Megalosaurids

I. I ntroduction. T he object of the present communication is to show the development and sequence of certain Jurassic strata on the Dorset coast, and to make some comparisons with strata elsewhere. The range of strata dealt with is from the top of the Middle Lias (Pliensbachian) to the lower part of the Fullers' Earth (Bathonian, Vesulian) inclusive. The communication is laid before the Society for several reasons: it was promised many years ago; it forms a sequence to the papers on North Dorset and the Cotteswolds; it aims to give a detailed account of certain fossiliferous strata of South Dorset, to be used as a foundation for the dating of the fossils; and it offers suggestions in the matter of correlation and subdivision as a basis for the work of other investigators. With this stratigraphical paper there is also offered a palæontological paper, to describe some of the new species mentioned, and to figure some other species which are new and illustrative of strata of the same dates. That communication will be alluded to as ‘the palæontological paper.’ The investigations for this paper, which will probably be my last, so far as active field-geology is concerned, were complete in the main several years ago; it was announced in 1893 as nearly ready for publication. Since then changes of residence have involved packing of specimens, and many have not been unpacked again. As a consequence the identification of species must often be given in general terms, as they were set out

@article{doi101144gsljgs1910066010405,
    author = "Buckman, S. S.",
    title = "Certain Jurassic (Lias-Oolite) Strata of South Dorset; and their Correlation",
    year = "1910",
    journal = "Quarterly Journal of the Geological Society",
    abstract = "I. I ntroduction. T he object of the present communication is to show the development and sequence of certain Jurassic strata on the Dorset coast, and to make some comparisons with strata elsewhere. The range of strata dealt with is from the top of the Middle Lias (Pliensbachian) to the lower part of the Fullers' Earth (Bathonian, Vesulian) inclusive. The communication is laid before the Society for several reasons: it was promised many years ago; it forms a sequence to the papers on North Dorset and the Cotteswolds; it aims to give a detailed account of certain fossiliferous strata of South Dorset, to be used as a foundation for the dating of the fossils; and it offers suggestions in the matter of correlation and subdivision as a basis for the work of other investigators. With this stratigraphical paper there is also offered a palæontological paper, to describe some of the new species mentioned, and to figure some other species which are new and illustrative of strata of the same dates. That communication will be alluded to as ‘the palæontological paper.’ The investigations for this paper, which will probably be my last, so far as active field-geology is concerned, were complete in the main several years ago; it was announced in 1893 as nearly ready for publication. Since then changes of residence have involved packing of specimens, and many have not been unpacked again. As a consequence the identification of species must often be given in general terms, as they were set out",
    url = "https://doi.org/10.1144/gsl.jgs.1910.066.01-04.05",
    doi = "10.1144/gsl.jgs.1910.066.01-04.05",
    openalex = "W2098206526"
}

A lthough the carnivorous Dinosaur Megalosaurus was first discovered in the Stonesfield Slate nearly 80 years ago, and is now represented by numerous fossils from the Bathonian and later Mesozoic formations of England, its skull has hitherto been known only by unsatisfactory fragments of jaws. Our acquaintance with the Megalosaurian type of skull has depended solely on discoveries of nearly complete specimens in the Jurassic and Cretaceous formations of North America. At last, however, Mr. F. Lewis Bradley, F.G.S., has been able to submit to the Society the greater part of a skull obtained some time ago from the Great Oolite in an excavation for a reservoir at Minchinhampton (Gloucestershire); and he has prepared the specimen with so much skill and success that it is beautifully exposed for study from the left side (Pl. XIII, fig. 1). It is rather small, measuring only 26 centimetres in total length, but there cannot be much doubt that it belongs to the genus Megallosaurus itself. The upper portion of the fossil is unfortunately destroyed by an irregular fissure in the rock, which is partly filled with calcite. The cranium is, therefore, scarcely seen; but there are traces behind of the occiput, which is somewhat deeper than wide above the foramen magnum, and lies in a plane inclined much forwards. The external bones of the temporal region and face are remarkably thin and delicate, and in their crushed condition it is difficult to distinguish the sutures between them. The large vacuities, however, which form so

@article{woodward1910on,
    author = "Woodward, Arthur Smith",
    title = "On a Skull of Megalosaurus from the Great Oolite of Minchinhampton (Gloucestershire)",
    year = "1910",
    journal = "Quarterly Journal of the Geological Society of London",
    abstract = "A lthough the carnivorous Dinosaur Megalosaurus was first discovered in the Stonesfield Slate nearly 80 years ago, and is now represented by numerous fossils from the Bathonian and later Mesozoic formations of England, its skull has hitherto been known only by unsatisfactory fragments of jaws. Our acquaintance with the Megalosaurian type of skull has depended solely on discoveries of nearly complete specimens in the Jurassic and Cretaceous formations of North America. At last, however, Mr. F. Lewis Bradley, F.G.S., has been able to submit to the Society the greater part of a skull obtained some time ago from the Great Oolite in an excavation for a reservoir at Minchinhampton (Gloucestershire); and he has prepared the specimen with so much skill and success that it is beautifully exposed for study from the left side (Pl. XIII, fig. 1). It is rather small, measuring only 26 centimetres in total length, but there cannot be much doubt that it belongs to the genus Megallosaurus itself. The upper portion of the fossil is unfortunately destroyed by an irregular fissure in the rock, which is partly filled with calcite. The cranium is, therefore, scarcely seen; but there are traces behind of the occiput, which is somewhat deeper than wide above the foramen magnum, and lies in a plane inclined much forwards. The external bones of the temporal region and face are remarkably thin and delicate, and in their crushed condition it is difficult to distinguish the sutures between them. The large vacuities, however, which form so",
    url = "https://doi.org/10.1144/gsl.jgs.1910.066.01-04.07",
    doi = "10.1144/gsl.jgs.1910.066.01-04.07",
    number = "1-4",
    openalex = "W2039538269",
    pages = "111-115",
    volume = "66"
}

@article{woodward1910on2,
    author = "Woodward, A. S",
    title = "On a skull of Megalosaurus from the Great Oolite of Minchinhampton (Gloucestershire)",
    year = "1910",
    journal = "Quarterly Journal of the Geological Society, London, v. 66, p. 111-115",
    note = "talkorigins\_source = {true}; raw\_reference = {Woodward, A. S., 1910, On a skull of Megalosaurus from the Great Oolite of Minchinhampton (Gloucestershire): Quarterly Journal of the Geological Society, London, v. 66, p. 111-115.}"
}

@misc{waldman1974megalosaurids1,
    author = "Waldman, M",
    title = "Megalosaurids from the Bajocian (Middle Jurassic) of Dorset",
    year = "1974",
    howpublished = "Palaeontology, v. 17, p. 325-339",
    note = "talkorigins\_source = {true}; raw\_reference = {Waldman, M., 1974, Megalosaurids from the Bajocian (Middle Jurassic) of Dorset: Palaeontology, v. 17, p. 325-339.}"
}

The marine Bajocian Taberna Formation of west-central Oaxaca consists mainly of shale, intercalated siltstone, and frequent iron concretions with ammonites. This formation overlies the continental Zorrillo Formation and is overlain by the continental to subcontinental Simon and Otatera formations. The best outcrops are in the area of Mixtepec and Diquiyú-Yutatio. Two new ammonite biozones are distinguished: Duashnoceras floresi Range Zone (≃ upper Humphriesianum-lower Subfurcatum standard zones), and Parastrenoceras zapotecum Assemblage Zone (≃ Subfurcatum Standard Zone). The biogeographic affinities are principally with the Mediterranean Province, and also with both the East-Pacific Andean and North Cordilleran provinces. A high percentage of species is endemic. The Stephanoceratinae, mainly Duashnoceras, are dominant in the D. floresi Zone, which also includes Subcollina lucretia, Strigoceras (Liroxyites), Stephanoceras, Phaulostephanus, Stephanosphinctes, and Oppelia. Parastrenoceras and Leptosphinctes are dominant in the P. zapotecum Zone, whereas Oppelia and Strigoceras are less abundant. Stephanosphinctes n. gen., type species S. buitroni n. sp., is intermediate between the Stephanoceratinae and Leptosphinctinae. The species Phaulostephanus burckhardti is also new.

@article{doi101017s0022336000002985,
    author = "Sandoval, José and Westermann, Gerd E. G.",
    title = "The Bajocian (Jurassic) ammonite fauna of Oaxaca, Mexico",
    year = "1986",
    journal = "Journal of Paleontology",
    abstract = "The marine Bajocian Taberna Formation of west-central Oaxaca consists mainly of shale, intercalated siltstone, and frequent iron concretions with ammonites. This formation overlies the continental Zorrillo Formation and is overlain by the continental to subcontinental Simon and Otatera formations. The best outcrops are in the area of Mixtepec and Diquiyú-Yutatio. Two new ammonite biozones are distinguished: Duashnoceras floresi Range Zone (≃ upper Humphriesianum-lower Subfurcatum standard zones), and Parastrenoceras zapotecum Assemblage Zone (≃ Subfurcatum Standard Zone). The biogeographic affinities are principally with the Mediterranean Province, and also with both the East-Pacific Andean and North Cordilleran provinces. A high percentage of species is endemic. The Stephanoceratinae, mainly Duashnoceras, are dominant in the D. floresi Zone, which also includes Subcollina lucretia, Strigoceras (Liroxyites), Stephanoceras, Phaulostephanus, Stephanosphinctes, and Oppelia. Parastrenoceras and Leptosphinctes are dominant in the P. zapotecum Zone, whereas Oppelia and Strigoceras are less abundant. Stephanosphinctes n. gen., type species S. buitroni n. sp., is intermediate between the Stephanoceratinae and Leptosphinctinae. The species Phaulostephanus burckhardti is also new.",
    url = "https://doi.org/10.1017/s0022336000002985",
    doi = "10.1017/s0022336000002985",
    openalex = "W2478716650"
}

For the purposes of a high-resolution multi-disciplinary study of the Upper Jurassic Kimmeridge Clay Formation, two boreholes were drilled at Swanworth Quarry and one at Metherhills, south Dorset, UK. Together, the cores represent the first complete section through the entire formation close to the type section. We present graphic logs that record the stratigraphy of the cores, and outline the complementary geophysical and analytical data sets (gamma ray, magnetic susceptibility, total organic carbon, carbonate, δ 13 C org). Of particular note are the new borehole data from the lowermost part of the formation which does not crop out in the type area. Detailed logs are available for download from the Kimmeridge Drilling Project web-site at http://kimmeridge.earth.ox.ac.uk/. Of further interest is a mid- eudoxus Zone positive shift in the δ 13 C org record, a feature that is also registered in Tethyan carbonate successions, suggesting that it is a regional event and may therefore be useful for correlation. The lithostratigraphy of the cores has been precisely correlated with the nearby cliff section, which has also been examined and re-described. Magnetic-susceptibility and spectral gamma-ray measurements were made at a regular spacing through the succession, and facilitate core-to-exposure correlation. The strata of the exposure and core have been subdivided into four main mudrock lithological types: (a) medium-dark–dark-grey marl; (b) medium-dark–dark grey–greenish black shale; (c) dark-grey–olive-black laminated shale; (d) greyish-black–brownish-black mudstone. The sections also contain subordinate amounts of siltstone, limestone and dolostone. Comparison of the type section with the cores reveals slight lithological variation and notable thickness differences between the coeval strata. The proximity of the boreholes and different parts of the type section to the Purbeck–Isle of Wight Disturbance is proposed as a likely control on the thickness changes.

@article{doi101017s0016756801005738,
    author = "Morgans‐Bell, Helen S. and Coe, Angela L. and Hesselbo, Stephen P. and Jenkyns, Hugh C. and Weedon, Graham P. and Marshall, John and Tyson, Richard V. and Williams, C.J.",
    title = "Integrated stratigraphy of the Kimmeridge Clay Formation (Upper Jurassic) based on exposures and boreholes in south Dorset, UK",
    year = "2001",
    journal = "Geological Magazine",
    abstract = "For the purposes of a high-resolution multi-disciplinary study of the Upper Jurassic Kimmeridge Clay Formation, two boreholes were drilled at Swanworth Quarry and one at Metherhills, south Dorset, UK. Together, the cores represent the first complete section through the entire formation close to the type section. We present graphic logs that record the stratigraphy of the cores, and outline the complementary geophysical and analytical data sets (gamma ray, magnetic susceptibility, total organic carbon, carbonate, δ 13 C org). Of particular note are the new borehole data from the lowermost part of the formation which does not crop out in the type area. Detailed logs are available for download from the Kimmeridge Drilling Project web-site at http://kimmeridge.earth.ox.ac.uk/. Of further interest is a mid- eudoxus Zone positive shift in the δ 13 C org record, a feature that is also registered in Tethyan carbonate successions, suggesting that it is a regional event and may therefore be useful for correlation. The lithostratigraphy of the cores has been precisely correlated with the nearby cliff section, which has also been examined and re-described. Magnetic-susceptibility and spectral gamma-ray measurements were made at a regular spacing through the succession, and facilitate core-to-exposure correlation. The strata of the exposure and core have been subdivided into four main mudrock lithological types: (a) medium-dark–dark-grey marl; (b) medium-dark–dark grey–greenish black shale; (c) dark-grey–olive-black laminated shale; (d) greyish-black–brownish-black mudstone. The sections also contain subordinate amounts of siltstone, limestone and dolostone. Comparison of the type section with the cores reveals slight lithological variation and notable thickness differences between the coeval strata. The proximity of the boreholes and different parts of the type section to the Purbeck–Isle of Wight Disturbance is proposed as a likely control on the thickness changes.",
    url = "https://doi.org/10.1017/s0016756801005738",
    doi = "10.1017/s0016756801005738",
    openalex = "W2111363534",
    references = "doi101144gsjgs14820245"
}

A dinosaur braincase from the Middle Jurassic (Bathonian) of Oxfordshire (England) is described. The specimen, which has historical significance, has been erratically attributed to either a sauropod or a theropod on the basis of vague phenetic resemblances. It is here re-interpreted in the light of recent cladistic analyses of dinosaurs, allowing the first proper character-based discussion of its affinities. It resembles those of ornithischian and prosauropod dinosaurs in the absence of a prominent, caudolaterally directed bony sheet from either the crista tuberalis (as in all theropods) or the crista prootica (as in all sauropods except juveniles of the eusauropod Shunosaurus). This braincase shows two synapomorphic characters of the Eusauropoda: the region of the cranium is rostrocaudally shortened and the long axis of the supratemporal fenestra is transversely oriented. For these characters, ornithischians, theropods, and prosauropods retain the plesiomorphic condition. It is concluded that the specimen is an important exemplar of a Middle Jurassic sauropod braincase and it is suggested that it could be from the eusauropod Cetiosaurus.

@article{doi101017s0016756806002561,
    author = "Galton, P. and Knoll, Fabien",
    title = "A saurischian dinosaur braincase from the Middle Jurassic (Bathonian) near Oxford, England: from the theropod Megalosaurus or the sauropod Cetiosaurus?",
    year = "2006",
    journal = "Geological Magazine",
    abstract = "A dinosaur braincase from the Middle Jurassic (Bathonian) of Oxfordshire (England) is described. The specimen, which has historical significance, has been erratically attributed to either a sauropod or a theropod on the basis of vague phenetic resemblances. It is here re-interpreted in the light of recent cladistic analyses of dinosaurs, allowing the first proper character-based discussion of its affinities. It resembles those of ornithischian and prosauropod dinosaurs in the absence of a prominent, caudolaterally directed bony sheet from either the crista tuberalis (as in all theropods) or the crista prootica (as in all sauropods except juveniles of the eusauropod Shunosaurus). This braincase shows two synapomorphic characters of the Eusauropoda: the region of the cranium is rostrocaudally shortened and the long axis of the supratemporal fenestra is transversely oriented. For these characters, ornithischians, theropods, and prosauropods retain the plesiomorphic condition. It is concluded that the specimen is an important exemplar of a Middle Jurassic sauropod braincase and it is suggested that it could be from the eusauropod Cetiosaurus.",
    url = "https://www.semanticscholar.org/paper/cabffee09ef6fbb34356500fa1837fd44b87dfdc",
    doi = "10.1017/S0016756806002561",
    is_oa = "true",
    number = "6",
    pages = "905-921",
    semanticscholar_citation_count = "18",
    semanticscholar_id = "cabffee09ef6fbb34356500fa1837fd44b87dfdc",
    volume = "143"
}

‘Megalosaurus’ hesperis from the Inferior Oolite (Bajocian, Middle Jurassic) of Dorset, UK is redescribed. Several features of ‘M.’ hesperis demonstrate that it is distinct from the lectotype dentary of Megalosaurus: an enlarged, subcircular third alveolus and subcylindrical, anteriorly inclined anterior dentary teeth; an anterior Meckelian foramen located almost directly anterior to the posterior Meckelian foramen; low interdental plates; and a prominent lip bounding the Meckelian groove ventrally, anterior to the Meckelian fossa. Therefore a new genus, Duriavenator, is erected to form the new combination D. hesperis. D. hesperis possesses two autapomorphies of the maxilla: a deep groove on dorsal surface of the jugal process containing numerous pneumatic foramina; and an array of small foramina in the ventral part of the articular surface for the premaxilla. Several features confirm the tetanuran affinities of D. hesperis: a prominent anterior process of the maxilla; the presence of band-like dental enamel wrinkles; the maxillary 'fenestra' is present but takes the form of an imperforate fossa (a spinosauroid synapomorphy); and the paradental groove is wide anteriorly, defining a distinct gap between the interdental plates and the medial wall of the dentary (a synapomorphy of Spinosauridae + Megalosauridae). Older records of tetanurans have been proposed, but most of these have been refuted and detailed re-examination of other early reports is warranted to establish the date of origin of this clade. An early Middle Jurassic origin of tetanurans is preferred.

@article{benson2008a,
    author = "BENSON, ROGER B. J.",
    title = "A redescription of 'Megalosaurus' hesperis (Dinosauria, Theropoda) from the Inferior Oolite (Bajocian, Middle Jurassic) of Dorset, United Kingdom",
    year = "2008",
    journal = "Zootaxa",
    abstract = "‘Megalosaurus’ hesperis from the Inferior Oolite (Bajocian, Middle Jurassic) of Dorset, UK is redescribed. Several features of ‘M.’ hesperis demonstrate that it is distinct from the lectotype dentary of Megalosaurus: an enlarged, subcircular third alveolus and subcylindrical, anteriorly inclined anterior dentary teeth; an anterior Meckelian foramen located almost directly anterior to the posterior Meckelian foramen; low interdental plates; and a prominent lip bounding the Meckelian groove ventrally, anterior to the Meckelian fossa. Therefore a new genus, Duriavenator, is erected to form the new combination D. hesperis. D. hesperis possesses two autapomorphies of the maxilla: a deep groove on dorsal surface of the jugal process containing numerous pneumatic foramina; and an array of small foramina in the ventral part of the articular surface for the premaxilla. Several features confirm the tetanuran affinities of D. hesperis: a prominent anterior process of the maxilla; the presence of band-like dental enamel wrinkles; the maxillary 'fenestra' is present but takes the form of an imperforate fossa (a spinosauroid synapomorphy); and the paradental groove is wide anteriorly, defining a distinct gap between the interdental plates and the medial wall of the dentary (a synapomorphy of Spinosauridae + Megalosauridae). Older records of tetanurans have been proposed, but most of these have been refuted and detailed re-examination of other early reports is warranted to establish the date of origin of this clade. An early Middle Jurassic origin of tetanurans is preferred.",
    url = "https://doi.org/10.11646/zootaxa.1931.1.5",
    doi = "10.11646/zootaxa.1931.1.5",
    number = "1",
    openalex = "W1005905333",
    volume = "1931",
    references = "doi105281zenodo5373094"
}

Megalosaurus bucklandii (Dinosauria: Theropoda), the oldest named dinosaur taxon, from the Bathonian (Middle Jurassic) of England, is a valid taxon diagnosed by a unique character combination of the lectotype dentary. Abundant referred material is described and several autapomorphies are identified: ventral surfaces of first and third to fifth sacral centra evenly rounded, ventral surface of second sacral centrum bearing longitudinal, angular ridge; dorsally directed flange around midheight on the scapular blade; an array of posterodorsally inclined grooves on the lateral surface of the median iliac ridge; anteroposteriorly thick ischial apron with an almost flat medial surface; and complementary groove and ridge structures on the articular surfaces between metatarsals II and III.

@article{doi101111j10963642200900569x,
    author = "Benson, Roger",
    title = "A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods",
    year = "2009",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Megalosaurus bucklandii (Dinosauria: Theropoda), the oldest named dinosaur taxon, from the Bathonian (Middle Jurassic) of England, is a valid taxon diagnosed by a unique character combination of the lectotype dentary. Abundant referred material is described and several autapomorphies are identified: ventral surfaces of first and third to fifth sacral centra evenly rounded, ventral surface of second sacral centrum bearing longitudinal, angular ridge; dorsally directed flange around midheight on the scapular blade; an array of posterodorsally inclined grooves on the lateral surface of the median iliac ridge; anteroposteriorly thick ischial apron with an almost flat medial surface; and complementary groove and ridge structures on the articular surfaces between metatarsals II and III.",
    url = "https://doi.org/10.1111/j.1096-3642.2009.00569.x",
    doi = "10.1111/j.1096-3642.2009.00569.x",
    openalex = "W2019441231",
    references = "benson2008a, crossref1976allosaurus, doi10108002724634199710011027, doi10108002724634199910011178, doi101111j109600311999tb00277x, doi101126science2725264986, doi101126science28454232137, doi102475ajss31695411, doi102475ajss319111253, doi105281zenodo16171435, doi105281zenodo5373094, openalexw3215057009, woodward1910on"
}

The Stratigraphy Committee of the British Geological Survey (BGS) is undertaking a review of stratigraphical classification for all parts of Great Britain. Several Stratigraphical Framework Committees (SFC) have been established to review problematical issues for various parts of the stratigraphical column. Each SFC has the following terms of reference: • To review the lithostratigraphical nomenclature of designated stratigraphical intervals for a given region, identifying problems in classification and correlation. • To propose a lithostratigraphical framework down to formation level that can be used as a central reference by geologists working in the region concerned. • To organise peer review of the scheme. • To present the results in a document suitable for publication. • To ensure that full definitions of the lithostratigraphical units are held in the web-accessible BGS Lexicon of Named Rock Units for the areas of responsibility covered by the SFC. The process of erecting a framework requires decisions to be taken about correlations and equivalences leading to a simplified nomenclature. Inevitably, many names will be rendered obsolete. The frameworks are lithostratigraphical and though each is set against a chronostratigraphical reference column, the finer points of the chronostratigraphy of the succession are not the prime concern. The predominantly Middle Jurassic rocks discussed in this report have been considered by the Jurassic Stratigraphical Framework Committee under the leadership initially of M G Sumbler (who compiled an initial draft in 2003) and, after 2001, A J M Barron. The report introduces a lithostratigraphical framework to formation level for the Middle Jurassic succession of Britain and adjoining offshore areas. It applies to the main outcrops and subcrops (where the strata are present at depth), and the offshore occurrences. It follows on, with an extended geographical brief, from the stratigraphical framework report for the Lower Jurassic of England and Wales (Cox et al., 1999). The onshore distribution has been divided into six depositional areas; the Wessex–Weald Basin, the Cotswolds, the East Midlands Shelf, the Cleveland Basin, the Moray Firth and the Hebrides, although for practical reasons the essentially arbitrary lateral limits of the first three may differ for various stratigraphical levels. The economic importance and availability of natural and man-made exposures of Middle Jurassic strata has resulted in well over 200 years of research attempting to classify them. Much of this work occurred long before guidance was available for best practice in naming lithostratigraphical units, and there has been a haphazard approach to the establishment of the hierarchy of units. From an early, relatively simple framework, subsequent publications have greatly added to the complexity of the nomenclature. Often this reflected the localised nature of research with different names being applied to essentially the same unit in different areas. Also, previously laterally contiguous deposits have been separated, eroded or concealed by post-Jurassic tectonic, igneous or sedimentary events and processes. Chapter 1 of this report is an introduction to the Middle Jurassic Series and the included proposals. It indicates the principles for the development of the new lithostratigraphical scheme and sets out the key publications used for reference. Chapter 2 summarises the structural and palaeogeographical setting of Great Britain through the Middle Jurassic and sets out the definitions, history and development of the basins. Chapter 3 briefly describes the key techniques (principally biostratigraphy) for correlation of successions, and sets out the basis for the establishment of the chronostratigraphical framework. Chapter 4 outlines the development of the lithostratigraphical framework. The fifth (Chapters 5 to 8) and largest part of the report provides a fuller description of the stratigraphical framework for each of the six onshore groups – the Inferior Oolite, Great Oolite, Ravenscar and Ancholme groups in England, and the Great Estuarine and Sutherland groups in Scotland, subdivided as appropriate into regions and/or palaeogeographical provinces. Each entry includes a description of the origin and history of the nomenclature, rank and subdivisions, principal lithologies, type area and reference sections, geographical extent, lower and upper boundary, thickness, age range, environment of deposition and key references. Chapter 9 gives a concise account of the framework for the offshore regions, related to the onshore sequences. Definitions of the offshore Fladen, West Sole, Brent and Humber groups and their component formations are not given as the full schemes are formally and satisfactorily published elsewhere (Lott and Knox, 1994; Richards et al., 1993; Ritchie et al., 1996).

@article{openalexw1920561902,
    author = "Barron, A.J.M. and Lott, G.K. and Riding, James B.",
    title = "Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf",
    year = "2012",
    abstract = "The Stratigraphy Committee of the British Geological Survey (BGS) is undertaking a review of stratigraphical classification for all parts of Great Britain. Several Stratigraphical Framework Committees (SFC) have been established to review problematical issues for various parts of the stratigraphical column. Each SFC has the following terms of reference: • To review the lithostratigraphical nomenclature of designated stratigraphical intervals for a given region, identifying problems in classification and correlation. • To propose a lithostratigraphical framework down to formation level that can be used as a central reference by geologists working in the region concerned. • To organise peer review of the scheme. • To present the results in a document suitable for publication. • To ensure that full definitions of the lithostratigraphical units are held in the web-accessible BGS Lexicon of Named Rock Units for the areas of responsibility covered by the SFC. The process of erecting a framework requires decisions to be taken about correlations and equivalences leading to a simplified nomenclature. Inevitably, many names will be rendered obsolete. The frameworks are lithostratigraphical and though each is set against a chronostratigraphical reference column, the finer points of the chronostratigraphy of the succession are not the prime concern. The predominantly Middle Jurassic rocks discussed in this report have been considered by the Jurassic Stratigraphical Framework Committee under the leadership initially of M G Sumbler (who compiled an initial draft in 2003) and, after 2001, A J M Barron. The report introduces a lithostratigraphical framework to formation level for the Middle Jurassic succession of Britain and adjoining offshore areas. It applies to the main outcrops and subcrops (where the strata are present at depth), and the offshore occurrences. It follows on, with an extended geographical brief, from the stratigraphical framework report for the Lower Jurassic of England and Wales (Cox et al., 1999). The onshore distribution has been divided into six depositional areas; the Wessex–Weald Basin, the Cotswolds, the East Midlands Shelf, the Cleveland Basin, the Moray Firth and the Hebrides, although for practical reasons the essentially arbitrary lateral limits of the first three may differ for various stratigraphical levels. The economic importance and availability of natural and man-made exposures of Middle Jurassic strata has resulted in well over 200 years of research attempting to classify them. Much of this work occurred long before guidance was available for best practice in naming lithostratigraphical units, and there has been a haphazard approach to the establishment of the hierarchy of units. From an early, relatively simple framework, subsequent publications have greatly added to the complexity of the nomenclature. Often this reflected the localised nature of research with different names being applied to essentially the same unit in different areas. Also, previously laterally contiguous deposits have been separated, eroded or concealed by post-Jurassic tectonic, igneous or sedimentary events and processes. Chapter 1 of this report is an introduction to the Middle Jurassic Series and the included proposals. It indicates the principles for the development of the new lithostratigraphical scheme and sets out the key publications used for reference. Chapter 2 summarises the structural and palaeogeographical setting of Great Britain through the Middle Jurassic and sets out the definitions, history and development of the basins. Chapter 3 briefly describes the key techniques (principally biostratigraphy) for correlation of successions, and sets out the basis for the establishment of the chronostratigraphical framework. Chapter 4 outlines the development of the lithostratigraphical framework. The fifth (Chapters 5 to 8) and largest part of the report provides a fuller description of the stratigraphical framework for each of the six onshore groups – the Inferior Oolite, Great Oolite, Ravenscar and Ancholme groups in England, and the Great Estuarine and Sutherland groups in Scotland, subdivided as appropriate into regions and/or palaeogeographical provinces. Each entry includes a description of the origin and history of the nomenclature, rank and subdivisions, principal lithologies, type area and reference sections, geographical extent, lower and upper boundary, thickness, age range, environment of deposition and key references. Chapter 9 gives a concise account of the framework for the offshore regions, related to the onshore sequences. Definitions of the offshore Fladen, West Sole, Brent and Humber groups and their component formations are not given as the full schemes are formally and satisfactorily published elsewhere (Lott and Knox, 1994; Richards et al., 1993; Ritchie et al., 1996).",
    openalex = "W1920561902",
    references = "doi101144gsljgs1893049010460, openalexw2793832558"
}

The “stipites” are Bathonian (Middle Jurassic) coals that formed in an everglades-like environment and are now exposed in the Grands Causses (southern France). The vertebrate assemblage of the “stipites” and of the transitional layers to the carbonates in which they are interspersed are reviewed. To date, only small-sized and isolated vertebrate bones, teeth, and scales have been recovered. These record the presence of sharks (Hybodus, Asteracanthus), bony fishes (Lepidotes, Pycnodontiformes, Caturus, Aspidorhynchus), amphibians (Anura, Albanerpetontidae), and reptiles (Crocodylomorpha, Ornithischia, Theropoda). Despite its relatively limited taxonomic diversity, the vertebrate assemblage from the “stipites” and from their associated layers is notable for being one of the few of this age with both terrestrial and marine influences. Compared to other approximately coeval formations in Western Europe, the “stipites” vertebrate assemblage is surpassed in diversity only by those from the British Isles.

@article{doi103389fevo201400048,
    author = "Knoll, Fabien and pez-Antoñanzas, Raquel LÃ",
    title = "The vertebrate fauna from the “stipite†layers of the Grands Causses (Middle Jurassic, France)",
    year = "2014",
    journal = "Frontiers in Ecology and Evolution",
    abstract = "The “stipites” are Bathonian (Middle Jurassic) coals that formed in an everglades-like environment and are now exposed in the Grands Causses (southern France). The vertebrate assemblage of the “stipites” and of the transitional layers to the carbonates in which they are interspersed are reviewed. To date, only small-sized and isolated vertebrate bones, teeth, and scales have been recovered. These record the presence of sharks (Hybodus, Asteracanthus), bony fishes (Lepidotes, Pycnodontiformes, Caturus, Aspidorhynchus), amphibians (Anura, Albanerpetontidae), and reptiles (Crocodylomorpha, Ornithischia, Theropoda). Despite its relatively limited taxonomic diversity, the vertebrate assemblage from the “stipites” and from their associated layers is notable for being one of the few of this age with both terrestrial and marine influences. Compared to other approximately coeval formations in Western Europe, the “stipites” vertebrate assemblage is surpassed in diversity only by those from the British Isles.",
    url = "https://doi.org/10.3389/fevo.2014.00048",
    doi = "10.3389/fevo.2014.00048",
    openalex = "W2160275538",
    references = "doi1010160031018279901639, doi101073pnas1203238109, doi10108002724634199510011272, doi101371journalpone0039370, doi1016710272463420020220548domdti20co2, doi104202app20090127, doi105281zenodo5371649, doi105860choice461500, doi105962bhltitle4275, doi105962bhltitle61854"
}

New collecting from the Middle Jurassic beds of the classic Bakonycsernye locality yielded very rich ammonite assemblages from the topmost Aalenian and the Lower Bajocian. A single bed, called here the Ovale Bed gave a high diversity Fissilobiceras ovale Zone fauna, with several stratigraphically diagnostic species and rich representation of early otoitids and stephanoceratids. These latters include topotypes of species described in classic monographs from this place. Here the earliest otoitids and stephanoceratids, Docidoceras wysogorskii and Westermannites chocsinskyi, respectively, appear first in beds belonging into the Graphoceras concavum Zone. The type horizon of W. telegdirothi, the best-known stephanoceratid from Csernye, most probably is within the Hyperlioceras discites Zone. Two new species are described, the otoitid Trilobiticeras (Emileites) kecskemetii n.sp. and the stephanoceratid Mollistephanus ottiliae n.sp., both form the Ovale Bed. Faunal affinities and the early development of the Otoitidae and Stephanoceratidae are discussed.

@article{doi105282ubmepub26932,
    author = "Galácz, András and Dunai, Mihály and Evanics, Zoltán",
    title = "Ammonites from the Lower Bajocian (Middle Jurassic) beds of the classic locality of Bakonycsernye (Transdanubian Hungary), with special regard to the early otoitids and stephanoceratids",
    year = "2015",
    journal = "Open access LMU (Ludwid Maxmilian's Universitat Munchen)",
    abstract = "New collecting from the Middle Jurassic beds of the classic Bakonycsernye locality yielded very rich ammonite assemblages from the topmost Aalenian and the Lower Bajocian. A single bed, called here the Ovale Bed gave a high diversity Fissilobiceras ovale Zone fauna, with several stratigraphically diagnostic species and rich representation of early otoitids and stephanoceratids. These latters include topotypes of species described in classic monographs from this place. Here the earliest otoitids and stephanoceratids, Docidoceras wysogorskii and Westermannites chocsinskyi, respectively, appear first in beds belonging into the Graphoceras concavum Zone. The type horizon of W. telegdirothi, the best-known stephanoceratid from Csernye, most probably is within the Hyperlioceras discites Zone. Two new species are described, the otoitid Trilobiticeras (Emileites) kecskemetii n.sp. and the stephanoceratid Mollistephanus ottiliae n.sp., both form the Ovale Bed. Faunal affinities and the early development of the Otoitidae and Stephanoceratidae are discussed.",
    url = "https://doi.org/10.5282/ubm/epub.26932",
    doi = "10.5282/ubm/epub.26932",
    openalex = "W2275995135"
}

A new dinosaur tracksite in the Vale de Meios quarry (Serra de Aire Formation, Bathonian, Portugal)preserves more than 700 theropod tracks. They are organized in at least 80 unidirectional trackways arranged in a bimodal orientation pattern (W/NW and E/SE). Quantitative and qualitative comparisons reveal that the large tridactyl, elongated and asymmetric tracks resemble the typical Late Jurassic-Early Cretaceous Megalosauripus ichnogenus in all morphometric parameters. Few of the numerous tracks are preserved as elite tracks while the rest are preserved as different gradients of modified true tracks according to water content, erosive factors, radial fractures and internal overtrack formations. Taphonomical determinations are consistent with paleoenvironmental observations that indicate an inter-tidal flat located at the margin of a coastal barrier. The Megalosauripus tracks represent the oldest occurrence of this ichnotaxon and are attributed to large megalosaurid dinosaurs. Their occurrence in Vale de Meios tidal flat represents the unique paleoethological evidence of megalosaurids moving towards the lagoon, most likley during the low tide periods with feeding purposes.

@article{doi101038srep31494,
    author = "Razzolini, Novella L. and Oms, Oriol and Castanera, Diego and Vila, Bernat and dos Santos, Vanda Faria and Galobart, Àngel",
    title = "Ichnological evidence of Megalosaurid Dinosaurs Crossing Middle Jurassic Tidal Flats",
    year = "2016",
    journal = "Scientific Reports",
    abstract = "A new dinosaur tracksite in the Vale de Meios quarry (Serra de Aire Formation, Bathonian, Portugal)preserves more than 700 theropod tracks. They are organized in at least 80 unidirectional trackways arranged in a bimodal orientation pattern (W/NW and E/SE). Quantitative and qualitative comparisons reveal that the large tridactyl, elongated and asymmetric tracks resemble the typical Late Jurassic-Early Cretaceous Megalosauripus ichnogenus in all morphometric parameters. Few of the numerous tracks are preserved as elite tracks while the rest are preserved as different gradients of modified true tracks according to water content, erosive factors, radial fractures and internal overtrack formations. Taphonomical determinations are consistent with paleoenvironmental observations that indicate an inter-tidal flat located at the margin of a coastal barrier. The Megalosauripus tracks represent the oldest occurrence of this ichnotaxon and are attributed to large megalosaurid dinosaurs. Their occurrence in Vale de Meios tidal flat represents the unique paleoethological evidence of megalosaurids moving towards the lagoon, most likley during the low tide periods with feeding purposes.",
    url = "https://doi.org/10.1038/srep31494",
    doi = "10.1038/srep31494",
    openalex = "W2507932685",
    references = "benson2008a, doi1010079789400904095, doi101038261129a0, doi101080147720192011630927, doi1011111475498300277, doi1011270078042120120020, doi101306212f8cba2b2411d78648000102c1865d, doi101306m1357, doi1015468gbdyof, doi105860choice423437, openalexw1533729466, openalexw1594946638"
}

@article{crossref2017jurassic,
    title = "JURASSIC COAST, DORSET, ENGLAND",
    year = "2017",
    journal = "Journal of Coastal Research",
    url = "https://doi.org/10.2112/1551-5036-33.5.ii",
    doi = "10.2112/1551-5036-33.5.ii",
    openalex = "W4252679352",
    pages = "ii-ii",
    volume = "335",
    references = "doi102112jcoastresd15000021, doi102112jcoastresd15002191, doi102112jcoastresd16000351, doi102112jcoastresd1600052, doi102112jcoastresd16001241, doi102112jcoastresd16001391, doi102112jcoastresd16001511, doi102112jcoastresd16001551"
}

Abstract: The supposed base of a slender dermal tail spine from the Inferior Oolite Group (shallow marine deposit, early Middle Jurassic, Aalenian-Bajocian) of Dorset, England, previously reported as “Stegosaurus” and Thyreophora indet., is a half centrum of a caudal vertebra, Archosauria indet. A dorsally and ventrally incomplete vertebra from the same locality has a low centrum that is slightly wider transversely than it is long and, as there is a parapophysis anteriorly, it is part of a cervical vertebra. However, it does not match those of marine reptiles from the Middle Jurassic (Callovian) of England in which the cervical centra are elongate in crocodylomorphs, plate-like in ichthyosaurs, and short and wide in some sauropterygians (plesiosaurs and pliosaurs) but the parapophysis is mid-ventrally situated. The Dorset centrum does not correspond to those of most contemporaneous dinosaurs, viz. theropods, basal sauropodomorphs, basal sauropods and ornithopods. However, it proportions correspond to posterior neck vertebrae of the basal thyreophoran Scelidosaurus (Lower Jurassic, England) and those of eurypod thyreophorans, the dacentrurine stegosaur Dacentrurus (described as Miragaia, Upper Jurassic, Portugal) and the nodosaurid ankylosaur Mymoorapelta (Upper Jurassic, USA), so the Dorset centrum is tentatively identified as Thyreophora indet. The earliest skeletal records for armored dinosaurs are from the Middle Jurassic: for Eurypoda a proximal ulna from the early Bajocian of Scotland, for Stegosauria two large sub-vertically plates from the earliest Bathonian of England, and for Ankylosauria the?Bathonian-Callovian of China or the early middle Callovian of England. However, the stegosaurian footprint taxon Deltapodus brodricki (Aalenian) of England pushes the origin of Stegosauria (and sister group Ankylosauria) down into the Early Jurassic.

@article{doi105281zenodo835532,
    author = "Galton, Peter M.",
    title = {Purported Earliest Bones Of A Plated Dinosaur (Ornithischia: Stegosauria): A "Dermal Tail Spine" And A Centrum From The Aalenian-Bajocian (Middle Jurassic) Of England, With Comments On Other Early Thyreophorans},
    year = "2017",
    journal = "Zenodo (CERN European Organization for Nuclear Research)",
    abstract = "Abstract: The supposed base of a slender dermal tail spine from the Inferior Oolite Group (shallow marine deposit, early Middle Jurassic, Aalenian-Bajocian) of Dorset, England, previously reported as “Stegosaurus” and Thyreophora indet., is a half centrum of a caudal vertebra, Archosauria indet. A dorsally and ventrally incomplete vertebra from the same locality has a low centrum that is slightly wider transversely than it is long and, as there is a parapophysis anteriorly, it is part of a cervical vertebra. However, it does not match those of marine reptiles from the Middle Jurassic (Callovian) of England in which the cervical centra are elongate in crocodylomorphs, plate-like in ichthyosaurs, and short and wide in some sauropterygians (plesiosaurs and pliosaurs) but the parapophysis is mid-ventrally situated. The Dorset centrum does not correspond to those of most contemporaneous dinosaurs, viz. theropods, basal sauropodomorphs, basal sauropods and ornithopods. However, it proportions correspond to posterior neck vertebrae of the basal thyreophoran Scelidosaurus (Lower Jurassic, England) and those of eurypod thyreophorans, the dacentrurine stegosaur Dacentrurus (described as Miragaia, Upper Jurassic, Portugal) and the nodosaurid ankylosaur Mymoorapelta (Upper Jurassic, USA), so the Dorset centrum is tentatively identified as Thyreophora indet. The earliest skeletal records for armored dinosaurs are from the Middle Jurassic: for Eurypoda a proximal ulna from the early Bajocian of Scotland, for Stegosauria two large sub-vertically plates from the earliest Bathonian of England, and for Ankylosauria the?Bathonian-Callovian of China or the early middle Callovian of England. However, the stegosaurian footprint taxon Deltapodus brodricki (Aalenian) of England pushes the origin of Stegosauria (and sister group Ankylosauria) down into the Early Jurassic.",
    url = "https://doi.org/10.5281/zenodo.835532",
    doi = "10.5281/zenodo.835532",
    openalex = "W4298243180"
}

@article{chandler2019two,
    author = "Chandler, Robert B.",
    title = "Two new stephanoceratid ammonites from the Aalenian-Lower Bajocian (Middle Jurassic, Dorset, UK) and their phylogenetic significance",
    year = "2019",
    journal = "Proceedings of the Geologists' Association",
    url = "https://doi.org/10.1016/j.pgeola.2018.05.003",
    doi = "10.1016/j.pgeola.2018.05.003",
    number = "3-4",
    openalex = "W2806454802",
    pages = "307-325",
    volume = "130",
    references = "doi1010079783827431059, doi101016jgeobios201301005, doi101016jpgeola201603007, doi101016jpgeola201704008, doi101016s001678780680043x, doi101144gsjgs14820245, doi101144gsljgs1893049010460, doi1017161tov0i06521, openalexw2221217307, openalexw3215035079"
}

@article{doi101016jpgeola201910004,
    author = "Chandler, Robert B.",
    title = "A new ammonite faunal horizon in the Ovale Zone (Middle Jurassic, Lower Bajocian) and observations on the ammonite genus Sonninia at Coombe Quarry, Mapperton, near Beaminster, Dorset",
    year = "2019",
    journal = "Proceedings of the Geologists Association",
    url = "https://doi.org/10.1016/j.pgeola.2019.10.004",
    doi = "10.1016/j.pgeola.2019.10.004",
    openalex = "W2990780805",
    references = "chandler2019two, doi101016jgeobios201111001, doi101016jpgeola201704008, doi101080147720192013818071, doi101111j00310239200000137x, doi101144gsjgs14820245, doi101144gsljgs1910066010405, doi104202app20080206, doi105282ubmepub26932, doi105962bhltitle61419, openalexw2610807920"
}

In the present paper we describe and discuss belemnite finds from the basal part of the middle Jurassic sequence at the southwest of the Republic of Tatarstan (Tetyushi district). The belemnites were collected from the outcrops located along a shoreline of the Kuybyshevskoye reservoir (Volga river) between the place Tarkhanovskaya pristan’ and the former village Dolinovka. These belemnites indicate that the basal part of the Jurassic sequence is Early Bathonian (Ishmae Zone) or, less probable, Middle Bathonian in age. Such dating triggers a critical review for the age of the middle Jurassic sequence in the region. In particular, poorly preserved ammonites previously collected from the same outcrops higher in the succession and interpreted as members of the Late Bajocian subfamily Garantianinae, are in fact Late Bathonian Gowericeratinae. Consequently, “Beds with Garantiana”—nominally the most ancient ammonite-based biostratigraphic unit within the whole Jurassic of European Russia, based on this assemblage,—is invalid.

@article{doi101134s0869593819060029,
    author = "Ипполитов, А. П. and Gulyaev, D. B.",
    title = "The Age of the pre-Callovian Jurassic Sequence at the Southwest of Tatarstan (Central Russia, Tarkhanovskaya pristan’–Dolinovka reference section) and the Status of the Upper Bajocian “Garantiana-beds”, Previously Described from Here",
    year = "2019",
    journal = "Stratigraphy and Geological Correlation",
    abstract = "In the present paper we describe and discuss belemnite finds from the basal part of the middle Jurassic sequence at the southwest of the Republic of Tatarstan (Tetyushi district). The belemnites were collected from the outcrops located along a shoreline of the Kuybyshevskoye reservoir (Volga river) between the place Tarkhanovskaya pristan’ and the former village Dolinovka. These belemnites indicate that the basal part of the Jurassic sequence is Early Bathonian (Ishmae Zone) or, less probable, Middle Bathonian in age. Such dating triggers a critical review for the age of the middle Jurassic sequence in the region. In particular, poorly preserved ammonites previously collected from the same outcrops higher in the succession and interpreted as members of the Late Bajocian subfamily Garantianinae, are in fact Late Bathonian Gowericeratinae. Consequently, “Beds with Garantiana”—nominally the most ancient ammonite-based biostratigraphic unit within the whole Jurassic of European Russia, based on this assemblage,—is invalid.",
    url = "https://doi.org/10.1134/s0869593819060029",
    doi = "10.1134/s0869593819060029",
    openalex = "W3004127742",
    references = "doi1017161tov0i06521"
}

@article{chandler2021new,
    author = "Chandler, Robert B.",
    title = "New records of rare ammonite species from the Inferior Oolite Formation (Middle Jurassic, Aalenian and Lower Bajocian) of Dorset",
    year = "2021",
    journal = "Proceedings of the Geologists' Association",
    url = "https://doi.org/10.1016/j.pgeola.2021.01.006",
    doi = "10.1016/j.pgeola.2021.01.006",
    number = "3",
    openalex = "W3158086114",
    pages = "316-323",
    volume = "132",
    references = "chandler2019two, doi1010079781461548379, doi101016jgeobios201111001, doi101016jgeobios201301005, doi101016jjseaes200510003, doi101016jpgeola201704008, doi101016jpgeola201910004, doi101038132370a0, doi101127nos31974153, doi101144gsljgs1893049010460, doi1023071786846, openalexw2610807920, openalexw2793832558"
}

Data on fossils and stratigraphy of the Bajocian and Bathonian boundary deposits in the north of European Russia recently published by Ippolitov, Zakharov, Kiselev, et al. are discussed. Their previously proposed correlation of the Middle Jurassic reference sections of the Pechora North region on the Dreshchanka River (a tributary of the Izhma River), as a result of which the visible thickness of deposits is doubled, is critically revised. New finds of the ammonite Arctocephalites arcticus (Newton) confirm the biostratigraphic data previously obtained by Mitta et al. The interval with Mezounio zwerkovi and Retroceramus lungershauseni, previously recognized by Zakharov et al., occurs at the visible base of the Sysola Formation immediately below the interval of finds of Arctocephalites arcticus and most likely should be correlated with the uppermost Bajocian, rather than with the lower Bajocian. Meledina’s proposal to transfer the Borealis, Indistinctus, and Pompeckji zones of the Вoreal scale from the upper Bajocian to the lower Bajocian is considered to be unsubstantiated.

@article{doi101134s0869593821050063,
    author = "Митта, В. В.",
    title = "On the Stratigraphy of the Bajocian–Bathonian Boundary Beds (Middle Jurassic) of the Izhma River Basin, Northern European Russia",
    year = "2021",
    journal = "Stratigraphy and Geological Correlation",
    abstract = "Data on fossils and stratigraphy of the Bajocian and Bathonian boundary deposits in the north of European Russia recently published by Ippolitov, Zakharov, Kiselev, et al. are discussed. Their previously proposed correlation of the Middle Jurassic reference sections of the Pechora North region on the Dreshchanka River (a tributary of the Izhma River), as a result of which the visible thickness of deposits is doubled, is critically revised. New finds of the ammonite Arctocephalites arcticus (Newton) confirm the biostratigraphic data previously obtained by Mitta et al. The interval with Mezounio zwerkovi and Retroceramus lungershauseni, previously recognized by Zakharov et al., occurs at the visible base of the Sysola Formation immediately below the interval of finds of Arctocephalites arcticus and most likely should be correlated with the uppermost Bajocian, rather than with the lower Bajocian. Meledina’s proposal to transfer the Borealis, Indistinctus, and Pompeckji zones of the Вoreal scale from the upper Bajocian to the lower Bajocian is considered to be unsubstantiated.",
    url = "https://doi.org/10.1134/s0869593821050063",
    doi = "10.1134/s0869593821050063",
    openalex = "W3204081915",
    references = "doi1017161tov0i06521"
}

The Bajocian ammonite faunas of the ‘Oberer Blaukalk’ Member (Wedelsandstein Formation) and of the lower part of the ‘Humphriesioolith’ Member (Gosheim Formation) in the vicinity of Gosheim (SW Swabian Alb) are studied. At least three biohorizons of the Sauzei Zone can be distinguished: dilatus, pseudocontrahens, macrum and?carinodiscus biohorizon, probably followed by the deltafalcata biohorizon of the basal Humphriesianum Zone (Pinguis Subzone). This succession is correlated with other sites in SW Germany and abroad.

@article{doi1018476palev15a2,
    author = "Dietze, Volker and Schreiber, Dietmar and Schweigert, Günter",
    title = "The Sauzei-/Humphriesianum zonal boundary (Lower Bajocian, Middle Jurassic) in the type area of the Gosheim Formation (W Swabian Alb, SW Germany)",
    year = "2022",
    journal = "Palaeodiversity",
    abstract = "The Bajocian ammonite faunas of the ‘Oberer Blaukalk’ Member (Wedelsandstein Formation) and of the lower part of the ‘Humphriesioolith’ Member (Gosheim Formation) in the vicinity of Gosheim (SW Swabian Alb) are studied. At least three biohorizons of the Sauzei Zone can be distinguished: dilatus, pseudocontrahens, macrum and?carinodiscus biohorizon, probably followed by the deltafalcata biohorizon of the basal Humphriesianum Zone (Pinguis Subzone). This succession is correlated with other sites in SW Germany and abroad.",
    url = "https://doi.org/10.18476/pale.v15.a2",
    doi = "10.18476/pale.v15.a2",
    openalex = "W4205861192",
    references = "chandler2019two, doi101016jpgeola201704008, doi101017s0016756800149209, doi101144gslmem19950160114, doi105282ubmepub12744, doi105282ubmepub75979, doi105962bhltitle15037, openalexw569655702, openalexw604433666, openalexw612474533"
}

Abstract Current research suggests that the initial radiation of maniraptoran theropods occurred in the Middle Jurassic, although their fossil record is known almost exclusively from the Cretaceous. However, fossils of Jurassic maniraptorans are scarce, usually consisting solely of isolated teeth, and their identifications are often disputed. Here, we apply different machine learning models, in conjunction with morphological comparisons, to a suite of isolated theropod teeth from Bathonian microvertebrate sites in the UK to determine whether any of these can be confidently assigned to Maniraptora. We generated three independent models developed on a training dataset with a wide range of theropod taxa and broad geographical and temporal coverage. Classification of the Middle Jurassic teeth in our sample against these models and comparison of the morphology indicates the presence of at least three distinct dromaeosaur morphotypes, plus a therizinosaur and troodontid in these assemblages. These new referrals significantly extend the ranges of Therizinosauroidea and Troodontidae by some 27 myr. These results indicate that not only were maniraptorans present in the Middle Jurassic, as predicted by previous phylogenetic analyses, but they had already radiated into a diverse fauna that pre‐dated the break‐up of Pangaea. This study also demonstrates the power of machine learning to provide quantitative assessments of isolated teeth in providing a robust, testable framework for taxonomic identifications, and highlights the importance of assessing and including evidence from microvertebrate sites in faunal and evolutionary analyses.

@article{doi101002spp21487,
    author = "Wills, Simon and Underwood, Charlie J. and Barrett, Paul M.",
    title = "Machine learning confirms new records of maniraptoran theropods in Middle Jurassic UK microvertebrate faunas",
    year = "2023",
    journal = "Papers in Palaeontology",
    abstract = "Abstract Current research suggests that the initial radiation of maniraptoran theropods occurred in the Middle Jurassic, although their fossil record is known almost exclusively from the Cretaceous. However, fossils of Jurassic maniraptorans are scarce, usually consisting solely of isolated teeth, and their identifications are often disputed. Here, we apply different machine learning models, in conjunction with morphological comparisons, to a suite of isolated theropod teeth from Bathonian microvertebrate sites in the UK to determine whether any of these can be confidently assigned to Maniraptora. We generated three independent models developed on a training dataset with a wide range of theropod taxa and broad geographical and temporal coverage. Classification of the Middle Jurassic teeth in our sample against these models and comparison of the morphology indicates the presence of at least three distinct dromaeosaur morphotypes, plus a therizinosaur and troodontid in these assemblages. These new referrals significantly extend the ranges of Therizinosauroidea and Troodontidae by some 27 myr. These results indicate that not only were maniraptorans present in the Middle Jurassic, as predicted by previous phylogenetic analyses, but they had already radiated into a diverse fauna that pre‐dated the break‐up of Pangaea. This study also demonstrates the power of machine learning to provide quantitative assessments of isolated teeth in providing a robust, testable framework for taxonomic identifications, and highlights the importance of assessing and including evidence from microvertebrate sites in faunal and evolutionary analyses.",
    url = "https://doi.org/10.1002/spp2.1487",
    doi = "10.1002/spp2.1487",
    openalex = "W4365457719",
    references = "doi1010079783319242774, doi101023a1010933404324, doi101038nmeth2019, doi101111j251761611996tb02073x, doi101146annurevearth081320064052, doi1018637jssv077i01, doi1018901220101, doi105281zenodo16171435, openalexw273955616, openalexw4399271987, woodward1910on"
}

Abstract The cliffs and foreshore at Lyme Regis on the Dorset coast expose a sequence of Early Jurassic marine limestones and mudstones of the Blue Lias Formation and the overlying Charmouth Mudstone Formation, the lowest units of the Hettangian–Aalenian Lias Group. Known for its fossils since at least the mid-seventeenth century, this coastal section became famous in the early nineteenth century for the bones of ‘fossil crocodiles’. Many of the most significant discoveries were made by a family of fossil dealers whose best-known member was Mary Anning (1799–1847). Anning and her family recovered the first scientifically described ichthyosaurs, the first complete plesiosaur and the first British pterosaur to be identified. Anning's finds from Lyme Regis formed the basis of the pioneering palaeoenvironmental reconstruction Duria antiquior. Her geologist friends, some with close personal associations to the town, did much to publicize her discoveries and contribute to both her fame and that of the locality. This famous coastal section, with its important historical associations with a key period in the development of geology and the source of so many significant discoveries in the early nineteenth century, now lies within the Jurassic Coast UNESCO World Heritage Site.

@article{doi101144sp543202342,
    author = "Sharpe, Tom",
    title = "The Early Jurassic sequence of Lyme Regis, Dorset, England and its place in the history of geology and palaeontology",
    year = "2023",
    journal = "Geological Society London Special Publications",
    abstract = "Abstract The cliffs and foreshore at Lyme Regis on the Dorset coast expose a sequence of Early Jurassic marine limestones and mudstones of the Blue Lias Formation and the overlying Charmouth Mudstone Formation, the lowest units of the Hettangian–Aalenian Lias Group. Known for its fossils since at least the mid-seventeenth century, this coastal section became famous in the early nineteenth century for the bones of ‘fossil crocodiles’. Many of the most significant discoveries were made by a family of fossil dealers whose best-known member was Mary Anning (1799–1847). Anning and her family recovered the first scientifically described ichthyosaurs, the first complete plesiosaur and the first British pterosaur to be identified. Anning's finds from Lyme Regis formed the basis of the pioneering palaeoenvironmental reconstruction Duria antiquior. Her geologist friends, some with close personal associations to the town, did much to publicize her discoveries and contribute to both her fame and that of the locality. This famous coastal section, with its important historical associations with a key period in the development of geology and the source of so many significant discoveries in the early nineteenth century, now lies within the Jurassic Coast UNESCO World Heritage Site.",
    url = "https://doi.org/10.1144/sp543-2023-42",
    doi = "10.1144/sp543-2023-42",
    openalex = "W4388659781",
    references = "doi101016jpgeola201905005"
}

@article{whicher2023lytoceratid,
    author = "Whicher, John T. and Chandler, Robert B. and Hoffmann, René",
    title = "Lytoceratid ammonites from the Inferior Oolite Formation (Middle Jurassic, Aalenian and Bajocian) of Dorset (United Kingdom)",
    year = "2023",
    journal = "Proceedings of the Geologists' Association",
    url = "https://doi.org/10.1016/j.pgeola.2023.03.001",
    doi = "10.1016/j.pgeola.2023.03.001",
    number = "2",
    openalex = "W4327718569",
    pages = "216-245",
    volume = "134",
    references = "chandler2021new, doi101002mmng200900008, doi1010079789401796309, doi10100797894017963099, doi101016jpgeola201910004, doi101016s001678780880257x, doi101038ncomms10015, doi101093jheredesu033, doi101126scienceaao4593, doi101146annurevgenet120417031404, doi1018476palev14a3, doi1034194geusbv14648"
}

The Inferior Oolite Formation of Dorset includes Lower Bajocian strata often rich in stephanoceratid ammonites comparable with assemblages from the rocks of the Transdanubian Central Range (W Hungary) that are the subject of research by András Galácz, specifically Lokuticeras. In Dorset the stratigraphical occurrence of the ‘Lokuticeras morphology’ can be traced over a range of strata from the Sauzei and Humphriesianum zones and the assemblage composition of the biohorizons in which they occur identified. Lokuticeras is most abundant in Dorset in the uppermost Humphriesianum and Blagdeni subzones of the Humphriesianum Zone. Specimens from three Dorset locations are figured facilitating comparison with the Hungarian specimens. Type species Lokuticeras rossbrunnense is common at the Humphriesianum–Blagdeni subzonal transition. A new biohorizon is erected Lokuticeras rossbrunnense nov. as the lowest biohorizon of the Blagdeni Subzone facilitating correlating some areas of Europe. A critical review is made of previously published specimens and their affinities

@article{doi1023928foldtkozl20241542177,
    author = "Chandler, Robert M.",
    title = "Bajocian stephanoceratid ammonites and their stratigraphy from Dorset, UK with reference to the work of András GALÁCZ",
    year = "2024",
    journal = "Földtani Közlöny",
    abstract = "The Inferior Oolite Formation of Dorset includes Lower Bajocian strata often rich in stephanoceratid ammonites comparable with assemblages from the rocks of the Transdanubian Central Range (W Hungary) that are the subject of research by András Galácz, specifically Lokuticeras. In Dorset the stratigraphical occurrence of the ‘Lokuticeras morphology’ can be traced over a range of strata from the Sauzei and Humphriesianum zones and the assemblage composition of the biohorizons in which they occur identified. Lokuticeras is most abundant in Dorset in the uppermost Humphriesianum and Blagdeni subzones of the Humphriesianum Zone. Specimens from three Dorset locations are figured facilitating comparison with the Hungarian specimens. Type species Lokuticeras rossbrunnense is common at the Humphriesianum–Blagdeni subzonal transition. A new biohorizon is erected Lokuticeras rossbrunnense nov. as the lowest biohorizon of the Blagdeni Subzone facilitating correlating some areas of Europe. A critical review is made of previously published specimens and their affinities",
    url = "https://doi.org/10.23928/foldt.kozl.2024.154.2.177",
    doi = "10.23928/foldt.kozl.2024.154.2.177",
    openalex = "W4401645202",
    references = "chandler2019two, doi101016jgeobios201301005, doi101016jpgeola201603007, doi101016jpgeola201704008, doi101016jpgeola202303004, doi101016s0016699594801223, doi101016s0016787885800341, doi1011270077774920140429, doi101127njgpa20160615, doi101144gslmem19950160114"
}

Abstract The Lower Bajocian/Upper Bajocian transition was analysed in the Casa Chimeneas section (JRi3), Sierra de Ricote (Murcia), which is located in the Median Subbetic paleogeographic domain. This stratigraphic section, consisting of an alternation of marls and marly limestones with radiolarians, finely shelled bivalves, Zoophycos and frequent ammonites, represents the best stratigraphic sequence of the Subbetic (Betic Range) and, also possibly, of the Mediterranean province (westernmost Tethyan Realm) to carry out this analysis. Ammonite have been sampled since the 90s increasing the collection available, which, together with the analysis of calcareous nannofossil assemblages and the carbon-isotope δ 13 C curve, allows accurately modify the position of the Lower Bajocian/Upper Bajocian boundary in this stratigraphic reference section. Ammonite assemblages are dominated by Oppeliinae, Phylloceratoidea and Sphaeroceratidae, but other taxa with more biostratigraphical value (Stephanoceratinae, Cadomitinae, Frebolditinae, Leptosphinctinae and Parkinsoniidae) are also common. The absence of the typical Teloceras and the scarcity of Caumonstisphinctes make difficult to recognize the base of the Upper Bajocian. The appearance of the species Leptosphinctes constrictus, the last records of the genus Paviceras, and the species Masckeites? aff. exilis and Subcollina ochoterenai are the most significant bioevents marking this boundary. The first specimens, but not first occurrences, which would be recorded below the oldest studied sample, of the calcareous nannofossils Cyclagelosphaera margerelii and Crepidolithus crassus are identified in the base of the Blagdeni Subzone, and those of Discorhabdus ignotus and Ethmorhabdus gallicus within the upper part of the same subzone. The last occurrences (LOs) of Hexalithus magharensis and Carinolithus superbus are located within the Niortense Zone. Significant fluctuations are recorded in the δ 13 C curve in the Lower Bajocian/Upper Bajocian transition coinciding with the turnover of ammonites and the increase in diversity of calcareous nannofossils. Some ammonite taxa with significant biostratigraphic value are herein described and illustrated for the first time in Sierra de Ricote.

@article{doi101007s4151302500277x,
    author = "Sandoval, José and Aguado, Roque and Fraguas, Ángela and Dogherty, Luis O.",
    title = "The lower/upper Bajocian boundary (Middle Jurassic) in the Casa Chimeneas section: Sierra de Ricote (Murcia Region), southern Spain",
    year = "2025",
    journal = "Journal of Iberian Geology",
    abstract = "Abstract The Lower Bajocian/Upper Bajocian transition was analysed in the Casa Chimeneas section (JRi3), Sierra de Ricote (Murcia), which is located in the Median Subbetic paleogeographic domain. This stratigraphic section, consisting of an alternation of marls and marly limestones with radiolarians, finely shelled bivalves, Zoophycos and frequent ammonites, represents the best stratigraphic sequence of the Subbetic (Betic Range) and, also possibly, of the Mediterranean province (westernmost Tethyan Realm) to carry out this analysis. Ammonite have been sampled since the 90s increasing the collection available, which, together with the analysis of calcareous nannofossil assemblages and the carbon-isotope δ 13 C curve, allows accurately modify the position of the Lower Bajocian/Upper Bajocian boundary in this stratigraphic reference section. Ammonite assemblages are dominated by Oppeliinae, Phylloceratoidea and Sphaeroceratidae, but other taxa with more biostratigraphical value (Stephanoceratinae, Cadomitinae, Frebolditinae, Leptosphinctinae and Parkinsoniidae) are also common. The absence of the typical Teloceras and the scarcity of Caumonstisphinctes make difficult to recognize the base of the Upper Bajocian. The appearance of the species Leptosphinctes constrictus, the last records of the genus Paviceras, and the species Masckeites? aff. exilis and Subcollina ochoterenai are the most significant bioevents marking this boundary. The first specimens, but not first occurrences, which would be recorded below the oldest studied sample, of the calcareous nannofossils Cyclagelosphaera margerelii and Crepidolithus crassus are identified in the base of the Blagdeni Subzone, and those of Discorhabdus ignotus and Ethmorhabdus gallicus within the upper part of the same subzone. The last occurrences (LOs) of Hexalithus magharensis and Carinolithus superbus are located within the Niortense Zone. Significant fluctuations are recorded in the δ 13 C curve in the Lower Bajocian/Upper Bajocian transition coinciding with the turnover of ammonites and the increase in diversity of calcareous nannofossils. Some ammonite taxa with significant biostratigraphic value are herein described and illustrated for the first time in Sierra de Ricote.",
    url = "https://doi.org/10.1007/s41513-025-00277-x",
    doi = "10.1007/s41513-025-00277-x",
    openalex = "W4408154229",
    references = "doi101016jpgeola201704008"
}