Histology

This book, each chapter of which has been prepared by one or more recognized authorities, includes the best of most of the research that has been done in the field of biochemistry and physiology of bone during the past 25 years. Twenty-eight scientists have participated in writing it. The editor is widely known for his interest in this subject and has succeeded in producing a well-ordered arrangement of the material. There is an extensive bibliography and an author index as well as a subject index. This is a reference book rather than a textbook, and it should be of great value to every student or teacher who is interested in a better understanding of bone in health and disease.

@article{doi101001jama195602970180082039,
    author = "Brash, J. C.",
    title = "The Biochemistry and Physiology of Bone",
    year = "1956",
    journal = "Journal of the American Medical Association",
    abstract = "This book, each chapter of which has been prepared by one or more recognized authorities, includes the best of most of the research that has been done in the field of biochemistry and physiology of bone during the past 25 years. Twenty-eight scientists have participated in writing it. The editor is widely known for his interest in this subject and has succeeded in producing a well-ordered arrangement of the material. There is an extensive bibliography and an author index as well as a subject index. This is a reference book rather than a textbook, and it should be of great value to every student or teacher who is interested in a better understanding of bone in health and disease.",
    url = "https://doi.org/10.1001/jama.1956.02970180082039",
    doi = "10.1001/jama.1956.02970180082039",
    openalex = "W1532749597"
}

@article{rozhdestvensky1965growth3,
    author = "Rozhdestvensky, A. K",
    title = "Growth changes in Asian dinosaurs and some problems of their taxonomy",
    year = "1965",
    journal = "Palaeontological Journal, p. 95-109",
    note = "talkorigins\_source = {true}; raw\_reference = {Rozhdestvensky, A. K., 1965, Growth changes in Asian dinosaurs and some problems of their taxonomy: Palaeontological Journal, p. 95-109.}"
}

@incollection{ricqles1980tissue2,
    author = "Ricqles, A. R",
    editor = "Thomas, D. K. and Olson, E. C.",
    title = "Tissue Structures of Dinosaur Bones: Functional Significance and Possible Relation to Dinosaur Physiology",
    year = "1980",
    booktitle = "A Cold Look at the Warm Blooded Dinosaurs",
    publisher = "Washington, D.C., American Association for the Advancement of Science, p. 103-140",
    note = "talkorigins\_source = {true}; raw\_reference = {Ricqles, A. R., 1980, Tissue Structures of Dinosaur Bones: Functional Significance and Possible Relation to Dinosaur Physiology, in Thomas, D. K., and Olson, E. C., eds., A Cold Look at the Warm Blooded Dinosaurs: Washington, D.C., American Association for the Advancement of Science, p. 103-140.}"
}

@inproceedings{reid1984the1,
    author = "Reid, R. E. H",
    title = "The histology of dinosaurian bone, and its possible bearing on dinosaur physiology",
    year = "1984",
    booktitle = "Symposium of the Zoological Society, London, v. 52, p. 629-663",
    note = "talkorigins\_source = {true}; raw\_reference = {Reid, R. E. H., 1984, The histology of dinosaurian bone, and its possible bearing on dinosaur physiology: Symposium of the Zoological Society, London, v. 52, p. 629-663.}"
}

The mid‐shaft circumferences of the humerus and femur are closely related to body weight in living terrestrial vertebrates. Because these elements are frequently preserved in subfossil and fossil vertebrate skeletal materials, the relationship can be used to estimate body weight in extinct vertebrates. When the allometric equations are applied to the mid‐shaft circumferences of these elements in dinosaurs, the weights calculated for some giant sauropods (Brachiosaurus) are found to be lighter than previous estimates.

@article{doi101111j146979981985tb04915x,
    author = "Anderson, John F. and Hall-Martin, A.J. and Russell, Dale A.",
    title = "Long‐bone circumference and weight in mammals, birds and dinosaurs",
    year = "1985",
    journal = "Journal of Zoology",
    abstract = "The mid‐shaft circumferences of the humerus and femur are closely related to body weight in living terrestrial vertebrates. Because these elements are frequently preserved in subfossil and fossil vertebrate skeletal materials, the relationship can be used to estimate body weight in extinct vertebrates. When the allometric equations are applied to the mid‐shaft circumferences of these elements in dinosaurs, the weights calculated for some giant sauropods (Brachiosaurus) are found to be lighter than previous estimates.",
    url = "https://doi.org/10.1111/j.1469-7998.1985.tb04915.x",
    doi = "10.1111/j.1469-7998.1985.tb04915.x",
    openalex = "W2160621949",
    references = "bakker1972anatomical, crossref1976allosaurus, doi101017s0094837300004322, doi101038238081a0, doi101086410790, doi101111j136520281979tb00256x, doi101111j146979981979tb03940x, doi101111j146979981979tb03964x, doi101111j146979981983tb05785x, doi1023072987996, openalexw654491377"
}

Two bone beds, Canyon Bone Bed and Dino Ridge Quarry, have yielded the near-exclusive remains of a new species of Styracosaurus (Family Ceratopsidae); the third bone bed, Westside Quarry, is dominated by a new species of Prosaurolophus (Family Hadrosauridae). Evidence supporting a drought hypothesis includes: 1) a seasonal, semiarid paleoclimate, 2) associated caliche horizons, 3) aqueous depositional settings, 4) apparent age distributions characteristic of modern drought mortality (CBB and DRQ), and 5) the intraformational recurrence of low-diversity bone beds. Several alternative scenarios were considered, but drought proved most reasonable in light of the enhanced probability of preserving drought assemblages, and the species-selective and recurrent nature of modern drought mortality

@article{doi1023073514834,
    author = "Rogers, Raymond R.",
    title = "Taphonomy of Three Dinosaur Bone Beds in the Upper Cretaceous Two Medicine Formation of Northwestern Montana: Evidence for Drought-Related Mortality",
    year = "1990",
    journal = "Palaios",
    abstract = "Two bone beds, Canyon Bone Bed and Dino Ridge Quarry, have yielded the near-exclusive remains of a new species of Styracosaurus (Family Ceratopsidae); the third bone bed, Westside Quarry, is dominated by a new species of Prosaurolophus (Family Hadrosauridae). Evidence supporting a drought hypothesis includes: 1) a seasonal, semiarid paleoclimate, 2) associated caliche horizons, 3) aqueous depositional settings, 4) apparent age distributions characteristic of modern drought mortality (CBB and DRQ), and 5) the intraformational recurrence of low-diversity bone beds. Several alternative scenarios were considered, but drought proved most reasonable in light of the enhanced probability of preserving drought assemblages, and the species-selective and recurrent nature of modern drought mortality",
    url = "https://doi.org/10.2307/3514834",
    doi = "10.2307/3514834",
    openalex = "W2042788701",
    references = "doi101016s0195667105800308"
}

ABSTRACT The bone microstructure of three third metatarsals and two tibiae of differing sizes from Troodon formosus was examined. Bone in T. formosus passed through three ontogenetic stages: rapid fibro-lamellar, moderate lamellar-zonal, and slow avascular lamellar growth. Highly-vascularized fibro-lamellar bone accounted for the majority of growth, with adult size possibly being reached in 3 to 5 years. No significant growth occurred after T. formosus reached a body weight of roughly 50 kg (femur: tibia length 310:425 mm). Abundant vasculature together with dense Haversian bone suggests T. formosus had a relatively high metabolism. Other gross morphological features (large brain, large eyes, cursorial adaptations including high tibia: femur ratio) would indicate T. formosus was very active and possibly endothermic.

@article{doi10108002724634199310011490,
    author = "Varricchio, David J.",
    title = "Bone microstructure of the Upper Cretaceous theropod dinosaur Troodon formosus",
    year = "1993",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT The bone microstructure of three third metatarsals and two tibiae of differing sizes from Troodon formosus was examined. Bone in T. formosus passed through three ontogenetic stages: rapid fibro-lamellar, moderate lamellar-zonal, and slow avascular lamellar growth. Highly-vascularized fibro-lamellar bone accounted for the majority of growth, with adult size possibly being reached in 3 to 5 years. No significant growth occurred after T. formosus reached a body weight of roughly 50 kg (femur: tibia length 310:425 mm). Abundant vasculature together with dense Haversian bone suggests T. formosus had a relatively high metabolism. Other gross morphological features (large brain, large eyes, cursorial adaptations including high tibia: femur ratio) would indicate T. formosus was very active and possibly endothermic.",
    url = "https://doi.org/10.1080/02724634.1993.10011490",
    doi = "10.1080/02724634.1993.10011490",
    openalex = "W1993549596",
    references = "bouvier1977dinosaur, crossref1976allosaurus, doi1010160031018271900447, doi101038332256a0, doi101086410790, doi101111j146979981985tb04915x, doi1023071443592, doi1023073514834, openalexw575222456, russell1969a, spotila1973a, wilson1985stenonychosaurus"
}

Histological and ultrastructural evaluation of the ends of long bones of juvenile dinosaurs from the Upper Cretaceous Two Medicine Formation of Montana revealed the preservation of growth plates. Growth plates are discs of cartilage present near the ends of growing long bones that generate bone elongation. Comparison of the fossils with modern taxa demonstrated homology of the growth plate in birds and dinosaurs. The presence of an avian-type growth plate in dinosaurs adds a shared derived anatomical character corroborating inclusion of birds within the Dinosauria. Additionally, possession of a growth plate, which in birds is capable of producing rapid determinate long bone growth, implies that an avian developmental pattern may have been present in these dinosaurs.

@article{doi101126science26251422020,
    author = "Barreto, Claudia and Albrecht, Ralph M. and Bjorling, Dale E. and Horner, John R. and Wilsman, Norman J.",
    title = "Evidence of the Growth Plate and the Growth of Long Bones in Juvenile Dinosaurs",
    year = "1993",
    journal = "Science",
    abstract = "Histological and ultrastructural evaluation of the ends of long bones of juvenile dinosaurs from the Upper Cretaceous Two Medicine Formation of Montana revealed the preservation of growth plates. Growth plates are discs of cartilage present near the ends of growing long bones that generate bone elongation. Comparison of the fossils with modern taxa demonstrated homology of the growth plate in birds and dinosaurs. The presence of an avian-type growth plate in dinosaurs adds a shared derived anatomical character corroborating inclusion of birds within the Dinosauria. Additionally, possession of a growth plate, which in birds is capable of producing rapid determinate long bone growth, implies that an avian developmental pattern may have been present in these dinosaurs.",
    url = "https://doi.org/10.1126/science.262.5142.2020",
    doi = "10.1126/science.262.5142.2020",
    openalex = "W2007794110",
    references = "bouvier1977dinosaur, doi101002jor1100090306, doi101017s247526300000091x, doi101038248168a0, doi101038282296a0, doi101038297675a0, doi101038361064a0, doi1010970124139819921100000022, doi1021060000462319876902000002, doi1023071443592, openalexw575222456"
}

The bone histology of humeri of a number of taxonomically well established and easily definable dicynodont genera is described and compared. The bone of Aulacephalodon, Cistecephalus, Dicynodon, Endothiodon, Lystrosaurus, Kannemeyeria and Oudenodon consists of alternating fibro-lamellar and lamellated bone tissue, while that of Diictodon consists only of fibro-lamellar tissue. The presence of fibro-lamellar bone in all the genera studied, indicates that the bone was deposited rapidly, but the occurrence of lamellated bone tissue suggests that all the genera except Diictodon, also had intermittent periods of slow growth. This is the first time that a comparative study of bone histology of different dicynodont genera has been attempted by using one particular bone element to standardise intergeneric comparisons.

@article{openalexw406909995,
    author = "Chinsamy, Anusuya and Rubidge, Bruce S.",
    title = "Dicynodont (Therapsida) bone histology: phylogenetic and physiological implications",
    year = "1993",
    journal = "University of the Witwatersrand, Johannesburg Institutional Repository on DSpace (University of the Witwatersrand, Johannesburg)",
    abstract = "The bone histology of humeri of a number of taxonomically well established and easily definable dicynodont genera is described and compared. The bone of Aulacephalodon, Cistecephalus, Dicynodon, Endothiodon, Lystrosaurus, Kannemeyeria and Oudenodon consists of alternating fibro-lamellar and lamellated bone tissue, while that of Diictodon consists only of fibro-lamellar tissue. The presence of fibro-lamellar bone in all the genera studied, indicates that the bone was deposited rapidly, but the occurrence of lamellated bone tissue suggests that all the genera except Diictodon, also had intermittent periods of slow growth. This is the first time that a comparative study of bone histology of different dicynodont genera has been attempted by using one particular bone element to standardise intergeneric comparisons.",
    openalex = "W406909995",
    references = "doi101007bf02118752, doi1010160031018287900307, doi101098rstb19810001, doi101163156853891x00356, doi1023071444994, doi104102koedoev34i1409, doi105281zenodo16241384, openalexw2235073057, openalexw2259112626, openalexw63405278"
}

A study of the anatomy and morphology of a fossil skeleton indicates the overall size, posture, and form of the animal. Even various functional aspects of the skeleton such as preferred mode of locomotion and chewing mechanisms can be deduced from such studies. But the desire to understand dinosaurs as dynamic, once-living animals and not merely as taxonomic entities arranged in phylogenetic schemes, goes beyond this. In 1842, Sir Richard Owen not only presented dinosaurs taxonomically but he also initiated the quest to understand the biology of these animals. In recent decades, the study of dinosaur paleobiology has blossomed, and has provided a crucial link between studies of morphology (structures) and that of function and physiology.

@article{chinsamy1994dinosaur,
    author = "Chinsamy, Anusuya",
    title = "Dinosaur Bone Histology: Implications and Inferences",
    year = "1994",
    journal = "The Paleontological Society Special Publications",
    abstract = "A study of the anatomy and morphology of a fossil skeleton indicates the overall size, posture, and form of the animal. Even various functional aspects of the skeleton such as preferred mode of locomotion and chewing mechanisms can be deduced from such studies. But the desire to understand dinosaurs as dynamic, once-living animals and not merely as taxonomic entities arranged in phylogenetic schemes, goes beyond this. In 1842, Sir Richard Owen not only presented dinosaurs taxonomically but he also initiated the quest to understand the biology of these animals. In recent decades, the study of dinosaur paleobiology has blossomed, and has provided a crucial link between studies of morphology (structures) and that of function and physiology.",
    url = "https://doi.org/10.1017/s2475262200009539",
    doi = "10.1017/s2475262200009539",
    openalex = "W3169749473",
    pages = "213-228",
    volume = "7",
    references = "doi101007bf02118752, doi10108002724634199310011490, doi101093clinids222240, doi101126science26251422020, doi101139z79216, doi1023071443592, openalexw1607828269, openalexw406909995, openalexw575222456, openalexw991367939"
}

ABSTRACT Histological changes through ontogeny in Dryosaurus lettowvorbecki are reported. Thin sections of femora are examined using light microscopy (ordinary and polarized light). The results suggests that Dryosaurus grew rapidly throughout ontogeny without any pauses in its bone deposition rate. This pattern differs uniquely from the histological descriptions of prior studies of growth series of other dinosaur taxa. This study provides support to the hypothesis that dinosaurs probably exhibited a range of physiologies and growth patterns.

@article{doi10108002724634199510011209,
    author = "Chinsamy, Anusuya",
    title = "Ontogenetic Changes in the Bone Histology of the Late Jurassic Ornithopod Dryosaurus lettowvorbecki",
    year = "1995",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Histological changes through ontogeny in Dryosaurus lettowvorbecki are reported. Thin sections of femora are examined using light microscopy (ordinary and polarized light). The results suggests that Dryosaurus grew rapidly throughout ontogeny without any pauses in its bone deposition rate. This pattern differs uniquely from the histological descriptions of prior studies of growth series of other dinosaur taxa. This study provides support to the hypothesis that dinosaurs probably exhibited a range of physiologies and growth patterns.",
    url = "https://doi.org/10.1080/02724634.1995.10011209",
    doi = "10.1080/02724634.1995.10011209",
    openalex = "W2094384037",
    references = "bouvier1977dinosaur, openalexw406909995"
}

@article{doi101016s0031018296001125,
    author = "Kolodny, Yehoshua and Luz, Boaz and Sander, Martin and Clemens, W. A.",
    title = "Dinosaur bones: fossils or pseudomorphs? The pitfalls of physiology reconstruction from apatitic fossils",
    year = "1996",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/s0031-0182(96)00112-5",
    doi = "10.1016/s0031-0182(96)00112-5",
    openalex = "W1992962409",
    references = "brouwers1987dinosaurs, davies1987duckbill, doi1010160012821x83901000, doi101016001670378490259x, doi1010160016703784903387, doi1010160016703795002504, doi1010160022519366901858, doi1010160168962290900092, doi101111j215334901964tb00181x, doi10113000167606195162417cits20co2, doi1011300091761319930210503pioatv23co2, doi102973dsdpproc291171975, lehman1987late, openalexw584691296"
}

ABSTRACT The histological study of various bones in the families Teleosauridae and Metriorhynchidae reveals common, but also contrasting structural features of the skeleton. Both display a zonal pattern of bone tissue, suggesting a cyclic growth and an ecto-poikilothermic physiology, quite similar to those of recent crocodiles. However, the Teleosauridae exhibit no peculiar skeletal specializations related to marine life, which suggests that they had an amphibious, rather than a truly marine habitat. Conversely, the skeleton of the Metriorhynchidae displays a certain degree of structural lightening, especially obvious in their skull, but also present in their femora and ribs. This structural specialization of the skeleton, together with the supposed physiological regime of the Metriorhynchidae, had definite bearings on their body trim in water, locomotor capabilities, and activity cycles. These various topics are discussed with reference to the ecological and eco-physiological adaptations of the Thalattosuchia.

@article{doi10108002724634199610011359,
    author = "Hua, Stéphane and de Buffrénil, Vivian",
    title = "Bone histology as a clue in the interpretation of functional adaptations in the Thalattosuchia (Reptilia, Crocodylia)",
    year = "1996",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT The histological study of various bones in the families Teleosauridae and Metriorhynchidae reveals common, but also contrasting structural features of the skeleton. Both display a zonal pattern of bone tissue, suggesting a cyclic growth and an ecto-poikilothermic physiology, quite similar to those of recent crocodiles. However, the Teleosauridae exhibit no peculiar skeletal specializations related to marine life, which suggests that they had an amphibious, rather than a truly marine habitat. Conversely, the skeleton of the Metriorhynchidae displays a certain degree of structural lightening, especially obvious in their skull, but also present in their femora and ribs. This structural specialization of the skeleton, together with the supposed physiological regime of the Metriorhynchidae, had definite bearings on their body trim in water, locomotor capabilities, and activity cycles. These various topics are discussed with reference to the ecological and eco-physiological adaptations of the Thalattosuchia.",
    url = "https://doi.org/10.1080/02724634.1996.10011359",
    doi = "10.1080/02724634.1996.10011359",
    openalex = "W2094653223",
    references = "doi101007bf02118752, doi101139z79216, openalexw1959044725"
}

@article{chinsamy1998polar,
    author = "Chinsamy, Anusuya and Rich, T. and Vickers-Rich, P.",
    title = "Polar dinosaur bone histology",
    year = "1998",
    journal = "Journal of Vertebrate Paleontology",
    url = "https://doi.org/10.1080/02724634.1998.10011066",
    doi = "10.1080/02724634.1998.10011066",
    number = "2",
    openalex = "W2095513015",
    pages = "385-390",
    volume = "18",
    references = "brouwers1987dinosaurs, doi101007bf02988144, doi1010160012821x89900186, doi10108002724634199410011538, doi101093clinids222240, doi101126science2645160828, doi101146annurevph57030195000441, doi1023071443592, openalexw2603335639, openalexw575222456"
}

Twelve different bones from the skeleton of the holotype specimen of the hadrosaurian dinosaur Hypacrosaurus stebingeri were thin-sectioned to evaluate the significance of lines of arrested growth (LAGs) in age assessments. The presence of an external fundamental system (EFS) at the external surface of the cortex and mature epiphyses indicate that the Hypacrosaurus specimen had reached adulthood and growth had slowed considerably from earlier stages. The number of LAGs varied from none in the pedal phalanx to as many as eight in the tibia and femur. Most elements had experienced considerable Haversian reconstruction that had most likely obliterated many LAGs. The tibia was found to have experienced the least amount of reconstruction, but was still not optimal for skeletochronology because the LAGs were difficult to count near the periosteal surface. Additionally, the numbers of LAGs within the EFS vary considerably around the circumference of a single element and among elements. Counting LAGs from a single bone to assess skeletochronology appears to be unreliable, particularly when a fundamental system exists. Because LAGs are plesiomorphic for tetrapods, and because they are present in over a dozen orders of mammals, they have no particular physiological meaning that can be generalized to particular amniote groups without independent physiological evidence. Descriptions of dinosaur physiology as “intermediate” between the physiology of living reptiles and that of living birds and mammals may or may not be valid, but cannot be based reliably on the presence of LAGs.

@article{doi101017s0094837300021308,
    author = "Horner, John R. and de Ricqlès, Armand and Padian, Kevin",
    title = "Variation in dinosaur skeletochronology indicators: implications for age assessment and physiology",
    year = "1999",
    journal = "Paleobiology",
    abstract = "Twelve different bones from the skeleton of the holotype specimen of the hadrosaurian dinosaur Hypacrosaurus stebingeri were thin-sectioned to evaluate the significance of lines of arrested growth (LAGs) in age assessments. The presence of an external fundamental system (EFS) at the external surface of the cortex and mature epiphyses indicate that the Hypacrosaurus specimen had reached adulthood and growth had slowed considerably from earlier stages. The number of LAGs varied from none in the pedal phalanx to as many as eight in the tibia and femur. Most elements had experienced considerable Haversian reconstruction that had most likely obliterated many LAGs. The tibia was found to have experienced the least amount of reconstruction, but was still not optimal for skeletochronology because the LAGs were difficult to count near the periosteal surface. Additionally, the numbers of LAGs within the EFS vary considerably around the circumference of a single element and among elements. Counting LAGs from a single bone to assess skeletochronology appears to be unreliable, particularly when a fundamental system exists. Because LAGs are plesiomorphic for tetrapods, and because they are present in over a dozen orders of mammals, they have no particular physiological meaning that can be generalized to particular amniote groups without independent physiological evidence. Descriptions of dinosaur physiology as “intermediate” between the physiology of living reptiles and that of living birds and mammals may or may not be valid, but cannot be based reliably on the presence of LAGs.",
    url = "https://doi.org/10.1017/s0094837300021308",
    doi = "10.1017/s0094837300021308",
    openalex = "W2285964556",
    references = "chinsamy1994dinosaur, chinsamy1998polar, crossref1998encyclopedia, doi101002jmor1051080103, doi101017s0094837300013543, doi10108002724634199310011490, doi10108002724634199510011271, doi101093clinids222240, doi101111j109636422000tb00016x, doi101111j155856461974tb00777x, doi1016710272463420000200115lbhoth20co2, doi1023071564284, doi105860choice353642, openalexw424753225, openalexw575222456, openalexw597127060, openalexw648632191, openalexw991367939"
}

The skeleton undergoes substantial histological modification during ontogeny in association with longitudinal growth, shape changes, reproductive activity, and fatigue repair. This variation can hinder attempts to reconstruct life history attributes for individuals, particularly when only fossil materials are availble for study. Histological examinations of multiple elements throughout development provide a means to control for such variability and facilitate accurate life history assessments. In the present study, the microstructure of various major long bones of the ceratopsian Psittacosaurus monogoliensis Osborn were examined from a growth series spanning juvenile through adult developmental stages. The first reconstruction of a growth curve (mass vs. age) for a dinosaur was made for this taxon using a new method called Developmental Mass Extrapolation. The results suggest P. mongoliensis: (1) had an S-shaped growth curve characteristics of most extant vertebrates, and (2) had maximal growth rates that exceeded extant reptiles and marsupials, but were slower than most avian and eutherian taxa.

@article{doi101111j109636422000tb02201x,
    author = "Erickson, Gregory M. and TUMANOVA, TATYANA A.",
    title = "Growth curve of Psittacosaurus mongoliensis Osborn (Ceratopsia: Psittacosauridae) inferred from long bone histology",
    year = "2000",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "The skeleton undergoes substantial histological modification during ontogeny in association with longitudinal growth, shape changes, reproductive activity, and fatigue repair. This variation can hinder attempts to reconstruct life history attributes for individuals, particularly when only fossil materials are availble for study. Histological examinations of multiple elements throughout development provide a means to control for such variability and facilitate accurate life history assessments. In the present study, the microstructure of various major long bones of the ceratopsian Psittacosaurus monogoliensis Osborn were examined from a growth series spanning juvenile through adult developmental stages. The first reconstruction of a growth curve (mass vs. age) for a dinosaur was made for this taxon using a new method called Developmental Mass Extrapolation. The results suggest P. mongoliensis: (1) had an S-shaped growth curve characteristics of most extant vertebrates, and (2) had maximal growth rates that exceeded extant reptiles and marsupials, but were slower than most avian and eutherian taxa.",
    url = "https://doi.org/10.1111/j.1096-3642.2000.tb02201.x",
    doi = "10.1111/j.1096-3642.2000.tb02201.x",
    openalex = "W2044005382",
    references = "chinsamy1994dinosaur, crossref1859supplement, crossref1998encyclopedia, doi1010160021929085902040, doi101017cbo9780511608551, doi101029sc005p0175, doi101073pnas932514623, doi101086401873, doi101086410622, doi101111j146979981975tb01405x, doi101126science26251422020, doi101139z79216, doi1021060000462319796104000008, doi105860choice353642, openalexw1497041718, openalexw1558456135, openalexw2226673225, openalexw3215057009, openalexw991367939, vonbertalanffy1957quantitative"
}

ABSTRACT Ontogenetic changes in the bone histology of Maiasaura peeblesorum are revealed by six relatively distinct but gradational growth stages: early and late nestling, early and late juvenile, sub-adult, and adult. These stages are distinguished not only by relative size but by changes in the histological patterns of bones at each stage. In general, the earliest stages are marked by spongy bone matrix with large vascular canals. Through growth, the cortical bone differentiates into fibro-lamellar tissue that tends to become more regularly layered in the outer cortex. By the sub-adult stage, lines of arrested growth (LAGs) begin to appear regularly. Resorption lines and substantial Haversian substitution in many long bones also begin to appear at this stage, and the external cortex has a lamellar-zonal structure in some bones that indicates imminent cessation of growth. Judging by the rates of apposition of similar bone tissues in living amniotes, and by the number and placement of LAGs, these patterns suggest that young Maiasaura nestlings grew at very high rates, and at high and moderately high rates during later nestling, juvenile, and sub-adult stages, slowing to low and very low growth rates in adults (7–9 m total length). The nesting period would have lasted one to two months, late juvenile size (3.5 meters) would have been reached in one or two years, and adult size in six to eight years, depending on the basis for extrapolating bone growth rates. The histological tissues, patterns, and inferred growth rates of the bones of Maiasaura are completely different from those of living non-avian reptiles, generally similar to those of most other dinosaurs and pterosaurs for which data are available, and much like those of extant birds and mammals. No living reptiles (except birds) grow to adult size at these rates, nor do they show these histological patterns. We conclude that Maiasaura did not grow at all like living non-avian reptiles, which cannot be considered informative models for most aspects of dinosaurian growth (or physiology, to the extent that growth rates reflect metabolism). The use of lines of arrested growth (LAGs) to infer dinosaurian physiology has never been tested and is not supported by independent lines of evidence; their use in calculating age is also more complex than previously suggested and should not be based on single bones.

@article{doi1016710272463420000200115lbhoth20co2,
    author = "Horner, John R. and de Ricqlès, Armand and Padian, Kevin",
    title = "Long bone histology of the hadrosaurid dinosaur Maiasaura peeblesorum: growth dynamics and physiology based on an ontogenetic series of skeletal elements",
    year = "2000",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Ontogenetic changes in the bone histology of Maiasaura peeblesorum are revealed by six relatively distinct but gradational growth stages: early and late nestling, early and late juvenile, sub-adult, and adult. These stages are distinguished not only by relative size but by changes in the histological patterns of bones at each stage. In general, the earliest stages are marked by spongy bone matrix with large vascular canals. Through growth, the cortical bone differentiates into fibro-lamellar tissue that tends to become more regularly layered in the outer cortex. By the sub-adult stage, lines of arrested growth (LAGs) begin to appear regularly. Resorption lines and substantial Haversian substitution in many long bones also begin to appear at this stage, and the external cortex has a lamellar-zonal structure in some bones that indicates imminent cessation of growth. Judging by the rates of apposition of similar bone tissues in living amniotes, and by the number and placement of LAGs, these patterns suggest that young Maiasaura nestlings grew at very high rates, and at high and moderately high rates during later nestling, juvenile, and sub-adult stages, slowing to low and very low growth rates in adults (7–9 m total length). The nesting period would have lasted one to two months, late juvenile size (3.5 meters) would have been reached in one or two years, and adult size in six to eight years, depending on the basis for extrapolating bone growth rates. The histological tissues, patterns, and inferred growth rates of the bones of Maiasaura are completely different from those of living non-avian reptiles, generally similar to those of most other dinosaurs and pterosaurs for which data are available, and much like those of extant birds and mammals. No living reptiles (except birds) grow to adult size at these rates, nor do they show these histological patterns. We conclude that Maiasaura did not grow at all like living non-avian reptiles, which cannot be considered informative models for most aspects of dinosaurian growth (or physiology, to the extent that growth rates reflect metabolism). The use of lines of arrested growth (LAGs) to infer dinosaurian physiology has never been tested and is not supported by independent lines of evidence; their use in calculating age is also more complex than previously suggested and should not be based on single bones.",
    url = "https://doi.org/10.1671/0272-4634(2000)020[0115:lbhoth]2.0.co;2",
    doi = "10.1671/0272-4634(2000)020[0115:lbhoth]2.0.co;2",
    openalex = "W2179073245",
    references = "chinsamy1994dinosaur, chinsamy1998polar, doi101001jama195602970180082039, doi101002jmor1051080103, doi1010079781489957405, doi101017s0094837300012331, doi101017s0094837300013543, doi101017s0094837300021308, doi101029sc005p0175, doi101038282296a0, doi10108002724634199310011490, doi101093clinids222240, doi101126science26251422020, doi1016660094837320010270039coosea20co2, doi105962bhltitle113905, openalexw2259112626, openalexw648632191, openalexw991367939, reid1984primary"
}

Patterns of bone microstructure have frequently been used to deduce dynamics and processes of growth in extant and fossil tetrapods. Often, the various types of primary bone tissue have been associated with different bone deposition rates and more recently such deductions have extended to patterns observed in dinosaur bone microstructure. These previous studies are challenged by the findings of the current research, which integrates an experimental neontological approach and a paleontological comparison. We use tetracycline labeling and morphometry to study the variability of bone deposition rates in Japanese quail (Coturnix japonica) growing under different experimental conditions. We compare resulting patterns in bone microstructure with those found in fossil birds and other dinosaurs. We found that a single type of primary bone varies significantly in rates of growth in response to environmental conditions. Ranging between 10-50 microm per day, rates of growth overlap with the full range of bone deposition rates that were previously associated with different patterns of bone histology. Bone formation rate was significantly affected by environmental/experimental conditions, skeletal element, and age. In the quail, the experimental conditions did not result in formation of lines of arrested growth (LAGs). Because of the observed variation of bone deposition rates in response to variation in environmental conditions, we conclude that bone deposition rates measured in extant birds cannot simply be extrapolated to their fossil relatives. Additionally, we observe the variable incidence of LAGs and annuli among several dinosaur species, including fossil birds, extant sauropsids, as well as nonmammalian synapsids, and some extant mammals. This suggests that the ancestral condition of the response of bone to environmental conditions was variable. We propose that such developmental plasticity in modern birds may be reduced in association with the shortened developmental time during the later evolution of the ornithurine birds.

@article{doi101002jmor10029,
    author = "Starck, J. Matthias and Chinsamy, Anusuya",
    title = "Bone microstructure and developmental plasticity in birds and other dinosaurs",
    year = "2002",
    journal = "Journal of Morphology",
    abstract = "Patterns of bone microstructure have frequently been used to deduce dynamics and processes of growth in extant and fossil tetrapods. Often, the various types of primary bone tissue have been associated with different bone deposition rates and more recently such deductions have extended to patterns observed in dinosaur bone microstructure. These previous studies are challenged by the findings of the current research, which integrates an experimental neontological approach and a paleontological comparison. We use tetracycline labeling and morphometry to study the variability of bone deposition rates in Japanese quail (Coturnix japonica) growing under different experimental conditions. We compare resulting patterns in bone microstructure with those found in fossil birds and other dinosaurs. We found that a single type of primary bone varies significantly in rates of growth in response to environmental conditions. Ranging between 10-50 microm per day, rates of growth overlap with the full range of bone deposition rates that were previously associated with different patterns of bone histology. Bone formation rate was significantly affected by environmental/experimental conditions, skeletal element, and age. In the quail, the experimental conditions did not result in formation of lines of arrested growth (LAGs). Because of the observed variation of bone deposition rates in response to variation in environmental conditions, we conclude that bone deposition rates measured in extant birds cannot simply be extrapolated to their fossil relatives. Additionally, we observe the variable incidence of LAGs and annuli among several dinosaur species, including fossil birds, extant sauropsids, as well as nonmammalian synapsids, and some extant mammals. This suggests that the ancestral condition of the response of bone to environmental conditions was variable. We propose that such developmental plasticity in modern birds may be reduced in association with the shortened developmental time during the later evolution of the ornithurine birds.",
    url = "https://doi.org/10.1002/jmor.10029",
    doi = "10.1002/jmor.10029",
    openalex = "W2064159002",
    references = "deklerk2000a, doi101016s0764446900001815, doi101017s0094837300013543, doi101017s0094837300021308, doi101038368196a0, doi10108002724634199310011490, doi101093clinids222240, doi101093oso97801951060840010001, doi1016660094837320000260466lhotts20co2, doi1016710272463420000200115lbhoth20co2, openalexw406909995"
}

Abstract The bone histology of gorgonopsian, therocephalian and cynodont genera, ranging from the Late Permian to Early Jurassic, was examined. The analysis reveals a predominance of cortical fibrolamellar bone tissue in most skeletal elements. The high prevalence of fibrolamellar bone tissue suggests an overall rapid osteogenesis, but interruptions in the form of annuli and/or LAGs do occur. Inter-elemental histovariation within individuals, such as primary tissue type, cortical porosity, LAGs and annuli, extent of secondary reconstruction and endosteal bone deposition, is observed. In general, propodials were found to have grown faster than epipodials. Distinct growth patterns were identified for each of the genera studied. These growth patterns vary from a cyclical growth pattern in the Late Permian gorgonopsian, Scylacops to fast, sustained growth in the Early Jurassic cynodont, Tritylodon. Growth patterns of contemporaneous genera are also noted and discussed. A possible trend towards fast growth, and an independent decrease or eventual loss of developmental plasticity within the therapsids, is proposed.

@article{doi1016710272463420040240634bhagpo20co2,
    author = "Ray, Sanghamitra and Botha, Jennifer and Chinsamy, Anusuya",
    title = "Bone histology and growth patterns of some nonmammalian therapsids",
    year = "2004",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "Abstract The bone histology of gorgonopsian, therocephalian and cynodont genera, ranging from the Late Permian to Early Jurassic, was examined. The analysis reveals a predominance of cortical fibrolamellar bone tissue in most skeletal elements. The high prevalence of fibrolamellar bone tissue suggests an overall rapid osteogenesis, but interruptions in the form of annuli and/or LAGs do occur. Inter-elemental histovariation within individuals, such as primary tissue type, cortical porosity, LAGs and annuli, extent of secondary reconstruction and endosteal bone deposition, is observed. In general, propodials were found to have grown faster than epipodials. Distinct growth patterns were identified for each of the genera studied. These growth patterns vary from a cyclical growth pattern in the Late Permian gorgonopsian, Scylacops to fast, sustained growth in the Early Jurassic cynodont, Tritylodon. Growth patterns of contemporaneous genera are also noted and discussed. A possible trend towards fast growth, and an independent decrease or eventual loss of developmental plasticity within the therapsids, is proposed.",
    url = "https://doi.org/10.1671/0272-4634(2004)024[0634:bhagpo]2.0.co;2",
    doi = "10.1671/0272-4634(2004)024[0634:bhagpo]2.0.co;2",
    openalex = "W2177443328",
    references = "openalexw406909995"
}

ABSTRACT Four distinct stages have been identified in the ontogeny of Diictodon feliceps based on variations in cortical thickness, organization of primary osteons, porosity, incidence of growth marks, and extent of endosteal reconstruction. In general, the cortex comprises fibrolamellar bone tissue suggesting rapid bone deposition and growth. In the initial two stages of growth, when up to 70% of adult size is attained, no growth marks interrupt the fibrolamellar tissue, indicating a sustained, fast growth. Growth marks appear late in ontogeny and indicate periods of slow or complete cessation of growth after which, fast growth resumed. Although growth was interrupted and much slower in the later stages, D. feliceps probably had an indeterminate growth strategy. Variations in cortical thickness, porosity, organization of primary osteons, and incidence of annuli and LAGs are observed between elements of the same individual, suggesting variable inter-elemental growth. The propodials had faster appositional growth than did the epipodials, with the humerus having grown much faster than the femur in the same individual. The high cortical thickness (RBT) and correspondingly low k values suggest that the limbs were selected for impact loading. The relatively high RBT and low k value of the humerus compared to other limb bones indicates that the forelimbs were more modified for postural support and digging.

@article{doi101671191414,
    author = "Ray, Sanghamitra and Chinsamy, Anusuya",
    title = "Diictodon feliceps (Therapsida, Dicynodontia): bone histology, growth, and biomechanics",
    year = "2004",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Four distinct stages have been identified in the ontogeny of Diictodon feliceps based on variations in cortical thickness, organization of primary osteons, porosity, incidence of growth marks, and extent of endosteal reconstruction. In general, the cortex comprises fibrolamellar bone tissue suggesting rapid bone deposition and growth. In the initial two stages of growth, when up to 70\% of adult size is attained, no growth marks interrupt the fibrolamellar tissue, indicating a sustained, fast growth. Growth marks appear late in ontogeny and indicate periods of slow or complete cessation of growth after which, fast growth resumed. Although growth was interrupted and much slower in the later stages, D. feliceps probably had an indeterminate growth strategy. Variations in cortical thickness, porosity, organization of primary osteons, and incidence of annuli and LAGs are observed between elements of the same individual, suggesting variable inter-elemental growth. The propodials had faster appositional growth than did the epipodials, with the humerus having grown much faster than the femur in the same individual. The high cortical thickness (RBT) and correspondingly low k values suggest that the limbs were selected for impact loading. The relatively high RBT and low k value of the humerus compared to other limb bones indicates that the forelimbs were more modified for postural support and digging.",
    url = "https://doi.org/10.1671/1914-14",
    doi = "10.1671/1914-14",
    openalex = "W2156977583",
    references = "openalexw406909995, openalexw78083794, reid1984primary"
}

Abstract: Examination of the bone microstructure of Lystrosaurus murrayi from India and South Africa reveals a predominance of fibrolamellar bone tissue, which suggests rapid periosteal osteogenesis and an overall fast growth. Four distinct ontogenetic stages have been identified based on tissue type, organization of the primary osteons, incidence of growth rings, secondary reconstruction and endosteal bone deposition. An indeterminate growth strategy is proposed for Lystrosaurus. Inter-elemental histovariability suggests differential growth rate of the skeletal elements within the same individual, and among different individuals. The high cortical thickness of the dorsal ribs, an extensive secondary reconstruction in the cortical region of different skeletal elements that resulted in erosionally enlarged channels from the perimedullary to the midcortical region, and trabecular infilling of the medullary region even in the diaphyseal sections of the limb bones suggest at least a semi-aquatic lifestyle for L. murrayi.

@article{doi101111j14754983200500513x,
    author = "Ray, Sanghamitra and Chinsamy, Anusuya and Bandyopadhyay, Saswati",
    title = "LYSTROSAURUS MURRAYI (THERAPSIDA, DICYNODONTIA): BONE HISTOLOGY, GROWTH AND LIFESTYLE ADAPTATIONS",
    year = "2005",
    journal = "Palaeontology",
    abstract = "Abstract: Examination of the bone microstructure of Lystrosaurus murrayi from India and South Africa reveals a predominance of fibrolamellar bone tissue, which suggests rapid periosteal osteogenesis and an overall fast growth. Four distinct ontogenetic stages have been identified based on tissue type, organization of the primary osteons, incidence of growth rings, secondary reconstruction and endosteal bone deposition. An indeterminate growth strategy is proposed for Lystrosaurus. Inter-elemental histovariability suggests differential growth rate of the skeletal elements within the same individual, and among different individuals. The high cortical thickness of the dorsal ribs, an extensive secondary reconstruction in the cortical region of different skeletal elements that resulted in erosionally enlarged channels from the perimedullary to the midcortical region, and trabecular infilling of the medullary region even in the diaphyseal sections of the limb bones suggest at least a semi-aquatic lifestyle for L. murrayi.",
    url = "https://doi.org/10.1111/j.1475-4983.2005.00513.x",
    doi = "10.1111/j.1475-4983.2005.00513.x",
    openalex = "W2116027471",
    references = "openalexw406909995, reid1984primary"
}

@article{martinsander2006bone,
    author = "Martin Sander, P. and Mateus, Octávio and Laven, Thomas and Knötschke, Nils",
    title = "Bone histology indicates insular dwarfism in a new Late Jurassic sauropod dinosaur",
    year = "2006",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature04633",
    doi = "10.1038/nature04633",
    number = "7094",
    openalex = "W1985815554",
    pages = "739-741",
    volume = "441",
    references = "doi1010160016714284900346, doi101016jtree200508012, doi10103835086500, doi101038nature02699, doi101046j10963642200200029x, doi101525california97805202420980030015, doi1016660094837320000260466lhotts20co2, doi1016660094837320010270039coosea20co2, doi1023073060311, doi10560219780801881206"
}

Scheyer, Torsten M., Sánchez-Villagra, Marcelo R. (2007): Carapace bone histology in the giant pleurodiran turtle Stupendemys geographicus: Phylogeny and function. Acta Palaeontologica Polonica 52 (1): 137-154, DOI: 10.5281/zenodo.13748904

@article{doi105281zenodo13748903,
    author = "Scheyer, Torsten M. and Sánchez‐Villagra, Marcelo R.",
    title = "Carapace bone histology in the giant pleurodiran turtle Stupendemys geographicus: Phylogeny and function",
    year = "2007",
    journal = "reroDoc Digital Library",
    abstract = "Scheyer, Torsten M., Sánchez-Villagra, Marcelo R. (2007): Carapace bone histology in the giant pleurodiran turtle Stupendemys geographicus: Phylogeny and function. Acta Palaeontologica Polonica 52 (1): 137-154, DOI: 10.5281/zenodo.13748904",
    url = "https://doi.org/10.5281/zenodo.13748903",
    doi = "10.5281/zenodo.13748903",
    openalex = "W833585591",
    references = "doi101139z79216"
}

Abstract Long bones (femora, humeri) are the most abundant remains of sauropod dinosaurs. Their length is a good proxy for body length and body mass, and their histology is informative about ontogenetic age. Here we provide a comparative assessment of histologic changes in growth series of several sauropod taxa, including diplodocids (Apatosaurus, Diplodocus, indeterminate Diplodocinae from the Tendaguru Beds and from the Morrison Formation), basal macronarians (Camarasaurus, Brachiosaurus, Europasaurus), and titanosaurs (Phuwiangosaurus, Ampelosaurus). A total of 167 long bones, mainly humeri and femora, and 18 limb girdle bones were sampled. Sampling was performed by core drilling at prescribed locations at midshaft, and 13 histologic ontogenetic stages (HOS stages) were recognized. Because growth of all sauropod long bones is quite uniform, with laminar fibrolamellar bone being the dominant tissue, HOS stages could be recognized across taxa, although with minor differences. Histologic ontogenetic stages generally correlate closely with body size and thus provide a means to resolve important issue like the ontogenetic status of questionable specimens. We hypothesize that sexual maturity was attained at HOS-8, well before maximum size was attained, but we did not find sexually differentiated growth trajectories subsequent to HOS-8. On the basis of HOS stages, we detected two morphotypes in the Camarasaurus sample, a small one (type 1) and a larger one (type 2), presumably representing different species or sexual dimorphism.

@article{doi1016660094837320080340247ositlb20co2,
    author = "Klein, Nicole and Sander, Martin",
    title = "Ontogenetic stages in the long bone histology of sauropod dinosaurs",
    year = "2008",
    journal = "Paleobiology",
    abstract = "Abstract Long bones (femora, humeri) are the most abundant remains of sauropod dinosaurs. Their length is a good proxy for body length and body mass, and their histology is informative about ontogenetic age. Here we provide a comparative assessment of histologic changes in growth series of several sauropod taxa, including diplodocids (Apatosaurus, Diplodocus, indeterminate Diplodocinae from the Tendaguru Beds and from the Morrison Formation), basal macronarians (Camarasaurus, Brachiosaurus, Europasaurus), and titanosaurs (Phuwiangosaurus, Ampelosaurus). A total of 167 long bones, mainly humeri and femora, and 18 limb girdle bones were sampled. Sampling was performed by core drilling at prescribed locations at midshaft, and 13 histologic ontogenetic stages (HOS stages) were recognized. Because growth of all sauropod long bones is quite uniform, with laminar fibrolamellar bone being the dominant tissue, HOS stages could be recognized across taxa, although with minor differences. Histologic ontogenetic stages generally correlate closely with body size and thus provide a means to resolve important issue like the ontogenetic status of questionable specimens. We hypothesize that sexual maturity was attained at HOS-8, well before maximum size was attained, but we did not find sexually differentiated growth trajectories subsequent to HOS-8. On the basis of HOS stages, we detected two morphotypes in the Camarasaurus sample, a small one (type 1) and a larger one (type 2), presumably representing different species or sexual dimorphism.",
    url = "https://doi.org/10.1666/0094-8373(2008)034[0247:ositlb]2.0.co;2",
    doi = "10.1666/0094-8373(2008)034[0247:ositlb]2.0.co;2",
    openalex = "W2177631336",
    references = "chinsamy1994dinosaur, doi101016jtree200508012, doi101029sc005p0175, doi101038nature04633, doi101046j10963642200200029x, doi101073pnas0708903105, doi10108002724634199310011490, doi101098rsbl20070254, doi101098rspb20042829, doi101111j109636422000tb02201x, doi1015159781400849505, doi1016660094837320000260466lhotts20co2, doi1016660094837320010270039coosea20co2, doi1016710272463420000200115lbhoth20co2, martinsander2006bone"
}

BACKGROUND: Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs. METHODOLOGY/PRINCIPAL FINDINGS: We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates. CONCLUSIONS/SIGNIFICANCE: The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.

@article{doi101371journalpone0007390,
    author = "Erickson, Gregory M. and Rauhut, Oliver W. M. and Zhou, Zhonghe and Turner, Alan H. and Inouye, Brian D. and Hu, Dongyu and Norell, Mark A.",
    title = "Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx",
    year = "2009",
    journal = "PLoS ONE",
    abstract = "BACKGROUND: Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs. METHODOLOGY/PRINCIPAL FINDINGS: We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates. CONCLUSIONS/SIGNIFICANCE: The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.",
    url = "https://doi.org/10.1371/journal.pone.0007390",
    doi = "10.1371/journal.pone.0007390",
    openalex = "W2036031391",
    references = "doi101007bf00344996, doi101016jtree200508012, doi101016s0764446900001815, doi101023a1008929526011, doi101029sc005p0175, doi101038nature02699, doi101086410622, doi101111j109636422000tb02201x, doi101111j1474919x1968tb00058x, doi101111j1474919x1973tb02636x, doi101126science1144066, doi101525california97805202420980030031, doi1016710272463420040240555gisdap20co2, openalexw1558456135, openalexw1607828269, openalexw3206657856"
}

@article{garilli2009first,
    author = "Garilli, Vittorio and Klein, Nicole and Buffetaut, Eric and Sander, Paul and Martin Pollina, Francesco and Galletti, Luca and Cillari, Azzurra and Guzzetta, Dario",
    title = "First dinosaur bone from Sicily identified by histology and its palaeobiogeographical implications",
    year = "2009",
    journal = "Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen",
    url = "https://doi.org/10.1127/0077-7749/2009/0252-0207",
    doi = "10.1127/0077-7749/2009/0252-0207",
    number = "2",
    openalex = "W2038838252",
    pages = "207-216",
    volume = "252",
    references = "doi101002jmor10406, doi101016jtree200508012, doi101016s0012825202000752, doi101029tc009i004p00641, doi101073pnas0708903105, doi101093clinids222240, doi101098rspb20042829, doi101111j109636422000tb02201x, doi1016660094837320080340247ositlb20co2, doi1016710272463420000200115lbhoth20co2"
}

Pneumatic (air-filled) postcranial bones are unique to birds among extant tetrapods. Unambiguous skeletal correlates of postcranial pneumaticity first appeared in the Late Triassic (approximately 210 million years ago), when they evolved independently in several groups of bird-line archosaurs (ornithodirans). These include the theropod dinosaurs (of which birds are extant representatives), the pterosaurs, and sauropodomorph dinosaurs. Postulated functions of skeletal pneumatisation include weight reduction in large-bodied or flying taxa, and density reduction resulting in energetic savings during foraging and locomotion. However, the influence of these hypotheses on the early evolution of pneumaticity has not been studied in detail previously. We review recent work on the significance of pneumaticity for understanding the biology of extinct ornithodirans, and present detailed new data on the proportion of the skeleton that was pneumatised in 131 non-avian theropods and Archaeopteryx. This includes all taxa known from significant postcranial remains. Pneumaticity of the cervical and anterior dorsal vertebrae occurred early in theropod evolution. This 'common pattern' was conserved on the line leading to birds, and is likely present in Archaeopteryx. Increases in skeletal pneumaticity occurred independently in as many as 12 lineages, highlighting a remarkably high number of parallel acquisitions of a bird-like feature among non-avian theropods. Using a quantitative comparative framework, we show that evolutionary increases in skeletal pneumaticity are significantly concentrated in lineages with large body size, suggesting that mass reduction in response to gravitational constraints at large body sizes influenced the early evolution of pneumaticity. However, the body size threshold for extensive pneumatisation is lower in theropod lineages more closely related to birds (maniraptorans). Thus, relaxation of the relationship between body size and pneumatisation preceded the origin of birds and cannot be explained as an adaptation for flight. We hypothesise that skeletal density modulation in small, non-volant, maniraptorans resulted in energetic savings as part of a multi-system response to increased metabolic demands. Acquisition of extensive postcranial pneumaticity in small-bodied maniraptorans may indicate avian-like high-performance endothermy.

@article{doi101111j1469185x201100190x,
    author = "Benson, Roger and Butler, Richard J. and Carrano, Matthew T. and O’Connor, Patrick M.",
    title = "Air‐filled postcranial bones in theropod dinosaurs: physiological implications and the ‘reptile’–bird transition",
    year = "2011",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "Pneumatic (air-filled) postcranial bones are unique to birds among extant tetrapods. Unambiguous skeletal correlates of postcranial pneumaticity first appeared in the Late Triassic (approximately 210 million years ago), when they evolved independently in several groups of bird-line archosaurs (ornithodirans). These include the theropod dinosaurs (of which birds are extant representatives), the pterosaurs, and sauropodomorph dinosaurs. Postulated functions of skeletal pneumatisation include weight reduction in large-bodied or flying taxa, and density reduction resulting in energetic savings during foraging and locomotion. However, the influence of these hypotheses on the early evolution of pneumaticity has not been studied in detail previously. We review recent work on the significance of pneumaticity for understanding the biology of extinct ornithodirans, and present detailed new data on the proportion of the skeleton that was pneumatised in 131 non-avian theropods and Archaeopteryx. This includes all taxa known from significant postcranial remains. Pneumaticity of the cervical and anterior dorsal vertebrae occurred early in theropod evolution. This 'common pattern' was conserved on the line leading to birds, and is likely present in Archaeopteryx. Increases in skeletal pneumaticity occurred independently in as many as 12 lineages, highlighting a remarkably high number of parallel acquisitions of a bird-like feature among non-avian theropods. Using a quantitative comparative framework, we show that evolutionary increases in skeletal pneumaticity are significantly concentrated in lineages with large body size, suggesting that mass reduction in response to gravitational constraints at large body sizes influenced the early evolution of pneumaticity. However, the body size threshold for extensive pneumatisation is lower in theropod lineages more closely related to birds (maniraptorans). Thus, relaxation of the relationship between body size and pneumatisation preceded the origin of birds and cannot be explained as an adaptation for flight. We hypothesise that skeletal density modulation in small, non-volant, maniraptorans resulted in energetic savings as part of a multi-system response to increased metabolic demands. Acquisition of extensive postcranial pneumaticity in small-bodied maniraptorans may indicate avian-like high-performance endothermy.",
    url = "https://doi.org/10.1111/j.1469-185x.2011.00190.x",
    doi = "10.1111/j.1469-185x.2011.00190.x",
    openalex = "W2003924744",
    references = "doi101002jez513, doi101002jmor10470, doi101002sici1097018520000215261125aidar630co27, doi101007s0011400804883, doi101007s001140090614x, doi101017s0094837300021308, doi101038nature07856, doi101073pnas0708903105, doi10108002724634199710011018, doi101086284325, doi101093auk12041206, doi101093bioinformaticsbtg412, doi101093sysbio41118, doi101098rstb19890106, doi101111j10963642200600245x, doi101111j10963642200900569x, doi101126science1180219, doi1012066481, doi101371journalpone0003303, doi101371journalpone0007390, doi10167102724634200727127tpasom20co2, doi1023071292217, doi1023071441916, doi105281zenodo16171435, doi105860choice392183, doi105860choice434677, doi105962bhltitle60562, openalexw2611511275, openalexw3086315876, ostrom2019osteology, owen1857monograph, owen2015monograph"
}

List of Contributors Preface List of Institutional Abbreviations Introduction 1. Sauropod Biology and the Evolution of Gigantism: What Do We Know? / Marcus Clauss Part 1. Nutrition 2. Sauropod Feeding and Digestive Physiology / Jurgen Hummel and Marcus Clauss 3. Dietary Options for the Sauropod Dinosaurs from an Integrated Botanical and Paleobotanical Perspective / Carole T. Gee 4. The Diet of Sauropod Dinosaurs: Implications of Carbon Isotope Analysis on Teeth, Bones, and Plants / Thomas Tutken Part 2. Physiology 5. Structure and Function of the Sauropod Respiratory System / Steven F. Perry, Thomas Breuer, and Nadine Pajor 6. Reconstructing Body Volume and Surface Area of Dinosaurs Using Laser Scanning and Photogrammetry / Stefan Stoinski, Tim Suthau, and Hanns-Christian Gunga 7. Body Mass Estimation, Thermoregulation, and Cardiovascular Physiology of Large Sauropods / Bergita Ganse, Alexander Stahn, Stefan Stoinski, Tim Suthau, and Hanns-Christian Gunga Part 3. Construction 8. How to Get Big in the Mesozoic: The Evolution of the Sauropodomorph Body Plan / Oliver W. M. Rauhut, Regina Fechner, Kristian Remes, and Katrin Reis 9. Characterization of Sauropod Bone Structure / Maitena Dumont, Anke Pyzalla, Aleksander Kostka, and Andras Borbely 10. Finite Element Analyses and Virtual Syntheses of Biological Structures and Their Application to Sauropod Skulls / Ulrich Witzel, Julia Mannhardt, Rainer Goessling, Pascal de Micheli, and Holger Preuschoft 11. Walking with the Shoulder of Giants: Biomechanical Conditions in the Tetrapod Shoulder Girdle as a Basis for Sauropod Shoulder Reconstruction / Bianca Hohn 12. Why So Huge? Biomechanical Reasons for the Acquisition of Large Size in Sauropod and Theropod Dinosaurs / Holger Preuschoft, Bianca Hohn, Stefan Stoinski, and Ulrich Witzel 13. Plateosaurus in 3D: How CAD Models and Kinetic-Dynamic Modeling Bring an Extinct Animal to Life / Heinrich Mallison 14. Rearing Giants: Kinetic-Dynamic Modeling of Sauropod Bipedal and Tripodal Poses / Heinrich Mallison 15. Neck Posture in Sauropods / Andreas Christian and Gordon Dzemski Part 4. Growth 16. The Life Cycle of Sauropod Dinosaurs / Eva-Maria Griebeler and Jan Werner 17. Sauropod Bone Histology and Its Implications for Sauropod Biology / P. Martin Sander, Nicole Klein, Koen Stein, and Oliver Wings Part 5. Epilogue 18. Skeletal Reconstruction of Brachiosaurus brancai in the Museum fur Naturkunde, Berlin: Summarizing 70 Years of Sauropod Research / Kristian Remes, David M. Unwin, Nicole Klein, Wolf-Dieter Heinrich, and Oliver Hampe Appendix: Compilation of Published Body Mass Data for a Variety of Basal Sauropodomorphs and Sauropods Index

@article{doi105860choice490282,
    title = "Biology of the sauropod dinosaurs: understanding the life of giants",
    year = "2011",
    journal = "Choice Reviews Online",
    abstract = "List of Contributors Preface List of Institutional Abbreviations Introduction 1. Sauropod Biology and the Evolution of Gigantism: What Do We Know? / Marcus Clauss Part 1. Nutrition 2. Sauropod Feeding and Digestive Physiology / Jurgen Hummel and Marcus Clauss 3. Dietary Options for the Sauropod Dinosaurs from an Integrated Botanical and Paleobotanical Perspective / Carole T. Gee 4. The Diet of Sauropod Dinosaurs: Implications of Carbon Isotope Analysis on Teeth, Bones, and Plants / Thomas Tutken Part 2. Physiology 5. Structure and Function of the Sauropod Respiratory System / Steven F. Perry, Thomas Breuer, and Nadine Pajor 6. Reconstructing Body Volume and Surface Area of Dinosaurs Using Laser Scanning and Photogrammetry / Stefan Stoinski, Tim Suthau, and Hanns-Christian Gunga 7. Body Mass Estimation, Thermoregulation, and Cardiovascular Physiology of Large Sauropods / Bergita Ganse, Alexander Stahn, Stefan Stoinski, Tim Suthau, and Hanns-Christian Gunga Part 3. Construction 8. How to Get Big in the Mesozoic: The Evolution of the Sauropodomorph Body Plan / Oliver W. M. Rauhut, Regina Fechner, Kristian Remes, and Katrin Reis 9. Characterization of Sauropod Bone Structure / Maitena Dumont, Anke Pyzalla, Aleksander Kostka, and Andras Borbely 10. Finite Element Analyses and Virtual Syntheses of Biological Structures and Their Application to Sauropod Skulls / Ulrich Witzel, Julia Mannhardt, Rainer Goessling, Pascal de Micheli, and Holger Preuschoft 11. Walking with the Shoulder of Giants: Biomechanical Conditions in the Tetrapod Shoulder Girdle as a Basis for Sauropod Shoulder Reconstruction / Bianca Hohn 12. Why So Huge? Biomechanical Reasons for the Acquisition of Large Size in Sauropod and Theropod Dinosaurs / Holger Preuschoft, Bianca Hohn, Stefan Stoinski, and Ulrich Witzel 13. Plateosaurus in 3D: How CAD Models and Kinetic-Dynamic Modeling Bring an Extinct Animal to Life / Heinrich Mallison 14. Rearing Giants: Kinetic-Dynamic Modeling of Sauropod Bipedal and Tripodal Poses / Heinrich Mallison 15. Neck Posture in Sauropods / Andreas Christian and Gordon Dzemski Part 4. Growth 16. The Life Cycle of Sauropod Dinosaurs / Eva-Maria Griebeler and Jan Werner 17. Sauropod Bone Histology and Its Implications for Sauropod Biology / P. Martin Sander, Nicole Klein, Koen Stein, and Oliver Wings Part 5. Epilogue 18. Skeletal Reconstruction of Brachiosaurus brancai in the Museum fur Naturkunde, Berlin: Summarizing 70 Years of Sauropod Research / Kristian Remes, David M. Unwin, Nicole Klein, Wolf-Dieter Heinrich, and Oliver Hampe Appendix: Compilation of Published Body Mass Data for a Variety of Basal Sauropodomorphs and Sauropods Index",
    url = "https://doi.org/10.5860/choice.49-0282",
    doi = "10.5860/choice.49-0282",
    openalex = "W293512402",
    references = "amiot2006oxygen, christiansen2004mass, doi101002mmng200900004, doi1010160012825273900287, doi1010160031018275900279, doi1010160375650595000240, doi101016b9780126764604500081, doi101016jpalaeo200401006, doi101016jpalaeo200901002, doi101017cbo9780511608551, doi101017cbo9781139167826, doi101017s009483730000676x, doi101017s0094837300009866, doi101038229172a0, doi101038262207a0, doi10103835086558, doi101038nature00930, doi101038nature04633, doi101046j10963642200200029x, doi101073pnas251548698, doi101073pnas932514623, doi10108002724634199910011178, doi101111j1469185x201000137x, doi101111j146979981985tb04915x, doi101126science1138709, doi101242jeb02443, doi101525california97805202462320010001, doi1016660094837320000260734aaateo20co2, doi1016660094837320030290105dbttoo20co2, doi1016660094837320030290243vpasat20co2, doi1016660094837320080340247ositlb20co2, doi101666080251, doi1016710272463420020220766tehits20co2, doi1023071310735, doi1023073515313, doi104039ent912935, doi105860choice271523, doi105860choice324505, doi105962bhltitle118957, martinsander2006bone, openalexw1534857865, openalexw1558456135, openalexw1590241584, openalexw2473973115, openalexw2729191089, openalexw603337959, seymour1976dinosaurs"
}

BACKGROUND: Rhabdodontid ornithopod dinosaurs are characteristic elements of Late Cretaceous European vertebrate faunas and were previously collected from lower Campanian to Maastrichtian continental deposits. Phylogenetic analyses have placed rhabdodontids among basal ornithopods as the sister taxon to the clade consisting of Tenontosaurus, Dryosaurus, Camptosaurus, and Iguanodon. Recent studies considered Zalmoxes, the best known representative of the clade, to be significantly smaller than closely related ornithopods such as Tenontosaurus, Camptosaurus, or Rhabdodon, and concluded that it was probably an island dwarf that inhabited the Maastrichtian Haţeg Island. METHODOLOGY/PRINCIPAL FINDINGS: Rhabdodontid remains from the Santonian of western Hungary provide evidence for a new, small-bodied form, which we assign to Mochlodon vorosi n. sp. The new species is most similar to the early Campanian M. suessi from Austria, and the close affinities of the two species is further supported by the results of a global phylogenetic analysis of ornithischian dinosaurs. Bone histological studies of representatives of all rhabdodontids indicate a similar adult body length of 1.6-1.8 m in the Hungarian and Austrian species, 2.4-2.5 m in the subadults of both Zalmoxes robustus and Z. shqiperorum and a much larger, 5-6 m adult body length in Rhabdodon. Phylogenetic mapping of femoral lengths onto the results of the phylogenetic analysis suggests a femoral length of around 340 mm as the ancestral state for Rhabdodontidae, close to the adult femoral lengths known for Zalmoxes (320-333 mm). CONCLUSIONS/SIGNIFICANCE: Our analysis of body size evolution does not support the hypothesis of autapomorhic nanism for Zalmoxes. However, Rhabdodon is reconstructed as having undergone autapomorphic giantism and the reconstructed small femoral length (245 mm) of Mochlodon is consistent with a reduction in size relative to the ancestral rhabdodontid condition. Our results imply a pre-Santonian divergence between western and eastern rhabdodontid lineages within the western Tethyan archipelago.

@article{doi101371journalpone0044318,
    author = "Ősi, Attila and Prondvai, Edina and Butler, Richard J. and Weishampel, David B.",
    title = "Phylogeny, Histology and Inferred Body Size Evolution in a New Rhabdodontid Dinosaur from the Late Cretaceous of Hungary",
    year = "2012",
    journal = "PLoS ONE",
    abstract = "BACKGROUND: Rhabdodontid ornithopod dinosaurs are characteristic elements of Late Cretaceous European vertebrate faunas and were previously collected from lower Campanian to Maastrichtian continental deposits. Phylogenetic analyses have placed rhabdodontids among basal ornithopods as the sister taxon to the clade consisting of Tenontosaurus, Dryosaurus, Camptosaurus, and Iguanodon. Recent studies considered Zalmoxes, the best known representative of the clade, to be significantly smaller than closely related ornithopods such as Tenontosaurus, Camptosaurus, or Rhabdodon, and concluded that it was probably an island dwarf that inhabited the Maastrichtian Haţeg Island. METHODOLOGY/PRINCIPAL FINDINGS: Rhabdodontid remains from the Santonian of western Hungary provide evidence for a new, small-bodied form, which we assign to Mochlodon vorosi n. sp. The new species is most similar to the early Campanian M. suessi from Austria, and the close affinities of the two species is further supported by the results of a global phylogenetic analysis of ornithischian dinosaurs. Bone histological studies of representatives of all rhabdodontids indicate a similar adult body length of 1.6-1.8 m in the Hungarian and Austrian species, 2.4-2.5 m in the subadults of both Zalmoxes robustus and Z. shqiperorum and a much larger, 5-6 m adult body length in Rhabdodon. Phylogenetic mapping of femoral lengths onto the results of the phylogenetic analysis suggests a femoral length of around 340 mm as the ancestral state for Rhabdodontidae, close to the adult femoral lengths known for Zalmoxes (320-333 mm). CONCLUSIONS/SIGNIFICANCE: Our analysis of body size evolution does not support the hypothesis of autapomorhic nanism for Zalmoxes. However, Rhabdodon is reconstructed as having undergone autapomorphic giantism and the reconstructed small femoral length (245 mm) of Mochlodon is consistent with a reduction in size relative to the ancestral rhabdodontid condition. Our results imply a pre-Santonian divergence between western and eastern rhabdodontid lineages within the western Tethyan archipelago.",
    url = "https://doi.org/10.1371/journal.pone.0044318",
    doi = "10.1371/journal.pone.0044318",
    openalex = "W2004173110",
    references = "doi101002jmor10524, doi101007978140206754912413, doi101016s1631068303000022, doi101080027246342012694385, doi101098rspl18870117, doi101111j10960031200800209x, doi101111j1469185x201000137x, doi101371journalpbio0040321, doi101371journalpone0029958, doi102307jctt1zxz1md6, doi102475ajss31695411, doi102475ajss319111253, doi105281zenodo16673433, doi105860choice393984, doi105860choice503272, doi105962p313819, openalexw225597919"
}

@article{köhler2012seasonal,
    author = "Köhler, Meike and Marín-Moratalla, Nekane and Jordana, Xavier and Aanes, Ronny",
    title = "Seasonal bone growth and physiology in endotherms shed light on dinosaur physiology",
    year = "2012",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature11264",
    doi = "10.1038/nature11264",
    number = "7407",
    openalex = "W2087820262",
    pages = "358-361",
    volume = "487",
    references = "doi101007s0044201016215, doi101016s1095643303003118, doi101016s1631069102014294, doi101017s1751731107000262, doi101111j13652435201001806x, doi101111j160005872000tb00300x, doi101643004585112002002117020co2, doi1016660094837320080340247ositlb20co2, doi1023071445584, doi105194hess1116332007"
}

PREFACE: James O. Farlow and M. K. Brett-Surman PART ONE: THE DISCOVERY OF DINOSAURS The Earliest Discoveries: William A. S. Sarjeant European Dinosaur Hunters: Hans-Dieter Sues North American Dinosaur Hunters: Edwin H. Colbert Asian Dinosaur Hunters: John R. Lavas Dinosaur Hunters of the Southern Continents: Thomas R. Holtz, Jr. PART TWO: THE STUDY OF DINOSAURS Hunting for Dinosaur Bones: David D. Gillette The Osteology of the Dinosaurs: Thomas R. Holtz, Jr. and M. K.Brett-Surman The Taxonomy and Systematics of the Dinosaurs: Thomas R. Holtz, Jr. and M. K. Brett-Surman Dinosaurs and Geologic Time: James O. Farlow The Scientific Study of Dinosaurs: Ralph E. Chapman Molecular Paleontology: Rationale and Techniques for the Study of Ancient Biomolecules: Mary Higby Schweitzer Dinosaurs as Museum Exhibits: Kenneth Carpenter Restoring Dinosaurs as Living Animals: Douglas Henderson PART THREE: THE GROUPS OF DINOSAURS Introduction: James O. Farlow and M. K. Brett-Surman Politics and Paleontology: Richard Owen and the Invention of Dinosaurs: Hugh Torrens Evolution of the Archosaurs: J. Michael Parrish Origin and Early Evolution of Dinosaurs: Michael J. Benton Theropods: Philip J. Currie Segnosaurs (Therezinosaurs): Teresa Maryanska Prosauropods: Jacques VanHeerden Sauropods: John S. McIntosh, M. K. Brett-Surman, and James O. Farlow Stegosaurs: Peter M. Galton Ankylosaurs: Kenneth Carpenter Marginocephalians: Catherine A. Forster and Paul C. Sereno Ornithopods: M. K. Brett-Surman PART FOUR: BIOLOGY OF THE DINOSAURS Land Plants as Food and Habitat in the Age of Dinosaurs: Bruce H. Tiffney What Did Dinosaurs Eat? Coprolites and Other Direct Evidence of Dinosaur Diets: Karen Chin Dinosaur Combat and Courtship: Scott Sampson Dinosaur Eggs: Karl F. Hirsch and Darla K. Zelenitsky How Dinosaurs Grew: R. E. H. Reid Engineering a Dinosaur: R. McN. Alexander Dinosaurian Paleopathology: Bruce M. Rothschild Dinosaurian Physiology: the Case for Intermediate Dinosaurs: R. E. H. Reid Oxygen Isotopes in Dinosaur Bone: Reese E. Barrick, Michael K. Stoskopf, and William J. Showers A Blueprint for Giants: Do Living Reptiles, Birds or Mammals Provide the Best Model for the Physiology of Large Dinosaurs? Frank V. Paladino, James R. Spotila, and Peter Dodson New Insights into the Metabolic Physiology of Dinosaurs: John Ruben, Andrew Leitch, Willem Hillenius, Nicholas Geist, and Terry Jones The Scientific Study of Dinosaur Footprints: James O. Farlow and Ralph E. Chapman The Paleoecological and Paleoenvironmental Utility of Dinosaur Tracks: Martin G. Lockley PART FIVE: DINOSAUR EVOLUTION IN THE CHANGING WORLD OF THE MESOZOIC ERA Biogeography for Dinosaurs: Ralph E. Molnar Major Groups of Non-Dinosaurian Vertebrates of the Mesozoic Era: Michael Morales Continental Tetrapods of the Early Mesozoic: Faunas and Faunal Changes: Hans-Dieter Sues Dinosaurian Faunas of the Later Mesozoic: Dale A. Russell and Jose F. Bonaparte The Extinction of the Dinosaurs: A Dialogue Between a Catastrophist and a Gradualist: Dale A. Russell and Peter Dodson PART SIX: DINOSAURS AND THE MEDIA Dinosaurs and the Media: Donald F. Glut and M. K. Brett-Surman APPENDIX: A CHRONOLOGICAL HISTORY OF DINOSAUR PALEONTOLOGY: M. K. Brett-Surman GLOSSARY CONTRIBUTORS INDEX

@book{openalexw1585246501,
    author = "Farlow, James O. and Brett-Surman, Michael K.",
    title = "The Complete Dinosaur",
    year = "2012",
    booktitle = "Opus: Research \& Creativity (Indiana University – Purdue University Fort Wayne)",
    abstract = "PREFACE: James O. Farlow and M. K. Brett-Surman PART ONE: THE DISCOVERY OF DINOSAURS The Earliest Discoveries: William A. S. Sarjeant European Dinosaur Hunters: Hans-Dieter Sues North American Dinosaur Hunters: Edwin H. Colbert Asian Dinosaur Hunters: John R. Lavas Dinosaur Hunters of the Southern Continents: Thomas R. Holtz, Jr. PART TWO: THE STUDY OF DINOSAURS Hunting for Dinosaur Bones: David D. Gillette The Osteology of the Dinosaurs: Thomas R. Holtz, Jr. and M. K.Brett-Surman The Taxonomy and Systematics of the Dinosaurs: Thomas R. Holtz, Jr. and M. K. Brett-Surman Dinosaurs and Geologic Time: James O. Farlow The Scientific Study of Dinosaurs: Ralph E. Chapman Molecular Paleontology: Rationale and Techniques for the Study of Ancient Biomolecules: Mary Higby Schweitzer Dinosaurs as Museum Exhibits: Kenneth Carpenter Restoring Dinosaurs as Living Animals: Douglas Henderson PART THREE: THE GROUPS OF DINOSAURS Introduction: James O. Farlow and M. K. Brett-Surman Politics and Paleontology: Richard Owen and the Invention of Dinosaurs: Hugh Torrens Evolution of the Archosaurs: J. Michael Parrish Origin and Early Evolution of Dinosaurs: Michael J. Benton Theropods: Philip J. Currie Segnosaurs (Therezinosaurs): Teresa Maryanska Prosauropods: Jacques VanHeerden Sauropods: John S. McIntosh, M. K. Brett-Surman, and James O. Farlow Stegosaurs: Peter M. Galton Ankylosaurs: Kenneth Carpenter Marginocephalians: Catherine A. Forster and Paul C. Sereno Ornithopods: M. K. Brett-Surman PART FOUR: BIOLOGY OF THE DINOSAURS Land Plants as Food and Habitat in the Age of Dinosaurs: Bruce H. Tiffney What Did Dinosaurs Eat? Coprolites and Other Direct Evidence of Dinosaur Diets: Karen Chin Dinosaur Combat and Courtship: Scott Sampson Dinosaur Eggs: Karl F. Hirsch and Darla K. Zelenitsky How Dinosaurs Grew: R. E. H. Reid Engineering a Dinosaur: R. McN. Alexander Dinosaurian Paleopathology: Bruce M. Rothschild Dinosaurian Physiology: the Case for Intermediate Dinosaurs: R. E. H. Reid Oxygen Isotopes in Dinosaur Bone: Reese E. Barrick, Michael K. Stoskopf, and William J. Showers A Blueprint for Giants: Do Living Reptiles, Birds or Mammals Provide the Best Model for the Physiology of Large Dinosaurs? Frank V. Paladino, James R. Spotila, and Peter Dodson New Insights into the Metabolic Physiology of Dinosaurs: John Ruben, Andrew Leitch, Willem Hillenius, Nicholas Geist, and Terry Jones The Scientific Study of Dinosaur Footprints: James O. Farlow and Ralph E. Chapman The Paleoecological and Paleoenvironmental Utility of Dinosaur Tracks: Martin G. Lockley PART FIVE: DINOSAUR EVOLUTION IN THE CHANGING WORLD OF THE MESOZOIC ERA Biogeography for Dinosaurs: Ralph E. Molnar Major Groups of Non-Dinosaurian Vertebrates of the Mesozoic Era: Michael Morales Continental Tetrapods of the Early Mesozoic: Faunas and Faunal Changes: Hans-Dieter Sues Dinosaurian Faunas of the Later Mesozoic: Dale A. Russell and Jose F. Bonaparte The Extinction of the Dinosaurs: A Dialogue Between a Catastrophist and a Gradualist: Dale A. Russell and Peter Dodson PART SIX: DINOSAURS AND THE MEDIA Dinosaurs and the Media: Donald F. Glut and M. K. Brett-Surman APPENDIX: A CHRONOLOGICAL HISTORY OF DINOSAUR PALEONTOLOGY: M. K. Brett-Surman GLOSSARY CONTRIBUTORS INDEX",
    openalex = "W1585246501",
    references = "chatterjee2013a, chinsamy1998polar, deklerk2000a, doi101002ar20982, doi101002ara10097, doi101002jmor10406, doi101007s0011400804883, doi1010160031018291900605, doi1010160034666781900695, doi101016jannpal200803002, doi101016jepsl200801015, doi101016jpalaeo201002025, doi101017cbo9780511608551, doi101017s0022336000018862, doi101017s0094837300007557, doi101017s0094837300016900, doi101017s0094837300021321, doi101038262207a0, doi101038307360a0, doi10103832884, doi101038359117a0, doi101038362709a0, doi101038368196a0, doi101038nature03635, doi101038nature10906, doi101046j14401738200300386x, doi10108002724634199810011086, doi10108002724634199910011125, doi10108008912960903503345, doi10108010420940802471027, doi101086284406, doi101086422766, doi101098rspb20060443, doi101111j10963642200600245x, doi101111j10963642200900631x, doi101111j1469185x200900107x, doi101111j150239311985tb00690x, doi101111j15023931200900187x, doi101126science1157704, doi101126science1180219, doi101126science172397867, doi101126science24248841403, doi101126science27352791204, doi101127njgpm19831983141, doi1011300091761319930210503pioatv23co2, doi101130g23452a1, doi101130spe40p1, doi101144001676492006032, doi101144gslsp20042280106, doi101146annurevearth040610133502, doi101146annurevearth28119, doi101146annurevgenet37110801143214, doi10120600030082200635301ydanpc20co2, doi1012066391, doi101353book59141, doi101371journalpone0012292, doi1016660094837320000260450fpindi20co2, doi1016660094837320050310291teafot20co2, doi1016690883135120030180286rpoumt20co2, doi1016710272463420020220593cvancf20co2, doi1016710272463420020220766tehits20co2, doi101671a11168, doi102110palo2007p07070r, doi1023071445147, doi1023073514548, doi102475ajss425149387, doi104202app20080049, doi105281zenodo13315375, doi105281zenodo16692311, doi105281zenodo3739898, doi105962p339375, fiorillo2004the, jacobsen1998feeding, lehman1987late, nelson1980counts, openalexw1550095290, openalexw1558456135, openalexw2163397885, openalexw2242116350, openalexw2506868775, pontzer2009biomechanics, russell2002synopsis, seymour1976dinosaurs, sloan1986gradual, stevens2006binocular, witmer1991biomechanics, woodward1910on"
}

Bone microstructure reflects physiological characteristics and has been shown to contain phylogenetic and ecological signals. Although mammalian long bone histology is receiving increasing attention, systematic examination of the main clades has not yet been performed. Here we describe the long bone microstructure of Xenarthra based on thin sections representing twenty-two species. Additionally, patterns in bone compactness of humeri and femora are investigated. The primary bone tissue of xenarthran long bones is composed of a mixture of woven, parallel-fibered and lamellar bone. The vascular canals have a longitudinal, reticular or radial orientation and are mostly arranged in an irregular manner. Concentric rows of vascular canals and laminar organization of the tissue are only found in anteater bones. The long bones of adult specimens are marked by dense Haversian bone, a feature that has been noted for most groups of mammals. In the long bones of armadillos, secondary osteons have an oblique orientation within the three-dimensional bone tissue, thus resulting in their irregular shape when the bones are sectioned transversely. Secondary remodeling is generally more extensive in large taxa than in small taxa, and this could be caused by increased loading. Lines of arrested growth are assumed to be present in all specimens, but they are restricted to the outermost layer in bones of armadillos and are often masked by secondary remodeling in large taxa. Parameters of bone compactness show a pattern in the femur that separates Cingulata and Pilosa (Folivora and Vermilingua), with cingulates having a lower compactness than pilosans. In addition, cingulates show an allometric relationship between humeral and femoral bone compactness.

@article{doi101371journalpone0069275,
    author = "Straehl, Fiona R. and Scheyer, Torsten M. and Forasiepi, Analía M. and MacPhee, R. D. E. and Sánchez‐Villagra, Marcelo R.",
    title = "Evolutionary Patterns of Bone Histology and Bone Compactness in Xenarthran Mammal Long Bones",
    year = "2013",
    journal = "PLoS ONE",
    abstract = "Bone microstructure reflects physiological characteristics and has been shown to contain phylogenetic and ecological signals. Although mammalian long bone histology is receiving increasing attention, systematic examination of the main clades has not yet been performed. Here we describe the long bone microstructure of Xenarthra based on thin sections representing twenty-two species. Additionally, patterns in bone compactness of humeri and femora are investigated. The primary bone tissue of xenarthran long bones is composed of a mixture of woven, parallel-fibered and lamellar bone. The vascular canals have a longitudinal, reticular or radial orientation and are mostly arranged in an irregular manner. Concentric rows of vascular canals and laminar organization of the tissue are only found in anteater bones. The long bones of adult specimens are marked by dense Haversian bone, a feature that has been noted for most groups of mammals. In the long bones of armadillos, secondary osteons have an oblique orientation within the three-dimensional bone tissue, thus resulting in their irregular shape when the bones are sectioned transversely. Secondary remodeling is generally more extensive in large taxa than in small taxa, and this could be caused by increased loading. Lines of arrested growth are assumed to be present in all specimens, but they are restricted to the outermost layer in bones of armadillos and are often masked by secondary remodeling in large taxa. Parameters of bone compactness show a pattern in the femur that separates Cingulata and Pilosa (Folivora and Vermilingua), with cingulates having a lower compactness than pilosans. In addition, cingulates show an allometric relationship between humeral and femoral bone compactness.",
    url = "https://doi.org/10.1371/journal.pone.0069275",
    doi = "10.1371/journal.pone.0069275",
    openalex = "W2007201384",
    references = "doi101016jcrpv200510006, doi101017s0952836904004844, doi101111j10958312201001431x, doi101371journalpone0033539"
}

). For nearly two centuries, plesiosaurians were thought to appear suddenly in the earliest Jurassic after the end-Triassic extinctions. We describe the first Triassic plesiosaurian, from the Rhaetian of Germany, and compare its long bone histology to that of later plesiosaurians sampled for this study. The new taxon is recovered as a basal member of the Pliosauridae, revealing that diversification of plesiosaurians was a Triassic event and that several lineages must have crossed into the Jurassic. Plesiosaurian histology is strikingly uniform and different from stem sauropterygians. Histology suggests the concurrent evolution of fast growth and an elevated metabolic rate as an adaptation to cruising and efficient foraging in the open sea. The new specimen corroborates the hypothesis that open ocean life of plesiosaurians facilitated their survival of the end-Triassic extinctions.

@article{doi101126sciadv1701144,
    author = "Wintrich, Tanja and Hayashi, Shoji and Houssaye, Alexandra and Nakajima, Yasuhisa and Sander, P. Martin",
    title = "A Triassic plesiosaurian skeleton and bone histology inform on evolution of a unique body plan",
    year = "2017",
    journal = "Science Advances",
    abstract = "). For nearly two centuries, plesiosaurians were thought to appear suddenly in the earliest Jurassic after the end-Triassic extinctions. We describe the first Triassic plesiosaurian, from the Rhaetian of Germany, and compare its long bone histology to that of later plesiosaurians sampled for this study. The new taxon is recovered as a basal member of the Pliosauridae, revealing that diversification of plesiosaurians was a Triassic event and that several lineages must have crossed into the Jurassic. Plesiosaurian histology is strikingly uniform and different from stem sauropterygians. Histology suggests the concurrent evolution of fast growth and an elevated metabolic rate as an adaptation to cruising and efficient foraging in the open sea. The new specimen corroborates the hypothesis that open ocean life of plesiosaurians facilitated their survival of the end-Triassic extinctions.",
    url = "https://doi.org/10.1126/sciadv.1701144",
    doi = "10.1126/sciadv.1701144",
    openalex = "W2773038171",
    references = "doi101038nature11264, doi101093sysbiosyw033, doi101126scienceaaa3716, doi101371journalpone0011613, doi101371journalpone0031838, doi101371journalpone0088834, köhler2012seasonal"
}

In the mid-19th century, the discovery that bone microstructure in fossils could be preserved with fidelity provided a new avenue for understanding the evolution, function, and physiology of long extinct organisms. This resulted in the establishment of paleohistology as a subdiscipline of vertebrate paleontology, which has contributed greatly to our current understanding of dinosaurs as living organisms. Dinosaurs are part of a larger group of reptiles, the Archosauria, of which there are only two surviving lineages, crocodilians and birds. The goal of this review is to document progress in the field of archosaur paleohistology, focusing in particular on the Dinosauria. We briefly review the "growth age" of dinosaur histology, which has encompassed new and varied directions since its emergence in the 1950s, resulting in a shift in the scientific perception of non-avian dinosaurs from "sluggish" reptiles to fast-growing animals with relatively high metabolic rates. However, fundamental changes in growth occurred within the sister clade Aves, and we discuss this major evolutionary transition as elucidated by histology. We then review recent innovations in the field, demonstrating how paleohistology has changed and expanded to address a diversity of non-growth related questions. For example, dinosaur skull histology has elucidated the formation of curious cranial tissues (e.g., "metaplastic" tissues), and helped to clarify the evolution and function of oral adaptations, such as the dental batteries of duck-billed dinosaurs. Lastly, we discuss the development of novel techniques with which to investigate not only the skeletal tissues of dinosaurs, but also less-studied soft-tissues, through molecular paleontology and paleohistochemistry-recently developed branches of paleohistology-and the future potential of these methods to further explore fossilized tissues. We suggest that the combination of histological and molecular methods holds great potential for examining the preserved tissues of dinosaurs, basal birds, and their extant relatives. This review demonstrates the importance of traditional bone paleohistology, but also highlights the need for innovation and new analytical directions to improve and broaden the utility of paleohistology, in the pursuit of more diverse, highly specific, and sensitive methods with which to further investigate important paleontological questions.

@article{doi107717peerj7764,
    author = "Bailleul, Alida M. and O’Connor, Jingmai K. and Schweitzer, Mary H.",
    title = "Dinosaur paleohistology: review, trends and new avenues of investigation",
    year = "2019",
    journal = "PeerJ",
    abstract = {In the mid-19th century, the discovery that bone microstructure in fossils could be preserved with fidelity provided a new avenue for understanding the evolution, function, and physiology of long extinct organisms. This resulted in the establishment of paleohistology as a subdiscipline of vertebrate paleontology, which has contributed greatly to our current understanding of dinosaurs as living organisms. Dinosaurs are part of a larger group of reptiles, the Archosauria, of which there are only two surviving lineages, crocodilians and birds. The goal of this review is to document progress in the field of archosaur paleohistology, focusing in particular on the Dinosauria. We briefly review the "growth age" of dinosaur histology, which has encompassed new and varied directions since its emergence in the 1950s, resulting in a shift in the scientific perception of non-avian dinosaurs from "sluggish" reptiles to fast-growing animals with relatively high metabolic rates. However, fundamental changes in growth occurred within the sister clade Aves, and we discuss this major evolutionary transition as elucidated by histology. We then review recent innovations in the field, demonstrating how paleohistology has changed and expanded to address a diversity of non-growth related questions. For example, dinosaur skull histology has elucidated the formation of curious cranial tissues (e.g., "metaplastic" tissues), and helped to clarify the evolution and function of oral adaptations, such as the dental batteries of duck-billed dinosaurs. Lastly, we discuss the development of novel techniques with which to investigate not only the skeletal tissues of dinosaurs, but also less-studied soft-tissues, through molecular paleontology and paleohistochemistry-recently developed branches of paleohistology-and the future potential of these methods to further explore fossilized tissues. We suggest that the combination of histological and molecular methods holds great potential for examining the preserved tissues of dinosaurs, basal birds, and their extant relatives. This review demonstrates the importance of traditional bone paleohistology, but also highlights the need for innovation and new analytical directions to improve and broaden the utility of paleohistology, in the pursuit of more diverse, highly specific, and sensitive methods with which to further investigate important paleontological questions.},
    url = "https://doi.org/10.7717/peerj.7764",
    doi = "10.7717/peerj.7764",
    openalex = "W2975364321",
    references = "doi101002jmor10372, doi101017pab201519, doi101029sc005p0175, doi101038362709a0, doi101038nature01420, doi101038s4146701909259x, doi1010719781486300679, doi101093sysbiosyw033, doi101098rsbl20090310, doi101098rspb20042813, doi1011111475475400064, doi101111j1469185x201000142x, doi101111j1474919x1968tb00058x, doi101126science26251422020, doi101242dev1172409, doi101371journalpone0029958, doi101371journalpone0088834, doi1016660094837320040300253chopom20co2, doi1016660094837320050310291teafot20co2, doi1016690883135120030180286rpoumt20co2, doi1016710272463420000200115lbhoth20co2, doi1031610680390210, doi10560219780801881206, doi107717peerj4129, garilli2009first"
}

@article{zhao2019ontogenetic,
    author = "Zhao, Qi and Benton, Michael and Hayashi, Shoji and Xu, Xing",
    title = "Ontogenetic stages of ceratopsian dinosaur Psittacosaurus in bone histology",
    year = "2019",
    journal = "Acta Palaeontologica Polonica",
    url = "https://doi.org/10.4202/app.00559.2018",
    doi = "10.4202/app.00559.2018",
    openalex = "W2928806380",
    volume = "64"
}

@incollection{agotegaray2020anatomy,
    author = "Agotegaray, Mariela",
    title = "Anatomy, Histology and Physiology of Bone",
    year = "2020",
    booktitle = "SpringerBriefs in Applied Sciences and Technology",
    url = "https://doi.org/10.1007/978-3-030-64130-6\_2",
    doi = "10.1007/978-3-030-64130-6\_2",
    openalex = "W3119892905",
    pages = "7-23",
    references = "doi101002med20224, doi101038s4158601804827"
}

Bone histology has provided valuable information on the life history of dinosaurs, and the presence of growth lines provides useful information for age estimation, growth variation, and the reconstruction of paleobehavior. Here, we present new data recovered from five individuals of the non-iguanodontian ornithopod dinosaur Jeholosaurus shangyuanensis from the Early Cretaceous Jehol Biota. These specimens, ranging in body length from 16 to 62 cm, represent early juvenile, late juvenile, and subadult ontogenetic stages. The bones of Jeholosaurus mainly consist of fibrolamellar tissue, which is similar to that of other non-iguanodontian ornithopods; however, parallel-fibered bone and lamellar bone tissues were also deposited in early juvenile through subadult individuals, suggesting relatively slow growth rates. Parallel-fibered bone is only regionally present in the juvenile but is well developed throughout the outermost cortex of the subadult. Skeletochronology indicates that these specimens range in age from one to five years old. Analyzing bone tissue distribution and lines of arrested growth (LAGs) in these specimens, we estimate that Jeholosaurus reached sexual maturity at two to four years old. The largest individual (IVPP V15939) displays an apparently higher growth rate during the first two years, which is abruptly reduced in the following years, suggesting a distinct growth pattern that may be related to sexual dimorphism or variable environmental conditions. Finally, the largest specimen displays parallel-fibered bone tissue but lacks an external fundamental system (EFS) near the periphery, suggesting that it was still growing but was approaching somatic maturity at death.

@article{doi1010800272463420201768538,
    author = "Han, Fenglu and Zhao, Qi and Stiegler, Josef and Xu, Xing",
    title = "Bone histology of the non-iguanodontian ornithopod Jeholosaurus shangyuanensis and its implications for dinosaur skeletochronology and development",
    year = "2020",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "Bone histology has provided valuable information on the life history of dinosaurs, and the presence of growth lines provides useful information for age estimation, growth variation, and the reconstruction of paleobehavior. Here, we present new data recovered from five individuals of the non-iguanodontian ornithopod dinosaur Jeholosaurus shangyuanensis from the Early Cretaceous Jehol Biota. These specimens, ranging in body length from 16 to 62 cm, represent early juvenile, late juvenile, and subadult ontogenetic stages. The bones of Jeholosaurus mainly consist of fibrolamellar tissue, which is similar to that of other non-iguanodontian ornithopods; however, parallel-fibered bone and lamellar bone tissues were also deposited in early juvenile through subadult individuals, suggesting relatively slow growth rates. Parallel-fibered bone is only regionally present in the juvenile but is well developed throughout the outermost cortex of the subadult. Skeletochronology indicates that these specimens range in age from one to five years old. Analyzing bone tissue distribution and lines of arrested growth (LAGs) in these specimens, we estimate that Jeholosaurus reached sexual maturity at two to four years old. The largest individual (IVPP V15939) displays an apparently higher growth rate during the first two years, which is abruptly reduced in the following years, suggesting a distinct growth pattern that may be related to sexual dimorphism or variable environmental conditions. Finally, the largest specimen displays parallel-fibered bone tissue but lacks an external fundamental system (EFS) near the periphery, suggesting that it was still growing but was approaching somatic maturity at death.",
    url = "https://doi.org/10.1080/02724634.2020.1768538",
    doi = "10.1080/02724634.2020.1768538",
    openalex = "W3048383165",
    references = "doi101002ar20991, doi101038s4146701909259x, doi1021037jtd202924, zhao2019ontogenetic"
}

The fossil record of Mesozoic tetrapods in Bulgaria is sparse and currently limited to the Maastrichtian limestones of the Kajlka Formation. Herein we report on two bone fragments from the Upper Cretaceous, lower Santonian to/or lower Campanian, coal-bearing sedimentary succession of the Western Srednogorie, Western Bulgaria. Due to being very fragmentary in nature, it is not possible to assess their taxonomy based solely on osteological characters and a paleohistological analysis is used as an alternative method for taxonomic identification. Our analysis reveals an informative combination of histological characteristics, most notably: absence of free medullar cavity, thick cortex affected by extreme Haversian remodeling with up to five generations of secondary osteons, and laminar bone in the mid-cortex characterized by moderately to highly organized bone matrix. These results do allow us to tentatively assign the studied fossils to a titanosaurian sauropod. The interpretation of the new Bulgarian material as belonging to Titanosauria is intriguing, because it comes from a time interval when sauropods are rare or completely absent in the fossil record of Europe. The histologically assessed ontogenetic stage for one of the fragments suggests that it may come from a sexually mature animal.

@article{doi1026879879,
    author = "Nikolov, Vladimir and Yaneva, Marlena and Dochev, Docho and Konyovska, Ralitsa and Sergeeva, Ivanina and Hristova, Latinka",
    title = "Bone histology reveals the first record of titanosaur (Dinosauria: Sauropoda) from the Late Cretaceous of Bulgaria",
    year = "2020",
    journal = "Palaeontologia Electronica",
    abstract = "The fossil record of Mesozoic tetrapods in Bulgaria is sparse and currently limited to the Maastrichtian limestones of the Kajlka Formation. Herein we report on two bone fragments from the Upper Cretaceous, lower Santonian to/or lower Campanian, coal-bearing sedimentary succession of the Western Srednogorie, Western Bulgaria. Due to being very fragmentary in nature, it is not possible to assess their taxonomy based solely on osteological characters and a paleohistological analysis is used as an alternative method for taxonomic identification. Our analysis reveals an informative combination of histological characteristics, most notably: absence of free medullar cavity, thick cortex affected by extreme Haversian remodeling with up to five generations of secondary osteons, and laminar bone in the mid-cortex characterized by moderately to highly organized bone matrix. These results do allow us to tentatively assign the studied fossils to a titanosaurian sauropod. The interpretation of the new Bulgarian material as belonging to Titanosauria is intriguing, because it comes from a time interval when sauropods are rare or completely absent in the fossil record of Europe. The histologically assessed ontogenetic stage for one of the fragments suggests that it may come from a sexually mature animal.",
    url = "https://doi.org/10.26879/879",
    doi = "10.26879/879",
    openalex = "W3011167926",
    references = "garilli2009first"
}

@incollection{cubo2021bone,
    author = "Cubo, Jorge and Huttenlocker, Adam and Legendre, Lucas J. and Olivier, Chloé and de Ricqlès, Armand",
    title = "Bone Histology and Thermal Physiology",
    year = "2021",
    booktitle = "Vertebrate Skeletal Histology and Paleohistology",
    url = "https://doi.org/10.1201/9781351189590-37",
    doi = "10.1201/9781351189590-37",
    openalex = "W3168197743",
    pages = "757-773"
}

The early ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia, Russia, is one of the most advanced and largest (up to 2.5 m) members of the genus. Here we present a description of ontogenetic changes in the long-bone histology of this species. Analysis of a growth series of femora demonstrates significant histological maturation during ontogeny, expressed by the progressive appearance of signs of bone remodeling (erosion bays, secondary bone formation), decreasing of vascularity, changing of the orientation of vascular canals from reticular to longitudinal, and appearance of parallel-fibred bone in the outer part cortex. These ontogenetic changes in the longbone histology of P. sibiricus are generally similar to those of another relatively advanced species, P. lujiatunensis from China. The basal P. mongoliensis from Mongolia shows less mature long-bone histology during late ontogeny (e.g., the late appearance of signs of remodeling and the predominance of reticular vascularization at later stages). We suggest that the earlier achievement of histological maturity is an evolutionary trend of the genus Psittacosaurus.

@article{doi104202app008192020,
    author = "Skutschas, Pavel P. and Morozov, Semyon S. and Averianov, Alexander O. and Leshchinskiy, Sergey V. and Ivantsov, S. V. and Fayngerts, A. V. and Feofanova, Olga A. and Владимирова, О Н and Slobodin, Dmitry A.",
    title = "Femoral histology and growth patterns of the ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia",
    year = "2021",
    journal = "Acta Palaeontologica Polonica",
    abstract = "The early ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia, Russia, is one of the most advanced and largest (up to 2.5 m) members of the genus. Here we present a description of ontogenetic changes in the long-bone histology of this species. Analysis of a growth series of femora demonstrates significant histological maturation during ontogeny, expressed by the progressive appearance of signs of bone remodeling (erosion bays, secondary bone formation), decreasing of vascularity, changing of the orientation of vascular canals from reticular to longitudinal, and appearance of parallel-fibred bone in the outer part cortex. These ontogenetic changes in the longbone histology of P. sibiricus are generally similar to those of another relatively advanced species, P. lujiatunensis from China. The basal P. mongoliensis from Mongolia shows less mature long-bone histology during late ontogeny (e.g., the late appearance of signs of remodeling and the predominance of reticular vascularization at later stages). We suggest that the earlier achievement of histological maturity is an evolutionary trend of the genus Psittacosaurus.",
    url = "https://doi.org/10.4202/app.00819.2020",
    doi = "10.4202/app.00819.2020",
    openalex = "W3174475397",
    references = "zhao2019ontogenetic"
}

Abstract We present a detailed histological study of long bones from an ontogenetic series of Mussaurus patagonicus, an early sauropodomorph from the Lower Jurassic of Argentina. Twenty long bones, including humeri, femora and fibulae, obtained from 13 individuals of different body sizes were sampled for histological analysis. In general terms, the cortical bone is formed by a well vascularized fibrolamellar and parallel fibred bone. Except for the smaller individuals, cyclical growth marks (CGMs) are well recorded in all the specimens but their number and relative position is highly variable. Mussaurus exhibits marked variation regarding relative growth rate, with some individuals growing much faster than others. Such variation affects the size of the adult individuals, which results in a poor correlation between the body size and the age/ontogenetic stage for this taxon. These discrepancies may be related to sexual dimorphism and/or developmental plasticity. Intraspecific variation is also recorded with regard to the growth strategies, which can vary from cyclical, as in other early sauropodomorphs, to continuous, as reported in sauropods. Sexual maturity appears to have been reached between 23 and 31 years, which is delayed in comparison to other early sauropodomorphs but more comparable with derived sauropods. The attainment of somatic maturity appears to have been reached at about 14 years after onset of sexual maturity. Mussaurus is a sauropodiform, phylogenetically closer to sauropods than most other Early Jurassic sauropodomorphs, and therefore provides critical information for understanding palaeobiological aspects of the origin of sauropods and the onset of gigantism in this lineage.

@article{doi101111pala12614,
    author = "Cerda, Ignacio A. and Pol, Diego and Otero, Alejandro and Chinsamy, Anusuya",
    title = "Palaeobiology of the early sauropodomorph Mussaurus patagonicus inferred from its long bone histology",
    year = "2022",
    journal = "Palaeontology",
    abstract = "Abstract We present a detailed histological study of long bones from an ontogenetic series of Mussaurus patagonicus, an early sauropodomorph from the Lower Jurassic of Argentina. Twenty long bones, including humeri, femora and fibulae, obtained from 13 individuals of different body sizes were sampled for histological analysis. In general terms, the cortical bone is formed by a well vascularized fibrolamellar and parallel fibred bone. Except for the smaller individuals, cyclical growth marks (CGMs) are well recorded in all the specimens but their number and relative position is highly variable. Mussaurus exhibits marked variation regarding relative growth rate, with some individuals growing much faster than others. Such variation affects the size of the adult individuals, which results in a poor correlation between the body size and the age/ontogenetic stage for this taxon. These discrepancies may be related to sexual dimorphism and/or developmental plasticity. Intraspecific variation is also recorded with regard to the growth strategies, which can vary from cyclical, as in other early sauropodomorphs, to continuous, as reported in sauropods. Sexual maturity appears to have been reached between 23 and 31 years, which is delayed in comparison to other early sauropodomorphs but more comparable with derived sauropods. The attainment of somatic maturity appears to have been reached at about 14 years after onset of sexual maturity. Mussaurus is a sauropodiform, phylogenetically closer to sauropods than most other Early Jurassic sauropodomorphs, and therefore provides critical information for understanding palaeobiological aspects of the origin of sauropods and the onset of gigantism in this lineage.",
    url = "https://doi.org/10.1111/pala.12614",
    doi = "10.1111/pala.12614",
    openalex = "W4288518744",
    references = "doi101002ar24282, doi101098rstb20190142, lee2019a, zhao2019ontogenetic"
}

Amazing how even after half of a century some things do not change. Together again at the University of Pennsylvania, Peter Dodson and editorial co-author JL are energetically talking about six things at once, catching up as old friends are wont to do. Walking along the beautiful, tree-lined, quiet of Locust walk, topics bounce from new dinosaur finds, to what the children (and grandchildren!) are up to, to which of our body parts are the latest to stop working well (hey, we have known each other for some 50 years!). As has been the case since our days together at Yale, JL is lagging behind as Peter's energy, now as back in New Haven, has him moving ever faster than his old anatomy table mate. “C'mon, Jeff,” the august Penn Prof admonishes, “we finally get an audience with Professor Leidy, and let's not be late!” Yes, indeed. We have finally arranged a formal audience to see Professor Joseph Leidy, or, more specifically, his brain. For those of you who are not acquainted with Professor Leidy (shame, shame!), he was America's first dinosaur paleontologist of note, having reported and named (in 1858 and 1865; Leidy, 1858, 1865) the first American dinosaur, the “duck-billed” Hadrosaurus, unearthed in New Jersey (and you thought the state's only remains of note were those of Mob boss Jimmy Hoffa!). Subsequently, Leidy reconstructed Hadrosaurus at the Philadelphia Academy of Natural Sciences in 1868, the first museum display of any dinosaur. He estimated it to be 25 ft long and, based on its small forelimbs and long hind limbs, gave it a “kangaroo-like” stance with a semi-upright posture. Indeed, this vertical position became the image of dinosaurs imprinted in our collective visualization that remains to this day (see Dodson, 2009 for discussion). Leidy's day job was as the Professor of Anatomy at the University of Pennsylvania School of Medicine (the first in the United States), and he was a polymath of such renown that his biographer boldly titled his story, Joseph Leidy: The Last Man Who Knew Everything (Warren, 1999). Indeed, when the parent organization of The Anatomical Record, the American Association for Anatomy was formed in 1888 (originally named the Association of American Anatomists, today seen as an exclusionary banner, but done then to highlight specifically the emergence of American—over European—science), Professor Leidy was unanimously chosen its first President, in absentia no less. He was seen by many as the embodiment of an American scientist, the greatest of his day. There are giants and then there are GIANT giants, and our Professor Leidy falls into the latter category (Figure 1). And this brings us back to another titan of his science, and the reason for this Special Issue, JL's fast moving colleague, Peter Dodson. Like his Penn ancestor, Peter (our ties are too close for continued formalities here) is a giant among dinosaurs, not an easy feat if you think about it. His contributions to understanding the world of dinosaurs—from his paleontological findings, scholarly writings, museum exhibit creations, and birthing of superb progeny—have made him stand out in the world of dinosaur science. Indeed, Peter has given much to our own journal, being a frequent contributor (e.g., Dodson, 2003, 2009, 2020; Hedrick et al., 2020, 2022; Schachner et al., 2009, 2011; Tumanova et al., 2023), and Guest Editing two of the most popular Special Issues in our history, “Unearthing the Anatomy of Dinosaurs: New Insights into their Functional Morphology and Paleobiology” (Dodson, 2009; Laitman, 2009; Laitman & Albertine, 2009) and “The Hidden World of Dinosaurs” (Hedrick & Dodson, 2020; Laitman & Albertine, 2020; Figure 2). The 2009 Special Issue, our first on dinosaurs, was so much in demand that our Publisher, Wiley, had to print additional copies for individual sale (Dodson Dinos make money, at least for Wiley!) Beyond the quality of his science, Peter has been given a gift that he has shared with those of us fortunate to be his student, mentee, or colleague: his boundless goodness and caring. This “Dodsoness” quality has spanned his career and has touched many. Indeed, editorial co-author JL has written previously on how Peter's kindness helped him as an insecure and shy (no comments out there, please!). Yale graduate student to survive his overwhelming fears at the onset of his own path (see Laitman, 2017). More to our point here is how his own dinosaur-philic graduate students and mentees have grown and prospered in significant part due to his loving guidance. This current special, Special Issue, “Dinosaurs: New Ideas from Old Bones” (Fiorillo et al., 2023) has been meticulously Guest-edited by three who have learned their craft upon poppa Dodson's knee as his graduate students: Anthony Fiorillo, Executive Director of the New Mexico Museum of Natural History and Science; Catherine Forster, Professor of Geology and of Biology at George Washington University; and David Weishampel, Professor of Functional Anatomy and Evolution at Johns Hopkins University. These three have themselves had extraordinary careers in the multifaceted world of dinosaur paleontology and biology, and have been referred to as “the Big Three” of PD's students (by Catherine; oy!, I can hear the growls from other PD progeny!). As we write this, Tony is likely thoroughly enjoying the warmth of New Mexico, having spent a good part of his career studying arctic dinosaurs (equally cold is that, sadly, he never achieved his childhood dream of playing center field for the New York Yankees; hey, Tony, they have not won a World Series since 2009 so you still might have a chance!); Catherine, Tony's graduate student office mate at Penn (she helped him in his dissertation field-work and he repaid her kindness by being her occasional dog-sitter), followed directly Poppa Dodson's love by embracing horned dinosaurs for much of her prolific career; and Dave, Peter's first graduate student gaining his PhD in 1981, and thus placing him as the “first” among all PD progeny (all others always compare themselves to one's first student—and usually wince when their name is mentioned!) has had a marvelous path, within which he authored what many consider the definitive work on dinosaurs, the Dinosauria (Weishampel et al., 2007), and was even a consultant for his friend Steven Spielberg's Jurassic Park series (wonder if he got free tickets to the movies?). While this extraordinarily successful trio have known each other since the Cretaceous, this is the first time they have come together on a major project. HS and JL get a big smile out of the fact that our journal has served as a vehicle for this historic marriage (Figure 3). As one will see from the issue, many of the best and brightest in the field responded eagerly to contribute to a volume honoring Peter. Indeed, while this Special Issue focuses on new findings in dinosaur biology, a recent mammoth, sister Special Issue on crocodiles, “The Age of Crocodilians and Their Kin: Anatomy, Physiology, and Evolution,” Guest Edited by Casey Holliday (an academic “grandson” of Peter) of the University of Missouri School of Medicine and Emma R. Schachner (another PhD student of Peter) then of Louisiana State University Health Sciences Center (Holliday & Schachner, 2022; Laitman & Smith, 2022), was also done largely as an homage to Peter. Just the mention of something that will say a “thanks” to Peter has colleagues and former students and grand-students coming out of the rock pile to contribute. Attesting to Peter's broad influence, the contributions do not focus solely upon his own particular interests/scholarship charting the rise and distribution of ceratopsian dinosaurs (he is their undisputed horned king!). Rather, to name just some, they span a glorious gamut: from detailed descriptions of unusual Therapods from New Jersey (really? hadrosaurs, Jimmy Hoffa…who knew Jersey was actually interesting; sorry, JL is a native New Yorker and has little control when commenting on New Jersey; Gallagher, 2023); reports on a new iguanodontian dinosaur from South Africa (Forster et al., 2023); new insights on evolutionary relationships from analyses of the hyolaryngeal apparatus in extant archosaurs (i.e., birds and crocodilians; Yoshida et al., 2023); new reconstructions of the pectoral girdle and forelimb musculature of Megaraptora (Rolando et al., 2023); insights from osteohistology of Dromornis stironi with implications for understanding the histology of Australian mihirung birds (Chinsamy et al., 2023); insightful observations on fracture and disease in a large-bodied ornithomimosaur with insights into identifying unusual endosteal bone in the fossil record (Chinzorig et al., 2023); a comprehensive assessment of the history and future of the study of morphometrics in the study on non-avian dinosaurs (Hedrick, 2023); detailed modeling to assess and predict the abundance of large carnivorous dinosaurs of the Upper Jurassic Morrison Formation and the Upper Cretaceous Dinosaur Park formation (by Peter and JL's Yale classmate, the ever-creative James Farlow; JL is still in awe at all the super-bright dino dudes that surrounded him at Yale “back in the day”; Farlow et al., 2023); to a number of papers—naturally—on Peter's great love, the ceratopsians, including those by lead Guest Editor Fiorillo (Fiorillo & Tykoski, 2023) and Peter's successor teaching anatomy at Penn, Ali Nabavizadeh (Nabavizadeh, 2023). Even the cover of this Special Issue has been a creative homage to Peter, lovingly created by Anatomical Record Associate Editor (and artist extraordinaire) Adam Hartstone-Rose (Hartstone-Rose et al., 2023). What an incredible smorgasbord of new ideas from the minds of some of today's best dinosaur workers. “Hurry up, Jeff,” Peter exhorts, “our appointment is for 10:00 sharp and the curator is expecting us.” Along with JL's accommodating wife Leila (who was pressed into service as our photographer; if it was not for her adoring Peter—who does not?—not a chance she would spend hours taking photos of poor JL!), we bundled into our Uber and headed to the glorious Mütter Museum and Professor Leidy. The first time Peter and JL tried to visit Professor Leidy was back in 2009 when he was then in residence at the Wistar Institute on Penn's campus (they were turned away as they did not have an appropriate appointment and told “the Professor did not receive just anyone”). Since then, Leidy's domicile has changed (fortunately) to the extraordinary Mütter Museum, named after surgeon Thomas Dent Mütter who in 1856 donated his extensive collections of anatomical and pathological specimens to the College of Physicians of Philadelphia, wherein they have both grown and been lovingly cared for (btw, this is a really cool place, and if you had to choose between some cracked Liberty Bell and the Mütter, go Mütter!; see Worden, 2002). For Peter and JL, visiting Professor Leidy was almost a religious experience, as the Professor was their direct ancestor in so many ways: For PD, as Professor of Anatomy at Penn Veterinary School, and the comparative anatomist and vertebrate paleontologist at Penn, the line is direct; for JL, also, as an anatomy professor and fossil aficionado, but also as a past President of the American Association for Anatomy, the society of which Leidy was the first President, the bond is also powerful. Both PD and JL were well aware that they were coming into the presence of both their past and present (Figure 4). Professor Leidy was brought to PD and JL in his permanent home, a thick and heavy glass jar. What remained of the Professor was his brain. While this may seem odd, it was not uncommon in the 19th century to preserve the brains of great people (when JL told his daughter of this custom, Miss Snarky responded “do not worry, dad, you are safe”). The Professor's brain had turned a rather eerie shade of green, probably due to the preservatives used. Green or not, encased or not, this extraordinary anatomical remain was the repository of arguably more scientific knowledge than was held by any other mortal in the latter half of the 19th century. Within lay the secrets of anatomy and the founding of dinosaur paleontology in the United States. Peter and JL were in the presence of greatness, a most special and rare moment. As the group left the Mütter that day—and headed to our next stop, Peter's second home, his beloved Philadelphia Academy of Natural Sciences—JL could not stop pondering the gravity of the encounter. There were two of the rarest gems in the history of American Paleontology, Professors Joseph Leidy and Peter Dodson, together. As JL's kids would say, “two heavy dudes.” As Peter, JL, and JL's wife Leila (our sometimes complaining photographer) came into the main hall of the Academy staring us in the face were exhibit after exhibit that Peter had lovingly created. His name and images were everywhere. One, in particular, caught JL's attention as it so accurately summarized the moment and the person of appreciation: there was a picture of Peter with his reconstruction of Avaceratops with a bold banner that read “A Rare Find” (Figure 5). It clearly identified both the fossil and the scientist. HS and JL are very proud, on behalf of The Anatomical Record, to share both the wonderful science and scientists that have come together to offer new ideas from old bones, and to give a heartfelt thanks to our “Rare Find” of a colleague, Peter Dodson. We hope that you will explore the articles within and enjoy and learn from them as much as we have. And give a smile and thanks when you think of our most dear colleague, Peter Dodson. Jeffrey T. Laitman: Conceptualization; writing – original draft; writing – review and editing; visualization. Heather F. Smith: Conceptualization; writing – original draft; writing – review and editing; visualization.

@article{doi101002ar25233,
    author = "Laitman, Jeffrey T. and Smith, Heather F.",
    title = "Dinosaurs of all ilks bow and pay tribute to Peter Dodson, their intrepid chronicler, in an Anatomical Record Special Issue in his honor",
    year = "2023",
    journal = "The Anatomical Record",
    abstract = "Amazing how even after half of a century some things do not change. Together again at the University of Pennsylvania, Peter Dodson and editorial co-author JL are energetically talking about six things at once, catching up as old friends are wont to do. Walking along the beautiful, tree-lined, quiet of Locust walk, topics bounce from new dinosaur finds, to what the children (and grandchildren!) are up to, to which of our body parts are the latest to stop working well (hey, we have known each other for some 50 years!). As has been the case since our days together at Yale, JL is lagging behind as Peter's energy, now as back in New Haven, has him moving ever faster than his old anatomy table mate. “C'mon, Jeff,” the august Penn Prof admonishes, “we finally get an audience with Professor Leidy, and let's not be late!” Yes, indeed. We have finally arranged a formal audience to see Professor Joseph Leidy, or, more specifically, his brain. For those of you who are not acquainted with Professor Leidy (shame, shame!), he was America's first dinosaur paleontologist of note, having reported and named (in 1858 and 1865; Leidy, 1858, 1865) the first American dinosaur, the “duck-billed” Hadrosaurus, unearthed in New Jersey (and you thought the state's only remains of note were those of Mob boss Jimmy Hoffa!). Subsequently, Leidy reconstructed Hadrosaurus at the Philadelphia Academy of Natural Sciences in 1868, the first museum display of any dinosaur. He estimated it to be 25 ft long and, based on its small forelimbs and long hind limbs, gave it a “kangaroo-like” stance with a semi-upright posture. Indeed, this vertical position became the image of dinosaurs imprinted in our collective visualization that remains to this day (see Dodson, 2009 for discussion). Leidy's day job was as the Professor of Anatomy at the University of Pennsylvania School of Medicine (the first in the United States), and he was a polymath of such renown that his biographer boldly titled his story, Joseph Leidy: The Last Man Who Knew Everything (Warren, 1999). Indeed, when the parent organization of The Anatomical Record, the American Association for Anatomy was formed in 1888 (originally named the Association of American Anatomists, today seen as an exclusionary banner, but done then to highlight specifically the emergence of American—over European—science), Professor Leidy was unanimously chosen its first President, in absentia no less. He was seen by many as the embodiment of an American scientist, the greatest of his day. There are giants and then there are GIANT giants, and our Professor Leidy falls into the latter category (Figure 1). And this brings us back to another titan of his science, and the reason for this Special Issue, JL's fast moving colleague, Peter Dodson. Like his Penn ancestor, Peter (our ties are too close for continued formalities here) is a giant among dinosaurs, not an easy feat if you think about it. His contributions to understanding the world of dinosaurs—from his paleontological findings, scholarly writings, museum exhibit creations, and birthing of superb progeny—have made him stand out in the world of dinosaur science. Indeed, Peter has given much to our own journal, being a frequent contributor (e.g., Dodson, 2003, 2009, 2020; Hedrick et al., 2020, 2022; Schachner et al., 2009, 2011; Tumanova et al., 2023), and Guest Editing two of the most popular Special Issues in our history, “Unearthing the Anatomy of Dinosaurs: New Insights into their Functional Morphology and Paleobiology” (Dodson, 2009; Laitman, 2009; Laitman \& Albertine, 2009) and “The Hidden World of Dinosaurs” (Hedrick \& Dodson, 2020; Laitman \& Albertine, 2020; Figure 2). The 2009 Special Issue, our first on dinosaurs, was so much in demand that our Publisher, Wiley, had to print additional copies for individual sale (Dodson Dinos make money, at least for Wiley!) Beyond the quality of his science, Peter has been given a gift that he has shared with those of us fortunate to be his student, mentee, or colleague: his boundless goodness and caring. This “Dodsoness” quality has spanned his career and has touched many. Indeed, editorial co-author JL has written previously on how Peter's kindness helped him as an insecure and shy (no comments out there, please!). Yale graduate student to survive his overwhelming fears at the onset of his own path (see Laitman, 2017). More to our point here is how his own dinosaur-philic graduate students and mentees have grown and prospered in significant part due to his loving guidance. This current special, Special Issue, “Dinosaurs: New Ideas from Old Bones” (Fiorillo et al., 2023) has been meticulously Guest-edited by three who have learned their craft upon poppa Dodson's knee as his graduate students: Anthony Fiorillo, Executive Director of the New Mexico Museum of Natural History and Science; Catherine Forster, Professor of Geology and of Biology at George Washington University; and David Weishampel, Professor of Functional Anatomy and Evolution at Johns Hopkins University. These three have themselves had extraordinary careers in the multifaceted world of dinosaur paleontology and biology, and have been referred to as “the Big Three” of PD's students (by Catherine; oy!, I can hear the growls from other PD progeny!). As we write this, Tony is likely thoroughly enjoying the warmth of New Mexico, having spent a good part of his career studying arctic dinosaurs (equally cold is that, sadly, he never achieved his childhood dream of playing center field for the New York Yankees; hey, Tony, they have not won a World Series since 2009 so you still might have a chance!); Catherine, Tony's graduate student office mate at Penn (she helped him in his dissertation field-work and he repaid her kindness by being her occasional dog-sitter), followed directly Poppa Dodson's love by embracing horned dinosaurs for much of her prolific career; and Dave, Peter's first graduate student gaining his PhD in 1981, and thus placing him as the “first” among all PD progeny (all others always compare themselves to one's first student—and usually wince when their name is mentioned!) has had a marvelous path, within which he authored what many consider the definitive work on dinosaurs, the Dinosauria (Weishampel et al., 2007), and was even a consultant for his friend Steven Spielberg's Jurassic Park series (wonder if he got free tickets to the movies?). While this extraordinarily successful trio have known each other since the Cretaceous, this is the first time they have come together on a major project. HS and JL get a big smile out of the fact that our journal has served as a vehicle for this historic marriage (Figure 3). As one will see from the issue, many of the best and brightest in the field responded eagerly to contribute to a volume honoring Peter. Indeed, while this Special Issue focuses on new findings in dinosaur biology, a recent mammoth, sister Special Issue on crocodiles, “The Age of Crocodilians and Their Kin: Anatomy, Physiology, and Evolution,” Guest Edited by Casey Holliday (an academic “grandson” of Peter) of the University of Missouri School of Medicine and Emma R. Schachner (another PhD student of Peter) then of Louisiana State University Health Sciences Center (Holliday \& Schachner, 2022; Laitman \& Smith, 2022), was also done largely as an homage to Peter. Just the mention of something that will say a “thanks” to Peter has colleagues and former students and grand-students coming out of the rock pile to contribute. Attesting to Peter's broad influence, the contributions do not focus solely upon his own particular interests/scholarship charting the rise and distribution of ceratopsian dinosaurs (he is their undisputed horned king!). Rather, to name just some, they span a glorious gamut: from detailed descriptions of unusual Therapods from New Jersey (really? hadrosaurs, Jimmy Hoffa…who knew Jersey was actually interesting; sorry, JL is a native New Yorker and has little control when commenting on New Jersey; Gallagher, 2023); reports on a new iguanodontian dinosaur from South Africa (Forster et al., 2023); new insights on evolutionary relationships from analyses of the hyolaryngeal apparatus in extant archosaurs (i.e., birds and crocodilians; Yoshida et al., 2023); new reconstructions of the pectoral girdle and forelimb musculature of Megaraptora (Rolando et al., 2023); insights from osteohistology of Dromornis stironi with implications for understanding the histology of Australian mihirung birds (Chinsamy et al., 2023); insightful observations on fracture and disease in a large-bodied ornithomimosaur with insights into identifying unusual endosteal bone in the fossil record (Chinzorig et al., 2023); a comprehensive assessment of the history and future of the study of morphometrics in the study on non-avian dinosaurs (Hedrick, 2023); detailed modeling to assess and predict the abundance of large carnivorous dinosaurs of the Upper Jurassic Morrison Formation and the Upper Cretaceous Dinosaur Park formation (by Peter and JL's Yale classmate, the ever-creative James Farlow; JL is still in awe at all the super-bright dino dudes that surrounded him at Yale “back in the day”; Farlow et al., 2023); to a number of papers—naturally—on Peter's great love, the ceratopsians, including those by lead Guest Editor Fiorillo (Fiorillo \& Tykoski, 2023) and Peter's successor teaching anatomy at Penn, Ali Nabavizadeh (Nabavizadeh, 2023). Even the cover of this Special Issue has been a creative homage to Peter, lovingly created by Anatomical Record Associate Editor (and artist extraordinaire) Adam Hartstone-Rose (Hartstone-Rose et al., 2023). What an incredible smorgasbord of new ideas from the minds of some of today's best dinosaur workers. “Hurry up, Jeff,” Peter exhorts, “our appointment is for 10:00 sharp and the curator is expecting us.” Along with JL's accommodating wife Leila (who was pressed into service as our photographer; if it was not for her adoring Peter—who does not?—not a chance she would spend hours taking photos of poor JL!), we bundled into our Uber and headed to the glorious Mütter Museum and Professor Leidy. The first time Peter and JL tried to visit Professor Leidy was back in 2009 when he was then in residence at the Wistar Institute on Penn's campus (they were turned away as they did not have an appropriate appointment and told “the Professor did not receive just anyone”). Since then, Leidy's domicile has changed (fortunately) to the extraordinary Mütter Museum, named after surgeon Thomas Dent Mütter who in 1856 donated his extensive collections of anatomical and pathological specimens to the College of Physicians of Philadelphia, wherein they have both grown and been lovingly cared for (btw, this is a really cool place, and if you had to choose between some cracked Liberty Bell and the Mütter, go Mütter!; see Worden, 2002). For Peter and JL, visiting Professor Leidy was almost a religious experience, as the Professor was their direct ancestor in so many ways: For PD, as Professor of Anatomy at Penn Veterinary School, and the comparative anatomist and vertebrate paleontologist at Penn, the line is direct; for JL, also, as an anatomy professor and fossil aficionado, but also as a past President of the American Association for Anatomy, the society of which Leidy was the first President, the bond is also powerful. Both PD and JL were well aware that they were coming into the presence of both their past and present (Figure 4). Professor Leidy was brought to PD and JL in his permanent home, a thick and heavy glass jar. What remained of the Professor was his brain. While this may seem odd, it was not uncommon in the 19th century to preserve the brains of great people (when JL told his daughter of this custom, Miss Snarky responded “do not worry, dad, you are safe”). The Professor's brain had turned a rather eerie shade of green, probably due to the preservatives used. Green or not, encased or not, this extraordinary anatomical remain was the repository of arguably more scientific knowledge than was held by any other mortal in the latter half of the 19th century. Within lay the secrets of anatomy and the founding of dinosaur paleontology in the United States. Peter and JL were in the presence of greatness, a most special and rare moment. As the group left the Mütter that day—and headed to our next stop, Peter's second home, his beloved Philadelphia Academy of Natural Sciences—JL could not stop pondering the gravity of the encounter. There were two of the rarest gems in the history of American Paleontology, Professors Joseph Leidy and Peter Dodson, together. As JL's kids would say, “two heavy dudes.” As Peter, JL, and JL's wife Leila (our sometimes complaining photographer) came into the main hall of the Academy staring us in the face were exhibit after exhibit that Peter had lovingly created. His name and images were everywhere. One, in particular, caught JL's attention as it so accurately summarized the moment and the person of appreciation: there was a picture of Peter with his reconstruction of Avaceratops with a bold banner that read “A Rare Find” (Figure 5). It clearly identified both the fossil and the scientist. HS and JL are very proud, on behalf of The Anatomical Record, to share both the wonderful science and scientists that have come together to offer new ideas from old bones, and to give a heartfelt thanks to our “Rare Find” of a colleague, Peter Dodson. We hope that you will explore the articles within and enjoy and learn from them as much as we have. And give a smile and thanks when you think of our most dear colleague, Peter Dodson. Jeffrey T. Laitman: Conceptualization; writing – original draft; writing – review and editing; visualization. Heather F. Smith: Conceptualization; writing – original draft; writing – review and editing; visualization.",
    url = "https://doi.org/10.1002/ar.25233",
    doi = "10.1002/ar.25233",
    openalex = "W4375844442",
    references = "doi101002ar20989, doi101002ar21439, doi101002ar24099, doi101002ar25038, doi101002ar25047, doi101002ar25069, doi101002ar25104, doi101002ar25128, doi101002ar25196, doi101002ar25205, doi101002ar25241, farlow2023dragons"
}

Studies on pathological fossil bones have allowed improving the knowledge of physiology and ecology, and consequently the life history of extinct organisms. Among extinct vertebrates, non-avian dinosaurs have drawn attention in terms of pathological evidence, since a wide array of fossilized lesions and diseases were noticed in these ancient organisms. Here, we evaluate the pathological conditions observed in individuals of different brachyrostran (Theropoda, Abelisauridae) taxa, including Aucasaurus garridoi, Elemgasem nubilus, and Quilmesaurus curriei. For this, we use multiple methodological approaches such as histology and computed tomography, in addition to the macroscopic evaluation. The holotype of Aucasaurus shows several pathognomonic traits of a failure of the vertebral segmentation during development, causing the presence of two fused caudal vertebrae. The occurrence of this condition in Aucasaurus is the first case to be documented so far in non-tetanuran theropods. Regarding the holotype of Elemgasem, the histology of two fused vertebrae shows an intervertebral space between the centra, thus the fusion is limited to the distal rim of the articular surfaces. This pathology is here considered as spondyloarthropathy, the first evidence for a non-tetanuran theropod. The microstructural arrangement of the right tibia of Quilmesaurus shows a marked variation in a portion of the outer cortex, probably due to the presence of the radial fibrolamellar bone tissue. Although similar bone tissue is present in other extinct vertebrates and the cause of its formation is still debated, it could be a response to some kind of pathology. Among non-avian theropods, traumatic injuries are better represented than other maladies (e.g., infection, congenital or metabolic diseases, etc.). These pathologies are recovered mainly among large-sized theropods such as Abelisauridae, Allosauridae, Carcharodontosauridae, and Tyrannosauridae, and distributed principally among axial elements. Statistical tests on the distribution of injuries in these theropod clades show a strong association between taxa-pathologies, body regions-pathologies, and taxa-body regions, suggesting different life styles and behaviours may underlie the frequency of different injuries among theropod taxa.

@article{doi101186s1286202302187x,
    author = "Baiano, Mattia A. and Cerda, Ignacio A. and Bertozzo, Filippo and Pol, Diego",
    title = "New information on paleopathologies in non-avian theropod dinosaurs: a case study on South American abelisaurids",
    year = "2024",
    journal = "BMC Ecology and Evolution",
    abstract = "Studies on pathological fossil bones have allowed improving the knowledge of physiology and ecology, and consequently the life history of extinct organisms. Among extinct vertebrates, non-avian dinosaurs have drawn attention in terms of pathological evidence, since a wide array of fossilized lesions and diseases were noticed in these ancient organisms. Here, we evaluate the pathological conditions observed in individuals of different brachyrostran (Theropoda, Abelisauridae) taxa, including Aucasaurus garridoi, Elemgasem nubilus, and Quilmesaurus curriei. For this, we use multiple methodological approaches such as histology and computed tomography, in addition to the macroscopic evaluation. The holotype of Aucasaurus shows several pathognomonic traits of a failure of the vertebral segmentation during development, causing the presence of two fused caudal vertebrae. The occurrence of this condition in Aucasaurus is the first case to be documented so far in non-tetanuran theropods. Regarding the holotype of Elemgasem, the histology of two fused vertebrae shows an intervertebral space between the centra, thus the fusion is limited to the distal rim of the articular surfaces. This pathology is here considered as spondyloarthropathy, the first evidence for a non-tetanuran theropod. The microstructural arrangement of the right tibia of Quilmesaurus shows a marked variation in a portion of the outer cortex, probably due to the presence of the radial fibrolamellar bone tissue. Although similar bone tissue is present in other extinct vertebrates and the cause of its formation is still debated, it could be a response to some kind of pathology. Among non-avian theropods, traumatic injuries are better represented than other maladies (e.g., infection, congenital or metabolic diseases, etc.). These pathologies are recovered mainly among large-sized theropods such as Abelisauridae, Allosauridae, Carcharodontosauridae, and Tyrannosauridae, and distributed principally among axial elements. Statistical tests on the distribution of injuries in these theropod clades show a strong association between taxa-pathologies, body regions-pathologies, and taxa-body regions, suggesting different life styles and behaviours may underlie the frequency of different injuries among theropod taxa.",
    url = "https://doi.org/10.1186/s12862-023-02187-x",
    doi = "10.1186/s12862-023-02187-x",
    openalex = "W4392788624",
    references = "doi101098rsbl20220404, doi101111joa13363, doi101126scienceadc8714, zhao2019ontogenetic"
}

from Canada were sampled for comparison. The results of the sampling indicate a common osteohistology with the European specimens. A broad histological comparison is provided to reject alternative taxonomic affinities aside from ichthyosaurs of the very large bone segment. Most importantly, we highlight the occurrence of shared peculiar osteogenic processes in Late Triassic giant ichthyosaurs, reflecting special ossification strategies enabling fast growth and achievement of giant size and/or related to biomechanical properties akin to ossified tendons.

@article{doi107717peerj17060,
    author = "Perillo, Marcello and Sander, P. Martin",
    title = "The dinosaurs that weren’t: osteohistology supports giant ichthyosaur affinity of enigmatic large bone segments from the European Rhaetian",
    year = "2024",
    journal = "PeerJ",
    abstract = "from Canada were sampled for comparison. The results of the sampling indicate a common osteohistology with the European specimens. A broad histological comparison is provided to reject alternative taxonomic affinities aside from ichthyosaurs of the very large bone segment. Most importantly, we highlight the occurrence of shared peculiar osteogenic processes in Late Triassic giant ichthyosaurs, reflecting special ossification strategies enabling fast growth and achievement of giant size and/or related to biomechanical properties akin to ossified tendons.",
    url = "https://doi.org/10.7717/peerj.17060",
    doi = "10.7717/peerj.17060",
    openalex = "W4394612053",
    references = "garilli2009first"
}

Bone histology is a valuable tool for studying growth patterns and life history traits in animals. This study examines four Japanese sika deer (Cervus nippon) populations—mainland (Hokkaido and Chiba) and insular (Yakushima and Kerama Islands)—using femoral and tibial histology to investigate growth patterns and sexual dimorphism. Growth curves based on lines of arrested growth (LAGs) revealed slower growth rates in insular populations, supported by extensive parallel-fibered bone (PFB) development and reduced vascularity. Earlier external fundamental system (EFS) formation and epiphyseal fusion in mainland populations (three to four years) compared to insular populations (5.5 to 7.5 years) further support this finding. Sexual dimorphism was pronounced in mainland populations, with males exhibiting delayed EFS formation, epiphyseal fusion, and extensive bone remodeling than females. In contrast, the Kerama population showed no significant sex-related differences in remodeling, which may influence unique growth patterns. These findings highlight the influence of insularity, such as resource limitation and predator-free environments on life history traits, which could associate slower growth rates and delayed maturity in insular deer. This study underscores the utility of bone histology in understanding adaptive strategies of endemic and endangered mammals.

@article{doi103106ms20240050,
    author = "Hayashi, Shoji and Kubo, Mugino O.",
    title = "Bone Histology Suggests Insularity and Sex Differences in Japanese Sika Deer Growth (Cervus nippon)",
    year = "2025",
    journal = "Mammal Study",
    abstract = "Bone histology is a valuable tool for studying growth patterns and life history traits in animals. This study examines four Japanese sika deer (Cervus nippon) populations—mainland (Hokkaido and Chiba) and insular (Yakushima and Kerama Islands)—using femoral and tibial histology to investigate growth patterns and sexual dimorphism. Growth curves based on lines of arrested growth (LAGs) revealed slower growth rates in insular populations, supported by extensive parallel-fibered bone (PFB) development and reduced vascularity. Earlier external fundamental system (EFS) formation and epiphyseal fusion in mainland populations (three to four years) compared to insular populations (5.5 to 7.5 years) further support this finding. Sexual dimorphism was pronounced in mainland populations, with males exhibiting delayed EFS formation, epiphyseal fusion, and extensive bone remodeling than females. In contrast, the Kerama population showed no significant sex-related differences in remodeling, which may influence unique growth patterns. These findings highlight the influence of insularity, such as resource limitation and predator-free environments on life history traits, which could associate slower growth rates and delayed maturity in insular deer. This study underscores the utility of bone histology in understanding adaptive strategies of endemic and endangered mammals.",
    url = "https://doi.org/10.3106/ms2024-0050",
    doi = "10.3106/ms2024-0050",
    openalex = "W4409053671",
    references = "cubo2021bone, doi101007978148995740520, doi101016s1631069102014294, doi101017s0952836904004844, doi101073pnas0813385106, doi101098rsbl20230245, doi101111j13652699201102656x, doi101371journalpone0178691, doi103106ms20230079, erickson2014on, köhler2012seasonal"
}