101016jpalaeo200910010, doi101038nature08213, doi1010719781486304646, doi101098rstb19980195, doi101144001676492009022, openalexw2890624634"
}

@article{doi101038nature08623,
    author = "Niedźwiedzki, Grzegorz and Szrek, Piotr and Narkiewicz, Katarzyna and Narkiewicz, Marek and Ahlberg, Per",
    title = "Tetrapod trackways from the early Middle Devonian period of Poland",
    year = "2010",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature08623",
    doi = "10.1038/nature08623",
    openalex = "W1973657142",
    references = "doi101016s0031018296001423, doi101017s0263593300002340, doi101017s0263593300006787, doi10103827421, doi101038347066a0, doi101038nature04637, doi101038nature04639, doi101038nature07855, doi101111j109636421995tb00119x, doi1016660022336020000740301etjftl20co2"
}

The Devonian marks a critical stage in the early evolution of vertebrates: It opens with an unprecedented diversity of fishes and closes with the earliest evidence of limbed tetrapods. However, the latter part of the Devonian has also been characterized as a period of global biotic crisis marked by two large extinction pulses: a “Big Five” mass extinction event at the Frasnian-Famennian stage boundary (374 Ma) and the less well-documented Hangenberg event some 15 million years later at the Devonian-Carboniferous boundary (359 Ma). Here, we report the results of a wide-ranging analysis of the impact of these events on early vertebrate evolution, which was obtained from a database of vertebrate occurrences sampling over 1,250 taxa from 66 localities spanning Givetian to Serpukhovian stages (391 to 318 Ma). We show that major vertebrate clades suffered acute and systematic effects centered on the Hangenberg extinction involving long-term losses of over 50% of diversity and the restructuring of vertebrate ecosystems worldwide. Marine and nonmarine faunas were equally affected, precluding the existence of environmental refugia. The subsequent recovery of previously diverse groups (including placoderms, sarcopterygian fish, and acanthodians) was minimal. Tetrapods, actinopterygians, and chondrichthyans, all scarce within the Devonian, undergo large diversification events in the aftermath of the extinction, dominating all subsequent faunas. The Hangenberg event represents a previously unrecognized bottleneck in the evolutionary history of vertebrates as a whole and a historical contingency that shaped the roots of modern biodiversity.

@article{doi101073pnas0914000107,
    author = "Sallan, Lauren and Coates, Michael I.",
    title = "End-Devonian extinction and a bottleneck in the early evolution of modern jawed vertebrates",
    year = "2010",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The Devonian marks a critical stage in the early evolution of vertebrates: It opens with an unprecedented diversity of fishes and closes with the earliest evidence of limbed tetrapods. However, the latter part of the Devonian has also been characterized as a period of global biotic crisis marked by two large extinction pulses: a “Big Five” mass extinction event at the Frasnian-Famennian stage boundary (374 Ma) and the less well-documented Hangenberg event some 15 million years later at the Devonian-Carboniferous boundary (359 Ma). Here, we report the results of a wide-ranging analysis of the impact of these events on early vertebrate evolution, which was obtained from a database of vertebrate occurrences sampling over 1,250 taxa from 66 localities spanning Givetian to Serpukhovian stages (391 to 318 Ma). We show that major vertebrate clades suffered acute and systematic effects centered on the Hangenberg extinction involving long-term losses of over 50\% of diversity and the restructuring of vertebrate ecosystems worldwide. Marine and nonmarine faunas were equally affected, precluding the existence of environmental refugia. The subsequent recovery of previously diverse groups (including placoderms, sarcopterygian fish, and acanthodians) was minimal. Tetrapods, actinopterygians, and chondrichthyans, all scarce within the Devonian, undergo large diversification events in the aftermath of the extinction, dominating all subsequent faunas. The Hangenberg event represents a previously unrecognized bottleneck in the evolutionary history of vertebrates as a whole and a historical contingency that shaped the roots of modern biodiversity.",
    url = "https://doi.org/10.1073/pnas.0914000107",
    doi = "10.1073/pnas.0914000107",
    openalex = "W2053959738",
    references = "doi101002gj1072, doi101038347066a0, doi101098rspb20071370, doi105860choice320949"
}

Abstract Alluvial floodplains were a critical setting during the Late Devonian for the evolution of terrestriality among plants, invertebrate and vertebrates. The Red Hill site in Pennsylvania, US, provides a range of information about the physical and biotic setting of a floodplain ecosystem along the southern margin of the Euramerican landmass during the late Famennian age. An avulsion model for floodplain sedimentation is favoured in which a variety of inter-channel depositional settings formed a wide range of aquatic and terrestrial habitats. The Red Hill flora demonstrates ecological partitioning of the floodplain landscape at a high taxonomic level. In addition to progymnosperm forests, lycopsid wetlands and zygopterid fern glades, the flora includes patches of early spermatophytes occupying sites disturbed by fires. The Red Hill fauna illustrates the development of a diverse penecontemporaneous community including terrestrial invertebrates and a wide range of vertebrates that were living within aquatic habitats. Among the vertebrates are several limbed tetrapodomorphs that inhabited the burgeoning shallow water habitats on the floodplain.

@article{doi101144sp33910,
    author = "Cressler, Walter and Daeschler, Edward B. and Slingerland, Rudy and Peterson, Daniel Adam",
    title = "Terrestrialization in the Late Devonian: a palaeoecological overview of the Red Hill site, Pennsylvania, USA",
    year = "2010",
    journal = "Geological Society London Special Publications",
    abstract = "Abstract Alluvial floodplains were a critical setting during the Late Devonian for the evolution of terrestriality among plants, invertebrate and vertebrates. The Red Hill site in Pennsylvania, US, provides a range of information about the physical and biotic setting of a floodplain ecosystem along the southern margin of the Euramerican landmass during the late Famennian age. An avulsion model for floodplain sedimentation is favoured in which a variety of inter-channel depositional settings formed a wide range of aquatic and terrestrial habitats. The Red Hill flora demonstrates ecological partitioning of the floodplain landscape at a high taxonomic level. In addition to progymnosperm forests, lycopsid wetlands and zygopterid fern glades, the flora includes patches of early spermatophytes occupying sites disturbed by fires. The Red Hill fauna illustrates the development of a diverse penecontemporaneous community including terrestrial invertebrates and a wide range of vertebrates that were living within aquatic habitats. Among the vertebrates are several limbed tetrapodomorphs that inhabited the burgeoning shallow water habitats on the floodplain.",
    url = "https://doi.org/10.1144/sp339.10",
    doi = "10.1144/sp339.10",
    openalex = "W2010672566",
    references = "doi101038nature04639, doi101093oso97801985404720010001, doi101098rstb19980195, doi101111j136530911989tb00817x, doi101111j14636395200800361x, doi101144gslmem19900120101, doi101146annurevearth32101802120201, doi1023071485834, doi1023073243920, doi1023075209, doi104095120614"
}

@article{doi101016jepsl201108042,
    author = "Hir, Guillaume Le and Donnadieu, Yannick and Goddéris, Yves and Meyer‐Berthaud, Brigitte and Ramstein, Gilles and Blakey, Ronald C.",
    title = "The climate change caused by the land plant invasion in the Devonian",
    year = "2011",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/j.epsl.2011.08.042",
    doi = "10.1016/j.epsl.2011.08.042",
    openalex = "W2040828597",
    references = "doi101144sp33910, doi101144sp3396, doi1023073515409"
}

@incollection{doi101016b9780444594259000226,
    author = "Becker, Ralph Thomas and Gradstein, Felix M. and Hammer, Øyvind",
    title = "The Devonian Period",
    year = "2012",
    booktitle = "Elsevier eBooks",
    url = "https://doi.org/10.1016/b978-0-444-59425-9.00022-6",
    doi = "10.1016/b978-0-444-59425-9.00022-6",
    openalex = "W3010207324",
    references = "doi1010079781402068065, doi1011300091761319808281przfld20co2, doi105860choice402180, doi105860choice503274, openalexw1252084533"
}

@article{doi101016japgeochem201210002,
    author = "Haluszczak, Lara O. and Rose, Arthur and Kump, Lee R.",
    title = "Geochemical evaluation of flowback brine from Marcellus gas wells in Pennsylvania, USA",
    year = "2012",
    journal = "Applied Geochemistry",
    url = "https://doi.org/10.1016/j.apgeochem.2012.10.002",
    doi = "10.1016/j.apgeochem.2012.10.002",
    openalex = "W2146219427"
}

@article{doi101038nature10819,
    author = "Stein, William E. and Berry, Christopher M. and Hernick, Linda VanAller and Mannolini, Frank",
    title = "Surprisingly complex community discovered in the mid-Devonian fossil forest at Gilboa",
    year = "2012",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature10819",
    doi = "10.1038/nature10819",
    openalex = "W2020361426",
    references = "banks1985the, bridge1994marine, doi101016jpalaeo201010040, doi10103819516, doi101038nature05705, doi1011302006239901, doi101130g304431, doi1013062dc4092c0e4711d78643000102c1865d, doi1016400002844420010910074ele20co2, doi1023072399754, doi1023073515409, doi107312gens11160013"
}

@article{doi101038nature11281,
    author = "Garrouste, Romain and Clément, Gaël and Nel, Patricia and Engel, Michael S. and Grandcolas, Philippe and D'Haese, Cyrille A. and Lagebro, Linda and Denayer, Julien and Guériau, Pierre and Lafaite, Patrick and Olive, Sébastien and Prestianni, Cyrille and Nel, André",
    title = "A complete insect from the Late Devonian period",
    year = "2012",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature11281",
    doi = "10.1038/nature11281",
    openalex = "W2070388731",
    references = "doi101073pnas1117332109"
}

The debate surrounding the safety of shale gas development in the Appalachian Basin has generated increased awareness of drinking water quality in rural communities. Concerns include the potential for migration of stray gas, metal-rich formation brines, and hydraulic fracturing and/or flowback fluids to drinking water aquifers. A critical question common to these environmental risks is the hydraulic connectivity between the shale gas formations and the overlying shallow drinking water aquifers. We present geochemical evidence from northeastern Pennsylvania showing that pathways, unrelated to recent drilling activities, exist in some locations between deep underlying formations and shallow drinking water aquifers. Integration of chemical data (Br, Cl, Na, Ba, Sr, and Li) and isotopic ratios ((87)Sr/(86)Sr, (2)H/H, (18)O/(16)O, and (228)Ra/(226)Ra) from this and previous studies in 426 shallow groundwater samples and 83 northern Appalachian brine samples suggest that mixing relationships between shallow ground water and a deep formation brine causes groundwater salinization in some locations. The strong geochemical fingerprint in the salinized (Cl > 20 mg/L) groundwater sampled from the Alluvium, Catskill, and Lock Haven aquifers suggests possible migration of Marcellus brine through naturally occurring pathways. The occurrences of saline water do not correlate with the location of shale-gas wells and are consistent with reported data before rapid shale-gas development in the region; however, the presence of these fluids suggests conductive pathways and specific geostructural and/or hydrodynamic regimes in northeastern Pennsylvania that are at increased risk for contamination of shallow drinking water resources, particularly by fugitive gases, because of natural hydraulic connections to deeper formations.

@article{doi101073pnas1121181109,
    author = "Warner, Nathaniel R. and Jackson, Robert B. and Darrah, Thomas H. and Osborn, Stephen G. and Down, Adrian and Zhao, Kaiguang and White, Alissa and Vengosh, Avner",
    title = "Geochemical evidence for possible natural migration of Marcellus Formation brine to shallow aquifers in Pennsylvania",
    year = "2012",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The debate surrounding the safety of shale gas development in the Appalachian Basin has generated increased awareness of drinking water quality in rural communities. Concerns include the potential for migration of stray gas, metal-rich formation brines, and hydraulic fracturing and/or flowback fluids to drinking water aquifers. A critical question common to these environmental risks is the hydraulic connectivity between the shale gas formations and the overlying shallow drinking water aquifers. We present geochemical evidence from northeastern Pennsylvania showing that pathways, unrelated to recent drilling activities, exist in some locations between deep underlying formations and shallow drinking water aquifers. Integration of chemical data (Br, Cl, Na, Ba, Sr, and Li) and isotopic ratios ((87)Sr/(86)Sr, (2)H/H, (18)O/(16)O, and (228)Ra/(226)Ra) from this and previous studies in 426 shallow groundwater samples and 83 northern Appalachian brine samples suggest that mixing relationships between shallow ground water and a deep formation brine causes groundwater salinization in some locations. The strong geochemical fingerprint in the salinized (Cl > 20 mg/L) groundwater sampled from the Alluvium, Catskill, and Lock Haven aquifers suggests possible migration of Marcellus brine through naturally occurring pathways. The occurrences of saline water do not correlate with the location of shale-gas wells and are consistent with reported data before rapid shale-gas development in the region; however, the presence of these fluids suggests conductive pathways and specific geostructural and/or hydrodynamic regimes in northeastern Pennsylvania that are at increased risk for contamination of shallow drinking water resources, particularly by fugitive gases, because of natural hydraulic connections to deeper formations.",
    url = "https://doi.org/10.1073/pnas.1121181109",
    doi = "10.1073/pnas.1121181109",
    openalex = "W2149397149"
}

Pore systems hosted dominantly within organic matter (OM) are widely documented in gas shales (e.g., Ambrose et al., 2010; Curtis et al., 2011a; Curtis et al., 2011b; Loucks et al., 2009; Passey et al., 2010; Sondergeld et al., 2010) and siliciclastic mudrocks of the Marcellus Formation in northern Pennsylvania, USA provide an excellent example.

@article{doi1039972214460920143942,
    author = "Milliken, K.L. and Rudnicki, M.D. and Awwiller, David",
    title = "Form and Distribution of Organic Matter-Hosted Pores, Marcellus Formation (Devonian), Pennsylvania, USA",
    year = "2012",
    journal = "Proceedings",
    abstract = "Pore systems hosted dominantly within organic matter (OM) are widely documented in gas shales (e.g., Ambrose et al., 2010; Curtis et al., 2011a; Curtis et al., 2011b; Loucks et al., 2009; Passey et al., 2010; Sondergeld et al., 2010) and siliciclastic mudrocks of the Marcellus Formation in northern Pennsylvania, USA provide an excellent example.",
    url = "https://doi.org/10.3997/2214-4609.20143942",
    doi = "10.3997/2214-4609.20143942",
    openalex = "W2078851287"
}

Abstract. A Devonian magnetic susceptibility (MS) record obtained on limestones ranging from the Uppermost-Eifelian to the Lower-Givetian and located on the southern border of the Dinant Synclinorium in Belgium was selected for time-series analysis. In these carbonate ramp and platform deposits, spectral analyses highlight persistent, high-frequency cycles in both the MS-signal and the microfacies curve, reflecting environmental and climate changes. These metre-scale variations in the MS-signal are interpreted as changes in the flux of magnetic minerals towards the marine system, most likely controlled by monsoon rainfall-intensity. By combining chrono- and biostratigraphic information with theoretical knowledge of sedimentation rates in different depositional environments, these cycles are interpreted as astronomically driven and dominated by precession. It is hypothesized that during precession minima (longitude of the perihelion ≈270°) the trans-equatorial pressure gradient reaches a maximum and intensifies the northeasterly monsoonal circulation. The consequent increase in moisture transport towards the continent leads to enhanced precipitation and runoff, which, in turn, induces a higher flux of detrital material – including magnetic minerals responsible for the MS-signal – towards the marine system. Moreover, this unique high-resolution climate signal reveals half-precessional cycles. These cycles suggest that during precession maxima (longitude of the perihelion ≈90°) southeasterly monsoonal circulation strengthened due to an increased inter-hemispheric pressure gradient.

@article{doi105194cp83372012,
    author = "Vleeschouwer, David De and Silva, Anne‐Christine Da and Boulvain, Frédéric and Crucifix, Michel and Claeys, Philippe",
    title = "Precessional and half-precessional climate forcing of Mid-Devonian monsoon-like dynamics",
    year = "2012",
    journal = "Climate of the past",
    abstract = "Abstract. A Devonian magnetic susceptibility (MS) record obtained on limestones ranging from the Uppermost-Eifelian to the Lower-Givetian and located on the southern border of the Dinant Synclinorium in Belgium was selected for time-series analysis. In these carbonate ramp and platform deposits, spectral analyses highlight persistent, high-frequency cycles in both the MS-signal and the microfacies curve, reflecting environmental and climate changes. These metre-scale variations in the MS-signal are interpreted as changes in the flux of magnetic minerals towards the marine system, most likely controlled by monsoon rainfall-intensity. By combining chrono- and biostratigraphic information with theoretical knowledge of sedimentation rates in different depositional environments, these cycles are interpreted as astronomically driven and dominated by precession. It is hypothesized that during precession minima (longitude of the perihelion ≈270°) the trans-equatorial pressure gradient reaches a maximum and intensifies the northeasterly monsoonal circulation. The consequent increase in moisture transport towards the continent leads to enhanced precipitation and runoff, which, in turn, induces a higher flux of detrital material – including magnetic minerals responsible for the MS-signal – towards the marine system. Moreover, this unique high-resolution climate signal reveals half-precessional cycles. These cycles suggest that during precession maxima (longitude of the perihelion ≈90°) southeasterly monsoonal circulation strengthened due to an increased inter-hemispheric pressure gradient.",
    url = "https://doi.org/10.5194/cp-8-337-2012",
    doi = "10.5194/cp-8-337-2012",
    openalex = "W2105392646",
    references = "doi101144sp33910"
}

@article{doi101016jmarpetgeo201306012,
    author = "Silva, Anne‐Christine Da and Vleeschouwer, David De and Boulvain, Frédéric and Claeys, Philippe and Fagel, Nathalie and Humblet, Marc and Mabille, Cédric and Michel, Jennifer and Abadi, Mehrdad Sardar and Pas, Damien and Dekkers, Mark J.",
    title = "Magnetic susceptibility as a high-resolution correlation tool and as a climatic proxy in Paleozoic rocks – Merits and pitfalls: Examples from the Devonian in Belgium",
    year = "2013",
    journal = "Marine and Petroleum Geology",
    url = "https://doi.org/10.1016/j.marpetgeo.2013.06.012",
    doi = "10.1016/j.marpetgeo.2013.06.012",
    openalex = "W2156125246",
    references = "doi101046j0956540x200001349x, doi101144sp37115, doi102110jsr2010093"
}

Testing of 1701 water wells in northeastern Pennsylvania shows that methane is ubiquitous in groundwater, with higher concentrations observed in valleys vs. upland areas and in association with calcium-sodium-bicarbonate, sodium-bicarbonate, and sodium-chloride rich waters--indicating that, on a regional scale, methane concentrations are best correlated to topographic and hydrogeologic features, rather than shale-gas extraction. In addition, our assessment of isotopic and molecular analyses of hydrocarbon gases in the Dimock Township suggest that gases present in local water wells are most consistent with Middle and Upper Devonian gases sampled in the annular spaces of local gas wells, as opposed to Marcellus Production gas. Combined, these findings suggest that the methane concentrations in Susquehanna County water wells can be explained without the migration of Marcellus shale gas through fractures, an observation that has important implications for understanding the nature of risks associated with shale-gas extraction.

@article{doi101111gwat12056,
    author = "Molofsky, Lisa J. and Connor, John A. and Wylie, Albert S. and Wagner, Tom and Farhat, Shahla K.",
    title = "Evaluation of Methane Sources in Groundwater in Northeastern Pennsylvania",
    year = "2013",
    journal = "Ground Water",
    abstract = "Testing of 1701 water wells in northeastern Pennsylvania shows that methane is ubiquitous in groundwater, with higher concentrations observed in valleys vs. upland areas and in association with calcium-sodium-bicarbonate, sodium-bicarbonate, and sodium-chloride rich waters--indicating that, on a regional scale, methane concentrations are best correlated to topographic and hydrogeologic features, rather than shale-gas extraction. In addition, our assessment of isotopic and molecular analyses of hydrocarbon gases in the Dimock Township suggest that gases present in local water wells are most consistent with Middle and Upper Devonian gases sampled in the annular spaces of local gas wells, as opposed to Marcellus Production gas. Combined, these findings suggest that the methane concentrations in Susquehanna County water wells can be explained without the migration of Marcellus shale gas through fractures, an observation that has important implications for understanding the nature of risks associated with shale-gas extraction.",
    url = "https://doi.org/10.1111/gwat.12056",
    doi = "10.1111/gwat.12056",
    openalex = "W2166083971",
    references = "doi101130mem158p161"
}

Abstract The evolution of porosity in shales with increasing maturity was examined in a suite of five New Albany Shale samples spanning a maturity range from immature (vitrinite reflectance, Ro 0.35%) to postmature (Ro 1.41%). Devonian to lower Mississippian New Albany Shale samples from the Illinois Basin used in this study contain marine type II kerogen having total organic carbon contents from 1.2 to 13.0 wt. %. Organic petrology, CO2 and N2 low-pressure adsorption, and mercury intrusion capillary pressure techniques were used to quantify pore volumes, pore sizes, and pore-size distributions. Increasing maturity of the New Albany Shale is paralleled by many changes in the characteristics of porosity. The total porosity of 9.1 vol. % in immature New Albany Shale decreases to 1.5 vol. % in the late mature sample, whereas total pore volumes decrease from 0.0365 to 0.0059 cm3/g in the same sequence. Reversing the trend at even higher maturity, the postmature New Albany Shale exhibits higher porosity and larger total pore volumes compared to the late mature sample. With increasing maturity, changes in total porosity and total pore volumes are accompanied by changes in pore-size distributions and relative proportions of micropores, mesopores, and macropores. Porosity-related variances are directly related to differences in the amount and character of the organic matter and mineralogical composition, but maturity exerts the dominant control upon these characteristics. We conclude that organic matter transformation due to hydrocarbon generation and migration is a pivotal cause of the observed porosity differences.

@article{doi10130604011312194,
    author = "Mastalerz, María and Schimmelmann, Arndt and Drobniak, Agnieszka and Chen, Yanyan",
    title = "Porosity of Devonian and Mississippian New Albany Shale across a maturation gradient: Insights from organic petrology, gas adsorption, and mercury intrusion",
    year = "2013",
    journal = "AAPG Bulletin",
    abstract = "Abstract The evolution of porosity in shales with increasing maturity was examined in a suite of five New Albany Shale samples spanning a maturity range from immature (vitrinite reflectance, Ro 0.35\%) to postmature (Ro 1.41\%). Devonian to lower Mississippian New Albany Shale samples from the Illinois Basin used in this study contain marine type II kerogen having total organic carbon contents from 1.2 to 13.0 wt. \%. Organic petrology, CO2 and N2 low-pressure adsorption, and mercury intrusion capillary pressure techniques were used to quantify pore volumes, pore sizes, and pore-size distributions. Increasing maturity of the New Albany Shale is paralleled by many changes in the characteristics of porosity. The total porosity of 9.1 vol. \% in immature New Albany Shale decreases to 1.5 vol. \% in the late mature sample, whereas total pore volumes decrease from 0.0365 to 0.0059 cm3/g in the same sequence. Reversing the trend at even higher maturity, the postmature New Albany Shale exhibits higher porosity and larger total pore volumes compared to the late mature sample. With increasing maturity, changes in total porosity and total pore volumes are accompanied by changes in pore-size distributions and relative proportions of micropores, mesopores, and macropores. Porosity-related variances are directly related to differences in the amount and character of the organic matter and mineralogical composition, but maturity exerts the dominant control upon these characteristics. We conclude that organic matter transformation due to hydrocarbon generation and migration is a pivotal cause of the observed porosity differences.",
    url = "https://doi.org/10.1306/04011312194",
    doi = "10.1306/04011312194",
    openalex = "W2110830197",
    references = "doi10130607231212048, doi10130694885688170411d78645000102c1865d"
}

Abstract The Marcellus Formation of Pennsylvania represents an outstanding example of an organic matter (OM)–hosted pore system; most pores detectable by field-emission scanning electron microscopy (FE-SEM) are associated with OM instead of mineral matrix. In the two wells studied here, total organic carbon (TOC) content is a stronger control on OM-hosted porosity than is thermal maturity. The two study wells span a maturity from late wet gas (vitrinite reflectance [Ro], ∼1.0%) to dry gas (Ro, ∼2.1%). Samples with a TOC less than 5.5 wt. % display a positive correlation between TOC and porosity, but samples with a TOC greater than 5.5 wt. % display little or no increase in porosity with a further increasing TOC. In a subset of samples (14) across a range of TOC (2.3–13.6 wt. %), the pore volume detectable by FE-SEM is a small fraction of total porosity, ranging from 2 to 32% of the helium porosity. Importantly, the FE-SEM–visible porosity in OM decreases significantly with increasing TOC, diminishing from 30% of OM volume to less than 1% of OM volume across the range of TOC. The morphology and size of OM-hosted pores also vary systematically with TOC. The interpretation of this anticorrelation between OM content and SEM-visible pores remains uncertain. Samples with the lowest OM porosity (higher TOC) may represent gas expulsion (pore collapse) that was more complete as a consequence of greater OM connectivity and framework compaction, whereas samples with higher OM porosity (lower TOC) correspond to rigid mineral frameworks that inhibited compactional expulsion of methane-filled bubbles. Alternatively, higher TOC samples may contain OM (low initial hydrogen index, relatively unreactive) that is less prone to development of FE-SEM–detectable pores. In this interpretation, OM type, controlled by sequence-stratigraphic position, is a factor in determining pore-size distribution.

@article{doi10130607231212048,
    author = "Milliken, K.L. and Rudnicki, M.D. and Awwiller, David and Zhang, Tongwei",
    title = "Organic matter–hosted pore system, Marcellus Formation (Devonian), Pennsylvania",
    year = "2013",
    journal = "AAPG Bulletin",
    abstract = "Abstract The Marcellus Formation of Pennsylvania represents an outstanding example of an organic matter (OM)–hosted pore system; most pores detectable by field-emission scanning electron microscopy (FE-SEM) are associated with OM instead of mineral matrix. In the two wells studied here, total organic carbon (TOC) content is a stronger control on OM-hosted porosity than is thermal maturity. The two study wells span a maturity from late wet gas (vitrinite reflectance [Ro], ∼1.0\%) to dry gas (Ro, ∼2.1\%). Samples with a TOC less than 5.5 wt. \% display a positive correlation between TOC and porosity, but samples with a TOC greater than 5.5 wt. \% display little or no increase in porosity with a further increasing TOC. In a subset of samples (14) across a range of TOC (2.3–13.6 wt. \%), the pore volume detectable by FE-SEM is a small fraction of total porosity, ranging from 2 to 32\% of the helium porosity. Importantly, the FE-SEM–visible porosity in OM decreases significantly with increasing TOC, diminishing from 30\% of OM volume to less than 1\% of OM volume across the range of TOC. The morphology and size of OM-hosted pores also vary systematically with TOC. The interpretation of this anticorrelation between OM content and SEM-visible pores remains uncertain. Samples with the lowest OM porosity (higher TOC) may represent gas expulsion (pore collapse) that was more complete as a consequence of greater OM connectivity and framework compaction, whereas samples with higher OM porosity (lower TOC) correspond to rigid mineral frameworks that inhibited compactional expulsion of methane-filled bubbles. Alternatively, higher TOC samples may contain OM (low initial hydrogen index, relatively unreactive) that is less prone to development of FE-SEM–detectable pores. In this interpretation, OM type, controlled by sequence-stratigraphic position, is a factor in determining pore-size distribution.",
    url = "https://doi.org/10.1306/07231212048",
    doi = "10.1306/07231212048",
    openalex = "W2158897778",
    references = "doi1010079783642964466, doi1010160166516289901134, doi101016s0166516298000305, doi101126science1066611, doi10130603301110145, doi10130608171111061, doi102110jsr2009092, doi102118131350ms, doi102118131771ms, openalexw296468733"
}

@article{doi101016jgloplacha201406002,
    author = "Vleeschouwer, David De and Crucifix, Michel and Bounceur, Nabila and Claeys, Philippe",
    title = "The impact of astronomical forcing on the Late Devonian greenhouse climate",
    year = "2014",
    journal = "Global and Planetary Change",
    url = "https://doi.org/10.1016/j.gloplacha.2014.06.002",
    doi = "10.1016/j.gloplacha.2014.06.002",
    openalex = "W1996024839",
    references = "doi101144sp33910"
}

SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

@article{doi101080027246342014877474,
    author = "Mondéjar‐Fernández, Jorge and Clément, Gaël and Sanchez, Sophie",
    title = "New insights into the scales of the Devonian tetrapod Tulerpeton curtum Lebedev, 1984",
    year = "2014",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP",
    url = "https://doi.org/10.1080/02724634.2014.877474",
    doi = "10.1080/02724634.2014.877474",
    openalex = "W2167297265",
    references = "doi1010079781489957405, doi101017s0263593300006787, doi101029sc005p0175, doi101038nature04639, doi101038nature11124, doi101093oso97801985404720010001, doi101111j14636395200800361x, doi101111j14697580200801043x, doi1023071292217, doi1023072413058, doi105860choice503274"
}

@article{doi101016japgeochem201504011,
    author = "Akob, Denise M. and Cozzarelli, Isabelle M. and Dunlap, Darren S. and Rowan, Elisabeth L. and Lorah, Michelle M.",
    title = "Organic and inorganic composition and microbiology of produced waters from Pennsylvania shale gas wells",
    year = "2015",
    journal = "Applied Geochemistry",
    url = "https://doi.org/10.1016/j.apgeochem.2015.04.011",
    doi = "10.1016/j.apgeochem.2015.04.011",
    openalex = "W2028004305",
    references = "doi10130607071413146"
}

Qiao, T. & Zhu, M., XX.XX.2015. A new Early Devonian lungfish from Guangxi, China, and its palaeogeographic significance. Alcheringa 39, xxx–xxx. ISSN 0311-5518A new species of Cathlorhynchus (Dipnorhynchidae, Dipnoi) is described based on a mandible from the marine Yukiang Formation (early Emsian, Early Devonian) of Guangxi, southern China. It resembles the type species of Cathlorhynchus, C. trismodipterus, in that the anterior portion of the internal median septum terminates abruptly and does not contact dermal bones ventrally. The new Chinese form, together with Erikia jarviki from the Emsian of Yunnan, southern China, confirms the occurrence of the Dipnorhynchus lineage outside Australia. Coupled with the distribution of Westollrhynchus, Ichnomylax and Jessenia, we propose that the Dipnorhynchus lineage was dispersed widely during the early Emsian, corroborating the trans-Panthalassic distribution of early sarcopterygians. Tuo Qiao [qiaotuo@ivpp.ac.cn] and Min Zhu [zhumin@ivpp.ac.cn], Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, PO Box 643, Beijing 100044, PR China.

@article{doi1010800311551820151015819,
    author = "Qiao, Tuo and Zhu, Min",
    title = "A new Early Devonian lungfish from Guangxi, China, and its palaeogeographic significance",
    year = "2015",
    journal = "Alcheringa An Australasian Journal of Palaeontology",
    abstract = "Qiao, T. \& Zhu, M., XX.XX.2015. A new Early Devonian lungfish from Guangxi, China, and its palaeogeographic significance. Alcheringa 39, xxx–xxx. ISSN 0311-5518A new species of Cathlorhynchus (Dipnorhynchidae, Dipnoi) is described based on a mandible from the marine Yukiang Formation (early Emsian, Early Devonian) of Guangxi, southern China. It resembles the type species of Cathlorhynchus, C. trismodipterus, in that the anterior portion of the internal median septum terminates abruptly and does not contact dermal bones ventrally. The new Chinese form, together with Erikia jarviki from the Emsian of Yunnan, southern China, confirms the occurrence of the Dipnorhynchus lineage outside Australia. Coupled with the distribution of Westollrhynchus, Ichnomylax and Jessenia, we propose that the Dipnorhynchus lineage was dispersed widely during the early Emsian, corroborating the trans-Panthalassic distribution of early sarcopterygians. Tuo Qiao [qiaotuo@ivpp.ac.cn] and Min Zhu [zhumin@ivpp.ac.cn], Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, PO Box 643, Beijing 100044, PR China.",
    url = "https://doi.org/10.1080/03115518.2015.1015819",
    doi = "10.1080/03115518.2015.1015819",
    openalex = "W2073462874",
    references = "doi101111j14754983200600594x"
}

Abstract Romer's Gap, the interval following the end‐Devonian extinction event, has been described as a post‐extinction trough for vertebrates. It is a time roughly equivalent to the Tournaisian stage of the early Carboniferous and has been characterized by a lull in diversity of survivors. Lungfish typified this description. One species was known from one locality. Recently, a diverse collection of lungfish tooth plates, representing seven new forms, was recovered from new Tournaisian vertebrate localities in northern Britain. They display a range of previously unknown morphologies, with tooth shape and wear patterns not seen in other post‐Devonian forms. A comparison of tooth ridge number and tooth ridge angle in lungfishes from the Famennian, Tournaisian and Visean reveals marked differences between late Devonian and early Carboniferous taxa. The most common tooth plate shape in the Famennian is absent from our sample of Tournaisian taxa. Two completely new shapes have evolved, one with a relatively low tooth ridge angle, no greater than 40°, in which most of the tooth ridges are essentially parallel, and the other with a much higher tooth ridge angle of up to 180° where the tooth ridges are highly divergent. This high level of morphological diversity over a narrow time period suggests that, following the end‐Devonian extinction, gaps in ecospace left by the extinction of major groups of fishes were exploited by a previously unrecorded radiation of lungfishes. Whilst taxonomic diversity of lungfishes declined following the end‐Devonian extinction, recovery and diversification among tooth‐plated forms was rapid, and morphological disparity among these forms subsequently increased. Contrary to previous assumptions, morphological disparity among lungfish did not decline until much later in the Carboniferous.

@article{doi101111pala12203,
    author = "Smithson, Timothy R. and Richards, Kelly R. and Clack, Jennifer A.",
    title = "Lungfish diversity in Romer's Gap: reaction to the end‐Devonian extinction",
    year = "2015",
    journal = "Palaeontology",
    abstract = "Abstract Romer's Gap, the interval following the end‐Devonian extinction event, has been described as a post‐extinction trough for vertebrates. It is a time roughly equivalent to the Tournaisian stage of the early Carboniferous and has been characterized by a lull in diversity of survivors. Lungfish typified this description. One species was known from one locality. Recently, a diverse collection of lungfish tooth plates, representing seven new forms, was recovered from new Tournaisian vertebrate localities in northern Britain. They display a range of previously unknown morphologies, with tooth shape and wear patterns not seen in other post‐Devonian forms. A comparison of tooth ridge number and tooth ridge angle in lungfishes from the Famennian, Tournaisian and Visean reveals marked differences between late Devonian and early Carboniferous taxa. The most common tooth plate shape in the Famennian is absent from our sample of Tournaisian taxa. Two completely new shapes have evolved, one with a relatively low tooth ridge angle, no greater than 40°, in which most of the tooth ridges are essentially parallel, and the other with a much higher tooth ridge angle of up to 180° where the tooth ridges are highly divergent. This high level of morphological diversity over a narrow time period suggests that, following the end‐Devonian extinction, gaps in ecospace left by the extinction of major groups of fishes were exploited by a previously unrecorded radiation of lungfishes. Whilst taxonomic diversity of lungfishes declined following the end‐Devonian extinction, recovery and diversification among tooth‐plated forms was rapid, and morphological disparity among these forms subsequently increased. Contrary to previous assumptions, morphological disparity among lungfish did not decline until much later in the Carboniferous.",
    url = "https://doi.org/10.1111/pala.12203",
    doi = "10.1111/pala.12203",
    openalex = "W2110215851",
    references = "doi101111j14754983200600594x"
}

Abstract The global Hangenberg Crisis near the Devonian–Carboniferous boundary (DCB) represents a mass extinction that is of the same scale as the so-called ‘Big Five’ first-order Phanerozoic events. It played an important role in the evolution of many faunal groups and destroyed complete ecosystems but affected marine and terrestrial environments at slightly different times within a short time span of c. 100–300 kyr. The lower crisis interval in the uppermost Famennian started as a prelude with a minor eustatic sea-level fall, followed rather abruptly by pantropically widespread black shale deposition (Hangenberg Black Shale and equivalents). This transgressive and hypoxic/anoxic phase coincided with a global carbonate crisis and perturbation of the global carbon cycle as evidenced by a distinctive positive carbon isotope excursion, probably as a consequence of climate/salinity-driven oceanic overturns and outer-shelf eutrophication. It is the main extinction level for marine biota, especially for ammonoids, trilobites, conodonts, stromatoporoids, corals, some sharks, and deeper-water ostracodes, but probably also for placoderms, chitinozoans and early tetrapods. Extinction rates were lower for brachiopods, neritic ostracodes, bryozoans and echinoderms. Extinction patterns were similar in widely separate basins of the western and eastern Prototethys, while a contemporaneous marine macrofauna record from high latitudes is missing altogether. The middle crisis interval is characterized by a gradual but major eustatic sea-level fall, probably in the scale of more than 100 m, that caused the progradation of shallow-water siliciclastics (Hangenberg Sandstone and equivalents) and produced widespread unconformities due to reworking and non-deposition. The glacio-eustatic origin of this global regression is proven by miospore correlation with widespread diamictites of South America and South and North Africa, and by the evidence for significant tropical mountain glaciers in eastern North America. This isolated and short-lived plunge from global greenhouse into icehouse conditions may follow the significant drawdown of atmospheric CO 2 levels due to the prior massive burial of organic carbon during the global deposition of black shales. Increased carbon recycling by intensified terrestrial erosion in combination with the arrested burial of carbonates may have led to a gradual rise of CO 2 levels, re-warming, and a parallel increase in the influx of land-derived nutrients. The upper crisis interval in the uppermost Famennian is characterized by initial post-glacial transgression and a second global carbon isotope spike, as well as by opportunistic faunal blooms and the early re-radiation of several fossil groups. Minor reworking events and unconformities give evidence for continuing smaller-scale oscillations of sea-level and palaeoclimate. These may explain the terrestrial floral change near the Famennian–Tournaisian boundary and contemporaneous, evolutionarily highly significant extinctions of survivors of the main crisis. Still poorly understood small-scale events wiped out the last clymeniid ammonoids, phacopid trilobites, placoderms and some widespread brachiopod and foraminiferan groups. The post-crisis interval in the lower Tournaisian is marked by continuing eustatic rise (e.g. flooding of the Old Red Continent), and significant radiations in a renewed greenhouse time. But the recovery had not yet reached the pre-crisis level when it was suddenly interrupted by the global, second-order Lower Alum Shale Event at the base of the middle Tournaisian.

@article{doi101144sp4239,
    author = "Kaiser, Sandra I. and Aretz, Markus and Becker, Ralph Thomas",
    title = "The global Hangenberg Crisis (Devonian–Carboniferous transition): review of a first-order mass extinction",
    year = "2015",
    journal = "Geological Society London Special Publications",
    abstract = "Abstract The global Hangenberg Crisis near the Devonian–Carboniferous boundary (DCB) represents a mass extinction that is of the same scale as the so-called ‘Big Five’ first-order Phanerozoic events. It played an important role in the evolution of many faunal groups and destroyed complete ecosystems but affected marine and terrestrial environments at slightly different times within a short time span of c. 100–300 kyr. The lower crisis interval in the uppermost Famennian started as a prelude with a minor eustatic sea-level fall, followed rather abruptly by pantropically widespread black shale deposition (Hangenberg Black Shale and equivalents). This transgressive and hypoxic/anoxic phase coincided with a global carbonate crisis and perturbation of the global carbon cycle as evidenced by a distinctive positive carbon isotope excursion, probably as a consequence of climate/salinity-driven oceanic overturns and outer-shelf eutrophication. It is the main extinction level for marine biota, especially for ammonoids, trilobites, conodonts, stromatoporoids, corals, some sharks, and deeper-water ostracodes, but probably also for placoderms, chitinozoans and early tetrapods. Extinction rates were lower for brachiopods, neritic ostracodes, bryozoans and echinoderms. Extinction patterns were similar in widely separate basins of the western and eastern Prototethys, while a contemporaneous marine macrofauna record from high latitudes is missing altogether. The middle crisis interval is characterized by a gradual but major eustatic sea-level fall, probably in the scale of more than 100 m, that caused the progradation of shallow-water siliciclastics (Hangenberg Sandstone and equivalents) and produced widespread unconformities due to reworking and non-deposition. The glacio-eustatic origin of this global regression is proven by miospore correlation with widespread diamictites of South America and South and North Africa, and by the evidence for significant tropical mountain glaciers in eastern North America. This isolated and short-lived plunge from global greenhouse into icehouse conditions may follow the significant drawdown of atmospheric CO 2 levels due to the prior massive burial of organic carbon during the global deposition of black shales. Increased carbon recycling by intensified terrestrial erosion in combination with the arrested burial of carbonates may have led to a gradual rise of CO 2 levels, re-warming, and a parallel increase in the influx of land-derived nutrients. The upper crisis interval in the uppermost Famennian is characterized by initial post-glacial transgression and a second global carbon isotope spike, as well as by opportunistic faunal blooms and the early re-radiation of several fossil groups. Minor reworking events and unconformities give evidence for continuing smaller-scale oscillations of sea-level and palaeoclimate. These may explain the terrestrial floral change near the Famennian–Tournaisian boundary and contemporaneous, evolutionarily highly significant extinctions of survivors of the main crisis. Still poorly understood small-scale events wiped out the last clymeniid ammonoids, phacopid trilobites, placoderms and some widespread brachiopod and foraminiferan groups. The post-crisis interval in the lower Tournaisian is marked by continuing eustatic rise (e.g. flooding of the Old Red Continent), and significant radiations in a renewed greenhouse time. But the recovery had not yet reached the pre-crisis level when it was suddenly interrupted by the global, second-order Lower Alum Shale Event at the base of the middle Tournaisian.",
    url = "https://doi.org/10.1144/sp423.9",
    doi = "10.1144/sp423.9",
    openalex = "W2289667625",
    references = "doi101016jpalaeo200910010, doi101073pnas1117332109, doi1011302014250502"
}

ABSTRACT The number of Marcellus Shale gas wells drilled in the Appalachian basin has increased rapidly over the past decade, leading to increased interest in the highly saline water produced with the natural gas which must be recycled, treated, or injected into deep disposal wells. New geochemical and isotopic analyses of produced water for 3 time-series and 13 grab samples from Marcellus Shale gas wells in southwest and north central Pennsylvania (PA) are used to address the origin of the water and solutes produced over the long term (>12 months). The question of whether the produced water originated within the Marcellus Shale, or whether it may have been drawn from adjacent reservoirs via fractures is addressed using measurements of Ra228/Ra226 and Ra226 activity. These parameters indicate that the water originated in the Marcellus Shale, and can be more broadly used to trace water of Marcellus Shale origin. During the first 1–2 weeks of production, rapid increases in salinity and positive shifts in δ18O values were observed in the produced water, followed by more gradual changes until a compositional plateau was reached within approximately 1 yr. The δ18O values and relationships between Na, Cl, and Br provide evidence that the water produced after compositional stabilization is natural formation water, the salinity for which originated primarily from evaporatively concentrated paleoseawater. The rapid transition from injected water to chemically and isotopically distinct water while <50% of the injected water volume had been recovered, supports the hypothesis that significant volumes of injected water were removed from circulation by imbibition.

@article{doi10130607071413146,
    author = "Rowen, Elisabeth L. and Engle, Mark A. and Kraemer, Thomas F. and Schroeder, Karl T. and Hammack, Richard and Doughten, M.W.",
    title = "Geochemical and isotopic evolution of water produced from Middle Devonian Marcellus shale gas wells, Appalachian basin, Pennsylvania",
    year = "2015",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT The number of Marcellus Shale gas wells drilled in the Appalachian basin has increased rapidly over the past decade, leading to increased interest in the highly saline water produced with the natural gas which must be recycled, treated, or injected into deep disposal wells. New geochemical and isotopic analyses of produced water for 3 time-series and 13 grab samples from Marcellus Shale gas wells in southwest and north central Pennsylvania (PA) are used to address the origin of the water and solutes produced over the long term (\>12 months). The question of whether the produced water originated within the Marcellus Shale, or whether it may have been drawn from adjacent reservoirs via fractures is addressed using measurements of Ra228/Ra226 and Ra226 activity. These parameters indicate that the water originated in the Marcellus Shale, and can be more broadly used to trace water of Marcellus Shale origin. During the first 1–2 weeks of production, rapid increases in salinity and positive shifts in δ18O values were observed in the produced water, followed by more gradual changes until a compositional plateau was reached within approximately 1 yr. The δ18O values and relationships between Na, Cl, and Br provide evidence that the water produced after compositional stabilization is natural formation water, the salinity for which originated primarily from evaporatively concentrated paleoseawater. The rapid transition from injected water to chemically and isotopically distinct water while \<50\% of the injected water volume had been recovered, supports the hypothesis that significant volumes of injected water were removed from circulation by imbibition.",
    url = "https://doi.org/10.1306/07071413146",
    doi = "10.1306/07071413146",
    openalex = "W2106718980",
    references = "doi101016japgeochem201210002, doi101016s0016703701008845, doi101073pnas1121181109, doi101126science13334651702, doi101130001676061951621111ghosw20co2, doi101144gslsp19940780113, doi101306212f8cab2b2411d78648000102c1865d, doi102118131350ms, doi102118152596ms, doi1021187504ms"
}

@article{doi101016jpalaeo201604019,
    author = "Szrek, Piotr and Salwa, Sylwester and Niedźwiedzki, Grzegorz and Dec, Marek and Ahlberg, Per and Uchman, Alfred",
    title = "A glimpse of a fish face — An exceptional fish feeding trace fossil from the Lower Devonian of the Holy Cross Mountains, Poland",
    year = "2016",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2016.04.019",
    doi = "10.1016/j.palaeo.2016.04.019",
    openalex = "W2340063035",
    references = "doi101017s0022336000029279, doi101111j14754983200600594x, openalexw750766133"
}

@article{doi101016jpalaeo201608033,
    author = "Stössel, Iwan and Williams, Edward A. and Higgs, Kenneth T.",
    title = "Ichnology and depositional environment of the Middle Devonian Valentia Island tetrapod trackways, south-west Ireland",
    year = "2016",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2016.08.033",
    doi = "10.1016/j.palaeo.2016.08.033",
    openalex = "W2516785774",
    references = "doi101144001676492009022"
}

Ostracods from the Lower Devonian (Lochkovian) of the Argentine Precordillera Basin (upper levels of the Los Espejos Formation and lowermost ones of the Talacasto Formation) were studied. These units represent one of the best Lochkovian stratigraphic records in the Malvinokaffric basins. According to this revision, records of Devonian ostracod faunas in southwestern Gondwana can be extended to older stratigraphic levels. One new genus Suinella and ten species, including five new records (Suinella huarpesi gen. and sp. nov., Amphizona? argentinensis sp. nov., Bollia talacastensis sp. nov., Petrisigmoopsis? rotundum sp. nov. and Pircawayra antiqua sp. nov.) and one reassignment (Thilpsurella aff. T. putea Coryell and Cuskley) were hereby defined. The studied taxonomic assemblage differs from younger Devonian Malvinokaffric ostracod associations by being relatively diverse and composed mainly of drepanelloideans together with metacopids. The association is characterised by species with thin and spiny carapaces, a fact suggesting a relatively deep and low-energy environment below storm wave base. The mixed palaeobiogeographic affinities of the Lochkovian ostracod fauna contrasts with the clear Malvinokaffric signature of the upper Lower—Middle Devonian associations previously recognised in Argentina.

@article{doi105710amgh040720162967,
    author = "Salas, María José",
    title = "New Insights on Earliest Devonian (Lochkovian) Ostracods from the Argentine Precordillera",
    year = "2016",
    journal = "Ameghiniana",
    abstract = "Ostracods from the Lower Devonian (Lochkovian) of the Argentine Precordillera Basin (upper levels of the Los Espejos Formation and lowermost ones of the Talacasto Formation) were studied. These units represent one of the best Lochkovian stratigraphic records in the Malvinokaffric basins. According to this revision, records of Devonian ostracod faunas in southwestern Gondwana can be extended to older stratigraphic levels. One new genus Suinella and ten species, including five new records (Suinella huarpesi gen. and sp. nov., Amphizona? argentinensis sp. nov., Bollia talacastensis sp. nov., Petrisigmoopsis? rotundum sp. nov. and Pircawayra antiqua sp. nov.) and one reassignment (Thilpsurella aff. T. putea Coryell and Cuskley) were hereby defined. The studied taxonomic assemblage differs from younger Devonian Malvinokaffric ostracod associations by being relatively diverse and composed mainly of drepanelloideans together with metacopids. The association is characterised by species with thin and spiny carapaces, a fact suggesting a relatively deep and low-energy environment below storm wave base. The mixed palaeobiogeographic affinities of the Lochkovian ostracod fauna contrasts with the clear Malvinokaffric signature of the upper Lower—Middle Devonian associations previously recognised in Argentina.",
    url = "https://doi.org/10.5710/amgh.04.07.2016.2967",
    doi = "10.5710/amgh.04.07.2016.2967",
    openalex = "W2462578778",
    references = "openalexw2726120922"
}

Abstract The study of early actinopterygians (ray‐finned fishes) from the Devonian has been hampered by imperfect preservation in the majority of taxa. The Late Devonian (early Frasnian) Gogo Formation of north‐western Western Australia is notable in producing complete fossil actinopterygians with exceptional three‐dimensional preservation of both the dermal and endoskeletal anatomy. Four taxa have been described and have proved invaluable in understanding the anatomy of early representatives of this clade. Here, we present a fifth Gogo taxon, based on a single exceptionally preserved specimen and representing a new genus and species of early ray‐finned fish. The neurocranium was CT scanned, permitting a detailed examination of the endocast. The new taxon possesses unusual features including a greatly enlarged spiracular opening and extensive spinose ornamentation on the dermal skull bones, median ridge scutes and lepidotrichia. The endocast displays a mosaic of characters, some of which are similar to Mimipiscis and non‐actinopterygian outgroups, while other features are more akin to Raynerius from the Late Devonian of France as well as several stratigraphically younger taxa. A phylogenetic analysis resolves the new form as sister taxon to fishes from the Late Devonian of the northern hemisphere and all post‐Devonian actinopterygians, confirming that the assemblage of fossil ray fins from the Gogo Formation is part of the wider Devonian actinopterygian radiation.

@article{doi101002spp21243,
    author = "Choo, Brian and Lü, Jing and Giles, Sam and Trinajstic, Kate and Long, John A.",
    title = "A new actinopterygian from the Late Devonian Gogo Formation, Western Australia",
    year = "2018",
    journal = "Papers in Palaeontology",
    abstract = "Abstract The study of early actinopterygians (ray‐finned fishes) from the Devonian has been hampered by imperfect preservation in the majority of taxa. The Late Devonian (early Frasnian) Gogo Formation of north‐western Western Australia is notable in producing complete fossil actinopterygians with exceptional three‐dimensional preservation of both the dermal and endoskeletal anatomy. Four taxa have been described and have proved invaluable in understanding the anatomy of early representatives of this clade. Here, we present a fifth Gogo taxon, based on a single exceptionally preserved specimen and representing a new genus and species of early ray‐finned fish. The neurocranium was CT scanned, permitting a detailed examination of the endocast. The new taxon possesses unusual features including a greatly enlarged spiracular opening and extensive spinose ornamentation on the dermal skull bones, median ridge scutes and lepidotrichia. The endocast displays a mosaic of characters, some of which are similar to Mimipiscis and non‐actinopterygian outgroups, while other features are more akin to Raynerius from the Late Devonian of France as well as several stratigraphically younger taxa. A phylogenetic analysis resolves the new form as sister taxon to fishes from the Late Devonian of the northern hemisphere and all post‐Devonian actinopterygians, confirming that the assemblage of fossil ray fins from the Gogo Formation is part of the wider Devonian actinopterygian radiation.",
    url = "https://doi.org/10.1002/spp2.1243",
    doi = "10.1002/spp2.1243",
    openalex = "W2904845223",
    references = "doi101098rsos171727"
}

@article{doi101016jepsl201805016,
    author = "Huang, Cheng and Joachimski, Michael M. and Gong, Yiming",
    title = "Did climate changes trigger the Late Devonian Kellwasser Crisis? Evidence from a high-resolution conodont δ 18 O PO 4 record from South China",
    year = "2018",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/j.epsl.2018.05.016",
    doi = "10.1016/j.epsl.2018.05.016",
    openalex = "W2804398341",
    references = "doi101144001676492009022"
}

@article{doi101016jsedgeo201811001,
    author = "Guo, Xuelian and Retallack, Gregory J. and Lü, Bin and He, Lusheng and Wang, Rong-Hua and Song, Hong",
    title = "Paleosols in Devonian red-beds from northwest China and their paleoclimatic characteristics",
    year = "2018",
    journal = "Sedimentary Geology",
    url = "https://doi.org/10.1016/j.sedgeo.2018.11.001",
    doi = "10.1016/j.sedgeo.2018.11.001",
    openalex = "W2900209604",
    references = "doi101144001676492009022"
}

The majority of the analyses of the evolutionary history of the megadiverse class Insecta are based on the documented taxonomic palaeobiodiversity. A different approach, poorly investigated, is to focus on morphological disparity, linked to changes in the organisms' functioning. Here we establish a hierarchy of the great geological epochs based on a new method using Wagner parsimony and a 'presence/absence of a morphological type of mouthpart of Hexapoda' dataset. We showed the absence of major rupture in the evolution of the mouthparts, but six epochs during which numerous innovations and few extinctions happened, i.e., Late Carboniferous, Middle and Late Triassic, 'Callovian-Oxfordian', 'Early' Cretaceous, and 'Albian-Cenomanian'. The three crises Permian-Triassic, Triassic-Jurassic, and Cretaceous-Cenozoic had no strong, visible impact on mouthparts types. We particularly emphasize the origination of mouthparts linked to nectarivory during the Cretaceous Terrestrial Revolution. We also underline the origination of mouthparts linked to phytophagy during the Middle and the Late Triassic, correlated to the diversification of the gymnosperms, especially in relation to the complex 'flowers' producing nectar of the Bennettitales and Gnetales.

@article{doi101038s41598018219381,
    author = "Nel, Patricia and Bertrand, Sylvain and Nel, André",
    title = "Diversification of insects since the Devonian: a new approach based on morphological disparity of mouthparts",
    year = "2018",
    journal = "Scientific Reports",
    abstract = "The majority of the analyses of the evolutionary history of the megadiverse class Insecta are based on the documented taxonomic palaeobiodiversity. A different approach, poorly investigated, is to focus on morphological disparity, linked to changes in the organisms' functioning. Here we establish a hierarchy of the great geological epochs based on a new method using Wagner parsimony and a 'presence/absence of a morphological type of mouthpart of Hexapoda' dataset. We showed the absence of major rupture in the evolution of the mouthparts, but six epochs during which numerous innovations and few extinctions happened, i.e., Late Carboniferous, Middle and Late Triassic, 'Callovian-Oxfordian', 'Early' Cretaceous, and 'Albian-Cenomanian'. The three crises Permian-Triassic, Triassic-Jurassic, and Cretaceous-Cenozoic had no strong, visible impact on mouthparts types. We particularly emphasize the origination of mouthparts linked to nectarivory during the Cretaceous Terrestrial Revolution. We also underline the origination of mouthparts linked to phytophagy during the Middle and the Late Triassic, correlated to the diversification of the gymnosperms, especially in relation to the complex 'flowers' producing nectar of the Bennettitales and Gnetales.",
    url = "https://doi.org/10.1038/s41598-018-21938-1",
    doi = "10.1038/s41598-018-21938-1",
    openalex = "W2790566485",
    references = "doi101073pnas1117332109"
}

ABSTRACT Thomson (1968 Thomson, K. S. 1968. A new Devonian fish (Crossopterygii: Rhipidistia) considered in relation to the origin of the Amphibia. Postilla 124:1–13. [Google Scholar], Postilla 124:1–13) described and diagnosed the tristichopterid Hyneria lindae from parts of a disarticulated skull and isolated scales recovered from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A. Since the publication of that description, knowledge of the tristichopterid clade has grown significantly, with numerous new descriptions of Famennian taxa from around the world. Additionally, a concerted effort to collect vertebrates from the Catskill Formation in Pennsylvania has produced significant new material of Hyneria lindae from the type locality at Red Hill, Clinton County, Pennsylvania. The new material serves as the basis for a rediagnosis and redescription of Hyneria lindae. The species is uniquely diagnosed by features including scales with a fringed free margin, a wide and blunt snout, and short intertemporals. The redescription of H. lindae gives occasion to review all of the Catskill Formation tristichopterid material that requires further diagnosis. This includes a near-complete cranial specimen collected near Red Hill that was originally diagnosed as Eusthenodon wängsjöi by Thomson (1976 Thomson, K. S. 1976. The faunal relationships of rhipidistian fishes (Crossopterygii) from the Catskill (Upper Devonian) of Pennsylvania. Journal of Paleontology 50:1203–1208.[Web of Science ®], [Google Scholar]; Journal of Paleontology 50:1203–1208) and is here revised as Hyneria cf. lindae and figured for the first time. The emerging sample of tristichopterids from the Catskill Formation informs the diversity and paleobiogeography of these large predators in the fluvial ecosystems of the Red Hill site and within the Catskill Delta complex. Citation for this article: Daeschler, E. B., and J. P. Downs. 2018. New description and diagnosis of Hyneria lindae (Sarcopterygii, Tristichopteridae) from the Upper Devonian Catskill Formation in Pennsylvania, U.S.A. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1448834.

@article{doi1010800272463420181448834,
    author = "Daeschler, Edward B. and Downs, Jason P.",
    title = "New description and diagnosis of Hyneria lindae (Sarcopterygii, Tristichopteridae) from the Upper Devonian Catskill Formation in Pennsylvania, U.S.A.",
    year = "2018",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Thomson (1968 Thomson, K. S. 1968. A new Devonian fish (Crossopterygii: Rhipidistia) considered in relation to the origin of the Amphibia. Postilla 124:1–13. [Google Scholar], Postilla 124:1–13) described and diagnosed the tristichopterid Hyneria lindae from parts of a disarticulated skull and isolated scales recovered from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A. Since the publication of that description, knowledge of the tristichopterid clade has grown significantly, with numerous new descriptions of Famennian taxa from around the world. Additionally, a concerted effort to collect vertebrates from the Catskill Formation in Pennsylvania has produced significant new material of Hyneria lindae from the type locality at Red Hill, Clinton County, Pennsylvania. The new material serves as the basis for a rediagnosis and redescription of Hyneria lindae. The species is uniquely diagnosed by features including scales with a fringed free margin, a wide and blunt snout, and short intertemporals. The redescription of H. lindae gives occasion to review all of the Catskill Formation tristichopterid material that requires further diagnosis. This includes a near-complete cranial specimen collected near Red Hill that was originally diagnosed as Eusthenodon wängsjöi by Thomson (1976 Thomson, K. S. 1976. The faunal relationships of rhipidistian fishes (Crossopterygii) from the Catskill (Upper Devonian) of Pennsylvania. Journal of Paleontology 50:1203–1208.[Web of Science ®], [Google Scholar]; Journal of Paleontology 50:1203–1208) and is here revised as Hyneria cf. lindae and figured for the first time. The emerging sample of tristichopterids from the Catskill Formation informs the diversity and paleobiogeography of these large predators in the fluvial ecosystems of the Red Hill site and within the Catskill Delta complex. Citation for this article: Daeschler, E. B., and J. P. Downs. 2018. New description and diagnosis of Hyneria lindae (Sarcopterygii, Tristichopteridae) from the Upper Devonian Catskill Formation in Pennsylvania, U.S.A. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1448834.",
    url = "https://doi.org/10.1080/02724634.2018.1448834",
    doi = "10.1080/02724634.2018.1448834",
    openalex = "W2801303374",
    references = "doi101144sp33910"
}

@article{doi101016jcub201911067,
    author = "Stein, William E. and Berry, Christopher M. and Morris, Jennifer L. and Hernick, Linda VanAller and Mannolini, Frank and Straeten, Charles Ver and Landing, Ed and Marshall, John and Wellman, Charles H. and Beerling, David J. and Leake, Jonathan R.",
    title = "Mid-Devonian Archaeopteris Roots Signal Revolutionary Change in Earliest Fossil Forests",
    year = "2019",
    journal = "Current Biology",
    url = "https://doi.org/10.1016/j.cub.2019.11.067",
    doi = "10.1016/j.cub.2019.11.067",
    openalex = "W2994812694",
    references = "bridge1994marine, doi101016jpalaeo201010040, doi101144sp3396, doi1023073515409"
}

@article{doi101016jpalaeo201902025,
    author = "Wan, Zhenzhu and Algeo, Thomas J. and Gensel, Patricia G. and Scheckler, Stephen E. and Stein, William E. and Cressler, Walter and Berry, Christopher M. and Xu, Hong‐He and Rowe, Harry and Sauer, Peter E.",
    title = "Environmental influences on the stable carbon isotopic composition of Devonian and Early Carboniferous land plants",
    year = "2019",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2019.02.025",
    doi = "10.1016/j.palaeo.2019.02.025",
    openalex = "W2921670913",
    references = "doi101144sp33910"
}

@article{doi101007s1254902000446z,
    author = "Nazik, Atike and Königshof, Peter and Ariuntogos, M. and Waters, Johnny A. and Carmichael, Sarah K.",
    title = "Late Devonian ostracods (Crustacea) from the Hushoot Shiveetiin gol section (Baruunhuurai Terrane, Mongolia) and their palaeoenvironmental implication and palaeobiogeographic relationship",
    year = "2020",
    journal = "Palaeobiodiversity and Palaeoenvironments",
    url = "https://doi.org/10.1007/s12549-020-00446-z",
    doi = "10.1007/s12549-020-00446-z",
    openalex = "W3094158875",
    references = "openalexw2726120922"
}

@incollection{doi101016b978012824360200022x,
    author = "Becker, Ralph Thomas and Marshall, John and Silva, Anne‐Christine Da and Agterberg, Frits and Gradstein, Felix M. and Ogg, James G.",
    title = "The Devonian Period",
    year = "2020",
    booktitle = "Elsevier eBooks",
    url = "https://doi.org/10.1016/b978-0-12-824360-2.00022-x",
    doi = "10.1016/b978-0-12-824360-2.00022-x",
    openalex = "W4211189811",
    references = "doi1010079781402068065, doi1010079783642796340, doi101016b9780128243602000231, doi101016jepsl200905028, doi101016s0009254102003972, doi101016s0016703703004228, doi101016s003101820100476x, doi101016s0031018204004663, doi101038nature10819, doi1010510004636120041335, doi10105100046361201116836, doi101126science1161648, doi10113000167606198596567defie20co2, doi1011300091761319808281przfld20co2, doi102110jsr2010093, doi1023071485834, doi105252g2017n3a5, doi105860choice402180, lenz2013early, openalexw1252084533"
}

The Waterloo Farm lagerstätte in South Africa provides a uniquely well-preserved record of a Latest Devonian estuarine ecosystem. Ecological evidence from it is reviewed, contextualised, and compared with that available from the analogous Swartvlei estuarine lake, with a particular emphasis on their piscean inhabitants. Although the taxonomic affinities of the estuarine species are temporally very different, the overall patterns of utilisation prove to be remarkably congruent, with similar trophic structures. Significantly, both systems show evidence of widespread use of estuaries as fish nurseries by both resident and marine migrant taxa. Holocene estuaries are almost exclusively utilised by actinopterygians which are overwhelmingly dominated by oviparous species. Complex strategies are utilised by estuarine resident species to avoid exposure of eggs to environmental stresses that characterize these systems. By contrast, many of the groups utilising Devonian estuaries were likely live bearers, potentially allowing them to avoid the challenges faced by oviparous taxa. This may have contributed to dominance of these systems by non-actinoptergians prior to the End Devonian Mass Extinction. The association of early aquatic tetrapods at Waterloo Farm with a fish nursery environment is consistent with findings from North America, Belgium and Russia, and may be implied by the estuarine settings of a number of other Devonian tetrapods. Tetrapods apparently replace their sister group, the elpistostegids, in estuaries with both groups having been postulated to be adaptated to shallow water habitats where they could access small piscean prey. Correlation of tetrapods (and elpistostegids) with fish nursery areas in the Late Devonian lends strong support to this hypothesis, suggesting that adaptations permitting improved access to the abundant juvenile fish within the littoral zone of estuarine lakes and continental water bodies may have been pivotal in the evolution of tetrapods.

@article{doi101111brv12590,
    author = "Gess, Robert W. and Whitfield, Alan K.",
    title = "Estuarine fish and tetrapod evolution: insights from a Late Devonian (Famennian) Gondwanan estuarine lake and a southern African Holocene equivalent",
    year = "2020",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "The Waterloo Farm lagerstätte in South Africa provides a uniquely well-preserved record of a Latest Devonian estuarine ecosystem. Ecological evidence from it is reviewed, contextualised, and compared with that available from the analogous Swartvlei estuarine lake, with a particular emphasis on their piscean inhabitants. Although the taxonomic affinities of the estuarine species are temporally very different, the overall patterns of utilisation prove to be remarkably congruent, with similar trophic structures. Significantly, both systems show evidence of widespread use of estuaries as fish nurseries by both resident and marine migrant taxa. Holocene estuaries are almost exclusively utilised by actinopterygians which are overwhelmingly dominated by oviparous species. Complex strategies are utilised by estuarine resident species to avoid exposure of eggs to environmental stresses that characterize these systems. By contrast, many of the groups utilising Devonian estuaries were likely live bearers, potentially allowing them to avoid the challenges faced by oviparous taxa. This may have contributed to dominance of these systems by non-actinoptergians prior to the End Devonian Mass Extinction. The association of early aquatic tetrapods at Waterloo Farm with a fish nursery environment is consistent with findings from North America, Belgium and Russia, and may be implied by the estuarine settings of a number of other Devonian tetrapods. Tetrapods apparently replace their sister group, the elpistostegids, in estuaries with both groups having been postulated to be adaptated to shallow water habitats where they could access small piscean prey. Correlation of tetrapods (and elpistostegids) with fish nursery areas in the Late Devonian lends strong support to this hypothesis, suggesting that adaptations permitting improved access to the abundant juvenile fish within the littoral zone of estuarine lakes and continental water bodies may have been pivotal in the evolution of tetrapods.",
    url = "https://doi.org/10.1111/brv.12590",
    doi = "10.1111/brv.12590",
    openalex = "W3006644454",
    references = "doi101017s1755691018000695"
}

A brief UV-B burst, during a climatic warming interval, collapsed the Devonian-Carboniferous boundary terrestrial ecosystem.

@article{doi101126sciadvaba0768,
    author = "Marshall, John and Lakin, Jon and Troth, Ian and Wallace-Johnson, Sarah M.",
    title = "UV-B radiation was the Devonian-Carboniferous boundary terrestrial extinction kill mechanism",
    year = "2020",
    journal = "Science Advances",
    abstract = "A brief UV-B burst, during a climatic warming interval, collapsed the Devonian-Carboniferous boundary terrestrial ecosystem.",
    url = "https://doi.org/10.1126/sciadv.aba0768",
    doi = "10.1126/sciadv.aba0768",
    openalex = "W3031950949",
    references = "doi101073pnas1117332109, doi10247508201801"
}

The Devonian has long been a problematic period for paleomagnetism. Devonian paleomagnetic data are generally difficult to interpret and have complex partial or full overprints– problems that arise in data obtained from both sedimentary and igneous rocks. As a result, the reconstruction of tectonic plate motions, largely performed using apparent polar wander paths, has large uncertainty. Similarly, the Devonian geomagnetic polarity time scale is very poorly constrained. Paleointensity studies from volcanic units suggest that the field was much weaker than the modern field, and it has been hypothesised that this was accompanied by many polarity reversals (a hyperreversing field). We sampled Middle to Upper Devonian sections in Germany, Poland and Canada which show low conodont alteration indices, implying low thermal maturity. We show that there are significant issues with these data, which are not straightforward to interpret, even though no significant heating or remineralisation appears to have caused overprinting. We compare our data to other magnetostratigraphic studies from the Devonian and review the polarity pattern as presented in the Geologic Time Scale. Combined with estimates for the strength of the magnetic field, we suggest that the field during the Devonian might have been so weak, and in part non-dipolar, that obtaining reliable primary paleomagnetic data from Devonian rocks is challenging. Careful examination of all data, no matter how unusual, is the best way to push forward our understanding of the Devonian magnetic field. Paleointensity studies show that the field during the Devonian had a similar low strength to the Ediacaran. Independent evidence from malformed spores around the Devonian-Carboniferous boundary suggests that the terrestrial extinction connected to the Hangenberg event was caused by increased UV-B radiation, supporting the weak field hypothesis. A fundamentally weak and possibly non-dipolar field during the Devonian could have been produced, in part, by true polar wander acting to maximise core-mantle heat flow in the equatorial region. It may also have influenced evolution and extinctions in this time period. There are a large number of paleobiological crises in the Devonian, and we pose the question, did the Earth’s magnetic field influence these crises?

@article{doi101016jearscirev2022104073,
    author = "van der Boon, Annique and Biggin, Andrew and Thallner, Daniele and Hounslow, Mark W. and Bono, Richard K. and Nawrocki, Jerzy and Wójcik, Krystian and Paszkowski, Mariusz and Königshof, Peter and Backer, Tim De and Kabanov, Pavel and Gouwy, Sofie and Vandenberg, Richard and Silva, Anne‐Christine Da",
    title = "A persistent non-uniformitarian paleomagnetic field in the Devonian?",
    year = "2022",
    journal = "Earth-Science Reviews",
    abstract = "The Devonian has long been a problematic period for paleomagnetism. Devonian paleomagnetic data are generally difficult to interpret and have complex partial or full overprints– problems that arise in data obtained from both sedimentary and igneous rocks. As a result, the reconstruction of tectonic plate motions, largely performed using apparent polar wander paths, has large uncertainty. Similarly, the Devonian geomagnetic polarity time scale is very poorly constrained. Paleointensity studies from volcanic units suggest that the field was much weaker than the modern field, and it has been hypothesised that this was accompanied by many polarity reversals (a hyperreversing field). We sampled Middle to Upper Devonian sections in Germany, Poland and Canada which show low conodont alteration indices, implying low thermal maturity. We show that there are significant issues with these data, which are not straightforward to interpret, even though no significant heating or remineralisation appears to have caused overprinting. We compare our data to other magnetostratigraphic studies from the Devonian and review the polarity pattern as presented in the Geologic Time Scale. Combined with estimates for the strength of the magnetic field, we suggest that the field during the Devonian might have been so weak, and in part non-dipolar, that obtaining reliable primary paleomagnetic data from Devonian rocks is challenging. Careful examination of all data, no matter how unusual, is the best way to push forward our understanding of the Devonian magnetic field. Paleointensity studies show that the field during the Devonian had a similar low strength to the Ediacaran. Independent evidence from malformed spores around the Devonian-Carboniferous boundary suggests that the terrestrial extinction connected to the Hangenberg event was caused by increased UV-B radiation, supporting the weak field hypothesis. A fundamentally weak and possibly non-dipolar field during the Devonian could have been produced, in part, by true polar wander acting to maximise core-mantle heat flow in the equatorial region. It may also have influenced evolution and extinctions in this time period. There are a large number of paleobiological crises in the Devonian, and we pose the question, did the Earth’s magnetic field influence these crises?",
    url = "https://doi.org/10.1016/j.earscirev.2022.104073",
    doi = "10.1016/j.earscirev.2022.104073",
    openalex = "W4281676666",
    references = "doi101144sp37115"
}

@article{doi101016jearscirev2022104290,
    author = "Xue, Jinzhuang and Wang, Jiashu and Huang, Pu and Liu, Lu and Huang, Tianzheng and Zhang, Lijun and Wang, Xianyan and Shen, Bing and Wang, Deming and Liu, Jianbo and Davies, Neil S. and Basinger, James F.",
    title = "The colonization of drylands by early vascular plants: Evidence from Early Devonian fossil soils and in situ plant traces from South China",
    year = "2022",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/j.earscirev.2022.104290",
    doi = "10.1016/j.earscirev.2022.104290",
    openalex = "W4313399708",
    references = "doi101016jearscirev201803004, doi101016jearscirev2022104085, doi101144001676492009022, doi101144jgs2015022"
}

@article{doi101016jgloplacha2022103874,
    author = "Ma, Kunyuan and Hinnov, Linda A. and Zhang, Xinsong and Gong, Yiming",
    title = "Astronomical climate changes trigger Late Devonian bio- and environmental events in South China",
    year = "2022",
    journal = "Global and Planetary Change",
    url = "https://doi.org/10.1016/j.gloplacha.2022.103874",
    doi = "10.1016/j.gloplacha.2022.103874",
    openalex = "W4283260032",
    references = "doi101144001676492009022"
}

@article{doi101038s41559022019194,
    author = "Giles, Sam and Feilich, Kara and Warnock, Rachel C. M. and Pierce, Stephanie E. and Friedman, Matt",
    title = "A Late Devonian actinopterygian suggests high lineage survivorship across the end-Devonian mass extinction",
    year = "2022",
    journal = "Nature Ecology \& Evolution",
    url = "https://doi.org/10.1038/s41559-022-01919-4",
    doi = "10.1038/s41559-022-01919-4",
    openalex = "W4309219026",
    references = "doi101016b978012824360200022x, doi101073pnas0914000107, doi101073pnas1319091111, doi101080106351599260472, doi101086284325, doi101093sysbiosys029, doi101098rsos171727, doi1011112041210x12066, doi101111j10960031200800217x, doi101111j14636395200800361x, doi101111j2041210x201100169x, doi101126science1229237, doi101371journalpbio3000494"
}

The Eifelian-aged Hangman Sandstone Formation of southwest England is a unit of the ‘Old Red Sandstone’ that has traditionally been considered relatively barren of trace fossils. Following recent investigations, we here show it to contain the most diverse Middle Devonian non-marine ichnofauna known globally. The fluvial-lacustrine facies of its constituent Trentishoe Member contain representatives of 21 ichnogenera including Archaeonassa, Arenicolites, Beaconites, Bifungites, Circulichnis, Cruziana, Diplichnites,?Gluckstadella, Gordia,?Halimededes,?Lockeia, Merostomichnites, Palmichnium, Petalichnus, Planolites, Polarichnus, Rusophycus, Siskemia, Spirophyton, Steinsfjordichnus, and Taenidium, as well as several microbially induced sedimentary structures. The transitional marine-influenced facies of the underlying Hollowbrook Member are less extensively exposed but contain four additional unique ichnogenera in the form of Cochlichnus, Halopoa, Phycodes, and Teichichnus, as well as further examples of Cruziana, Planolites and Taenidium. A revised ichnological assessment of the unit reveals several notable features, including the youngest known example of the arthropod refugia trace, Polarichnus, as well as a transitional trace fossil form of Diplichnites-Beaconites, demonstrating that the latter was produced by arthropods. As the Hangman Sandstone Formation records the culmination of a marine regression, its ichnofauna can be compared with that of the conformably underlying Lynton Formation, which was deposited in a sandy marine shelf setting. The ichnological differences between these units are acute, with 88% of the Hangman Sandstone Formation trace fossils being exclusive to non-marine or transitional facies. This observation sheds light on the terrestrialization process and indicates that the segregation of marine and non-marine trace fossil communities had accelerated by the Middle Devonian. Internal variability in ichnological signatures within the Hangman Sandstone Formation is also pronounced, with greater ichnodiversity and ichnodisparity in distal fluvio-lacustrine facies than in proximal fluvial facies. By viewing the depositional environment of the unit as a regionally extensive distributive fluvial system, this variability can be partly explained by a bias arising from the distribution of true substrates (bedding planes that demonstrably preserve an ancient sediment-air interface) in the unit, with such phenomena being more readily preserved in the lower energy outer reaches of the depositional system.

@article{doi101016jpalaeo2023111671,
    author = "Davies, Neil S. and McMahon, William J. and Shillito, Anthony P. and Veenma, Yorick P. and Craig, James A.",
    title = "Ichnology of a Middle Devonian regression: Environment, terrestrialization and true substrate controls on trace fossils of the Hangman Sandstone Formation, SW England",
    year = "2023",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    abstract = "The Eifelian-aged Hangman Sandstone Formation of southwest England is a unit of the ‘Old Red Sandstone’ that has traditionally been considered relatively barren of trace fossils. Following recent investigations, we here show it to contain the most diverse Middle Devonian non-marine ichnofauna known globally. The fluvial-lacustrine facies of its constituent Trentishoe Member contain representatives of 21 ichnogenera including Archaeonassa, Arenicolites, Beaconites, Bifungites, Circulichnis, Cruziana, Diplichnites,?Gluckstadella, Gordia,?Halimededes,?Lockeia, Merostomichnites, Palmichnium, Petalichnus, Planolites, Polarichnus, Rusophycus, Siskemia, Spirophyton, Steinsfjordichnus, and Taenidium, as well as several microbially induced sedimentary structures. The transitional marine-influenced facies of the underlying Hollowbrook Member are less extensively exposed but contain four additional unique ichnogenera in the form of Cochlichnus, Halopoa, Phycodes, and Teichichnus, as well as further examples of Cruziana, Planolites and Taenidium. A revised ichnological assessment of the unit reveals several notable features, including the youngest known example of the arthropod refugia trace, Polarichnus, as well as a transitional trace fossil form of Diplichnites-Beaconites, demonstrating that the latter was produced by arthropods. As the Hangman Sandstone Formation records the culmination of a marine regression, its ichnofauna can be compared with that of the conformably underlying Lynton Formation, which was deposited in a sandy marine shelf setting. The ichnological differences between these units are acute, with 88\% of the Hangman Sandstone Formation trace fossils being exclusive to non-marine or transitional facies. This observation sheds light on the terrestrialization process and indicates that the segregation of marine and non-marine trace fossil communities had accelerated by the Middle Devonian. Internal variability in ichnological signatures within the Hangman Sandstone Formation is also pronounced, with greater ichnodiversity and ichnodisparity in distal fluvio-lacustrine facies than in proximal fluvial facies. By viewing the depositional environment of the unit as a regionally extensive distributive fluvial system, this variability can be partly explained by a bias arising from the distribution of true substrates (bedding planes that demonstrably preserve an ancient sediment-air interface) in the unit, with such phenomena being more readily preserved in the lower energy outer reaches of the depositional system.",
    url = "https://doi.org/10.1016/j.palaeo.2023.111671",
    doi = "10.1016/j.palaeo.2023.111671",
    openalex = "W4379740348",
    references = "doi101016jearscirev2022104085, doi101016s0016787887800433, doi101111j14754983200600594x"
}

The vertebrate water-to-land transition and the rise of tetrapods brought about fundamental changes for the groups undergoing these evolutionary changes (i.e. stem and early tetrapods). These groups were forced to adapt to new conditions, including the distinct physical properties of water and air, requiring fundamental changes in anatomy. Nutrition (or feeding) was one of the prime physiological processes these vertebrates had to successfully adjust to change from aquatic to terrestrial life. The basal gnathostome feeding mode involves either jaw prehension or using water flows to aid in ingestion, transportation and food orientation. Meanwhile, processing was limited primarily to simple chewing bites. However, given their comparatively massive and relatively inflexible hyobranchial system (compared to the more muscular tongue of many tetrapods), it remains fraught with speculation how stem and early tetrapods managed to feed in both media. Here, we explore ontogenetic water-to-land transitions of salamanders as functional analogues to model potential changes in the feeding behaviour of stem and early tetrapods. Our data suggest two scenarios for terrestrial feeding in stem and early tetrapods as well as the presence of complex chewing behaviours, including excursions of the jaw in more than one dimension during early developmental stages. Our results demonstrate that terrestrial feeding may have been possible before flexible tongues evolved. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.

@article{doi101098rstb20220541,
    author = "Schwarz, Daniel and Heiss, Egon and Pierson, Todd W. and Konow, Nicolai and Schoch, Rainer R.",
    title = "Using salamanders as model taxa to understand vertebrate feeding constraints during the late Devonian water-to-land transition",
    year = "2023",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "The vertebrate water-to-land transition and the rise of tetrapods brought about fundamental changes for the groups undergoing these evolutionary changes (i.e. stem and early tetrapods). These groups were forced to adapt to new conditions, including the distinct physical properties of water and air, requiring fundamental changes in anatomy. Nutrition (or feeding) was one of the prime physiological processes these vertebrates had to successfully adjust to change from aquatic to terrestrial life. The basal gnathostome feeding mode involves either jaw prehension or using water flows to aid in ingestion, transportation and food orientation. Meanwhile, processing was limited primarily to simple chewing bites. However, given their comparatively massive and relatively inflexible hyobranchial system (compared to the more muscular tongue of many tetrapods), it remains fraught with speculation how stem and early tetrapods managed to feed in both media. Here, we explore ontogenetic water-to-land transitions of salamanders as functional analogues to model potential changes in the feeding behaviour of stem and early tetrapods. Our data suggest two scenarios for terrestrial feeding in stem and early tetrapods as well as the presence of complex chewing behaviours, including excursions of the jaw in more than one dimension during early developmental stages. Our results demonstrate that terrestrial feeding may have been possible before flexible tongues evolved. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.",
    url = "https://doi.org/10.1098/rstb.2022.0541",
    doi = "10.1098/rstb.2022.0541",
    openalex = "W4387651962",
    references = "doi101007s1205200901192"
}

The evolution of trees and forests through the Devonian Period fundamentally changed the Earth's land biosphere, as well as impacting physical environments and geomorphology by stabilizing sediments and interacting with flowing air and water. From the mid-Givetian Age onwards, lignophyte flora are known to have been key parts of the machinery in the so-called Devonian landscape factory, but the impact of earlier forests, dominated by less woody cladoxylopsids, are not as well understood. We report here evidence for a previously unrecognized cladoxylopsid forest landscape, archived within the Eifelian Hangman Sandstone Formation of Somerset and Devon, SW England. This unit has previously been considered palaeobotanically depauperate, but is here shown to contain the earliest fossil evidence for such trees in the British record, as well as the oldest known evidence globally for the relative position of standing trees: in common parlance, a fossil forest. In addition to abundant fossil material attributable to the cladoxylopsid tree Calamophyton, and other early Mid-Devonian flora, the sedimentary context of the plant remains sheds light on the biogeomorphic impacts of these earliest forests. The trees colonized a sizeable distributive fluvial system that was prone to seasonal disturbance events. The nature of the sedimentary system has created a bias to those facies where biogeomorphic signatures are most frequently recorded (from the distal parts of the system), but across the whole system there is evidence of plant–sediment interactions in the form of vegetation-induced sedimentary structures, rooting features and accumulations of plant debris. Plant remains are also found in nearshore facies adjacent to the distributive fluvial system, attesting to the development of a novel non-marine/marine teleconnection from the production and export of new biological sedimentary particles. The Hangman Sandstone Formation is illustrative of the revolutionary power of cladoxylopsid trees as biogeomorphic agents, forming densely spaced forests and shedding exceptionally abundant plant debris, while also impacting local landforms and sediment accumulations and profoundly changing landform resilience against flood disturbance events. These findings provide evidence that the Eifelian Stage (393.3–387.7 Ma) marks the onset of tree-driven changes to physical environments that would forever change Earth's non-marine landscapes and biosphere. Supplementary material: Details of sedimentary facies and additional images of plant fossils are available at https://doi.org/10.6084/m9.figshare.c.7084873

@article{doi101144jgs2023204,
    author = "Davies, Neil S. and McMahon, William J. and Berry, Christopher M.",
    title = "Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England",
    year = "2024",
    journal = "Journal of the Geological Society",
    abstract = "The evolution of trees and forests through the Devonian Period fundamentally changed the Earth's land biosphere, as well as impacting physical environments and geomorphology by stabilizing sediments and interacting with flowing air and water. From the mid-Givetian Age onwards, lignophyte flora are known to have been key parts of the machinery in the so-called Devonian landscape factory, but the impact of earlier forests, dominated by less woody cladoxylopsids, are not as well understood. We report here evidence for a previously unrecognized cladoxylopsid forest landscape, archived within the Eifelian Hangman Sandstone Formation of Somerset and Devon, SW England. This unit has previously been considered palaeobotanically depauperate, but is here shown to contain the earliest fossil evidence for such trees in the British record, as well as the oldest known evidence globally for the relative position of standing trees: in common parlance, a fossil forest. In addition to abundant fossil material attributable to the cladoxylopsid tree Calamophyton, and other early Mid-Devonian flora, the sedimentary context of the plant remains sheds light on the biogeomorphic impacts of these earliest forests. The trees colonized a sizeable distributive fluvial system that was prone to seasonal disturbance events. The nature of the sedimentary system has created a bias to those facies where biogeomorphic signatures are most frequently recorded (from the distal parts of the system), but across the whole system there is evidence of plant–sediment interactions in the form of vegetation-induced sedimentary structures, rooting features and accumulations of plant debris. Plant remains are also found in nearshore facies adjacent to the distributive fluvial system, attesting to the development of a novel non-marine/marine teleconnection from the production and export of new biological sedimentary particles. The Hangman Sandstone Formation is illustrative of the revolutionary power of cladoxylopsid trees as biogeomorphic agents, forming densely spaced forests and shedding exceptionally abundant plant debris, while also impacting local landforms and sediment accumulations and profoundly changing landform resilience against flood disturbance events. These findings provide evidence that the Eifelian Stage (393.3–387.7 Ma) marks the onset of tree-driven changes to physical environments that would forever change Earth's non-marine landscapes and biosphere. Supplementary material: Details of sedimentary facies and additional images of plant fossils are available at https://doi.org/10.6084/m9.figshare.c.7084873",
    url = "https://doi.org/10.1144/jgs2023-204",
    doi = "10.1144/jgs2023-204",
    openalex = "W4392104690",
    references = "doi101016jearscirev2022104085, doi101017s1755691018000695"
}

Central New South Wales, Australia, has a rich fossil record of Late Devonian (Famennian) fossil fish (eight species, mostly Bothriolepis and Remigolepis) and a single tetrapod (Metaxygnathus). This paper presents, for the first time, evidence from trace fossils, fossil plants, and palaeosols of the Hervey Group for the palaeoenvironment and evolution of Devonian tetrapods and fish. Late Devonian palaeosols of the Hervey Group in New South Wales formed in a semiarid climate with low shrubby desert vegetation, but at two levels including one with a tetrapod, there is evidence of subhumid woodland. That double spike to subhumid climate matches palaeoclimatic spikes in Pennsylvania cued to global atmospheric spikes in carbon dioxide correlated with the Annulata event of marine black shales dated at 365 Ma. This evidence supports the woodland hypothesis of tetrapod origins rather than the idea that they evolved from fish escaping shrinking desert ponds, or evolved in tidal flats. The Canowindra fish bed of mass mortality in a desiccated billabong (oxbow lake) is a stunning example of what happened in drying desert ponds. New South Wales has no clear evidence of intertidal vertebrates, and trackways which inspired this hypothesis are now controversial. In otherwise aquatic Late Devonian tetrapods, limbs may have been adaptations to negotiating or hiding from predators in streams choked with woody debris, and their necks allowed feeding on land, or in water shallower than their bodies.

@article{doi1018261let5715,
    author = "Retallack, Gregory J.",
    title = "Late Devonian fossils of New South Wales and early tetrapod habitats",
    year = "2024",
    journal = "Lethaia",
    abstract = "Central New South Wales, Australia, has a rich fossil record of Late Devonian (Famennian) fossil fish (eight species, mostly Bothriolepis and Remigolepis) and a single tetrapod (Metaxygnathus). This paper presents, for the first time, evidence from trace fossils, fossil plants, and palaeosols of the Hervey Group for the palaeoenvironment and evolution of Devonian tetrapods and fish. Late Devonian palaeosols of the Hervey Group in New South Wales formed in a semiarid climate with low shrubby desert vegetation, but at two levels including one with a tetrapod, there is evidence of subhumid woodland. That double spike to subhumid climate matches palaeoclimatic spikes in Pennsylvania cued to global atmospheric spikes in carbon dioxide correlated with the Annulata event of marine black shales dated at 365 Ma. This evidence supports the woodland hypothesis of tetrapod origins rather than the idea that they evolved from fish escaping shrinking desert ponds, or evolved in tidal flats. The Canowindra fish bed of mass mortality in a desiccated billabong (oxbow lake) is a stunning example of what happened in drying desert ponds. New South Wales has no clear evidence of intertidal vertebrates, and trackways which inspired this hypothesis are now controversial. In otherwise aquatic Late Devonian tetrapods, limbs may have been adaptations to negotiating or hiding from predators in streams choked with woody debris, and their necks allowed feeding on land, or in water shallower than their bodies.",
    url = "https://doi.org/10.18261/let.57.1.5",
    doi = "10.18261/let.57.1.5",
    openalex = "W4392354543",
    references = "doi101029tc007i003p00351"
}

Actinopterygii is a major extant vertebrate group, but limited data are available for its earliest members. Here we investigate the morphology of Devonian actinopterygians, focusing on the lower jaw. We use X-ray computed tomography (XCT) to provide comprehensive descriptions of the mandibles of 19 species, which span the whole of the Devonian and represent roughly two-thirds of all taxa known from more than isolated or fragmentary material. Our findings corroborate previous reports in part but reveal considerable new anatomical data and represent the first detailed description for roughly half of these taxa. The mandibles display substantial variation in size, spanning more than an order of magnitude. Although most conform to a generalized pattern of a large dentary and one or two smaller infradentaries, XCT data reveal significant differences in the structure of the jaw and arrangement of teeth that may be of functional relevance. We report the presence of a rudimentary coronoid process in several taxa, contributed to by the dentary and/or infradentaries, as well a raised articular region, resulting in a mandible with an offset bite and that functions as a bent level arm. Among the most striking variation is that of tooth morphology: several taxa have heterodont dentary teeth that vary in size and orientation, and multiple variations on enlarged, whorl-like and posteriorly-oriented anterior coronoid dentition are observed. We use these new data to revise morphological characters that may be of phylogenetic significance and consider the possible functional implicationds of these traits. The observed variation in mandible form and structure suggests previously unappreciated functional diversity among otherwise morphologically homogenous Devonian ray-finned fishes.

@article{doi101002ar70005,
    author = "Igielman, Ben and Figueroa, Rodrigo Tinoco and Higgins, Robert and Pierce, Stephanie E. and Coates, Michael I. and Troyer, Emily M. and Fernández, Vincent and Dollman, Kathleen and Lü, Jing and Zhu, Min and Friedman, Matt and Giles, Sam",
    title = "The lower jaw of Devonian ray‐finned fishes (Actinopterygii): Anatomy, relationships, and functional morphology",
    year = "2025",
    journal = "The Anatomical Record",
    abstract = "Actinopterygii is a major extant vertebrate group, but limited data are available for its earliest members. Here we investigate the morphology of Devonian actinopterygians, focusing on the lower jaw. We use X-ray computed tomography (XCT) to provide comprehensive descriptions of the mandibles of 19 species, which span the whole of the Devonian and represent roughly two-thirds of all taxa known from more than isolated or fragmentary material. Our findings corroborate previous reports in part but reveal considerable new anatomical data and represent the first detailed description for roughly half of these taxa. The mandibles display substantial variation in size, spanning more than an order of magnitude. Although most conform to a generalized pattern of a large dentary and one or two smaller infradentaries, XCT data reveal significant differences in the structure of the jaw and arrangement of teeth that may be of functional relevance. We report the presence of a rudimentary coronoid process in several taxa, contributed to by the dentary and/or infradentaries, as well a raised articular region, resulting in a mandible with an offset bite and that functions as a bent level arm. Among the most striking variation is that of tooth morphology: several taxa have heterodont dentary teeth that vary in size and orientation, and multiple variations on enlarged, whorl-like and posteriorly-oriented anterior coronoid dentition are observed. We use these new data to revise morphological characters that may be of phylogenetic significance and consider the possible functional implicationds of these traits. The observed variation in mandible form and structure suggests previously unappreciated functional diversity among otherwise morphologically homogenous Devonian ray-finned fishes.",
    url = "https://doi.org/10.1002/ar.70005",
    doi = "10.1002/ar.70005",
    openalex = "W4412548413",
    references = "doi101038s41559022019194, doi101098rsos171727"
}

Abstract Actinopterygii is a major extant vertebrate group, but limited data are available for its earliest members. Here we investigate the morphology of Devonian actinopterygians, focusing on the lower jaw. We use X-Ray Computed Tomography (XCT) to provide comprehensive descriptions of the mandibles of 19 species, which span the whole of the Devonian and represent roughly two thirds of all taxa known from more than isolated or fragmentary material. Our findings corroborate previous reports in part but reveal considerable new anatomical data and represent the first detailed description for roughly half of these taxa. The mandibles display substantial variation in size, spanning more than an order of magnitude. Although most conform to a generalized pattern of a large dentary and one or two smaller infradentaries, XCT data reveal significant differences in the structure of the jaw and arrangement of teeth that may be of functional relevance. We report the presence of a rudimentary coronoid process in several taxa, contributed to by the dentary and/or infradentaries, as well a raised articular region, resulting in a mandible with an offset bite and that functions as a bent level arm. Among the most striking variation is that of tooth morphology: several taxa have heterodont dentary teeth that vary in size and orientation, and multiple variations on enlarged, whorl-like and posteriorly-oriented anterior coronoid dentition are observed. We use these new data to revise morphological characters that may be of phylogenetic significance and consider the possible functional implications of these traits. The observed variation in mandible form and structure suggests previously unappreciated functional diversity among otherwise morphologically homogenous Devonian ray-finned fishes.

@misc{doi10110120250130635695,
    author = "Igielman, Ben and Figueroa, Rodrigo Tinoco and Higgins, Robert R and Pierce, Stephanie E. and Coates, Michael I. and Troyer, Emily M. and Fernández, Vincent and Dollman, Kathleen and Lü, Jing and Zhu, Min and Friedman, Matt and Giles, Sam",
    title = "The lower jaw of Devonian ray-finned fishes (Actinopterygii): anatomy, relationships, and functional morphology",
    year = "2025",
    booktitle = "bioRxiv (Cold Spring Harbor Laboratory)",
    abstract = "Abstract Actinopterygii is a major extant vertebrate group, but limited data are available for its earliest members. Here we investigate the morphology of Devonian actinopterygians, focusing on the lower jaw. We use X-Ray Computed Tomography (XCT) to provide comprehensive descriptions of the mandibles of 19 species, which span the whole of the Devonian and represent roughly two thirds of all taxa known from more than isolated or fragmentary material. Our findings corroborate previous reports in part but reveal considerable new anatomical data and represent the first detailed description for roughly half of these taxa. The mandibles display substantial variation in size, spanning more than an order of magnitude. Although most conform to a generalized pattern of a large dentary and one or two smaller infradentaries, XCT data reveal significant differences in the structure of the jaw and arrangement of teeth that may be of functional relevance. We report the presence of a rudimentary coronoid process in several taxa, contributed to by the dentary and/or infradentaries, as well a raised articular region, resulting in a mandible with an offset bite and that functions as a bent level arm. Among the most striking variation is that of tooth morphology: several taxa have heterodont dentary teeth that vary in size and orientation, and multiple variations on enlarged, whorl-like and posteriorly-oriented anterior coronoid dentition are observed. We use these new data to revise morphological characters that may be of phylogenetic significance and consider the possible functional implications of these traits. The observed variation in mandible form and structure suggests previously unappreciated functional diversity among otherwise morphologically homogenous Devonian ray-finned fishes.",
    url = "https://doi.org/10.1101/2025.01.30.635695",
    doi = "10.1101/2025.01.30.635695",
    openalex = "W4407179632",
    references = "doi101038s41559022019194"
}