Henry S. Sharpe, Mark J. Powers, Michael W. Caldwell
{"title":"Reassessment of Xenodens calminechari with a discussion of tooth morphology in mosasaurs","authors":"Henry S. Sharpe, Mark J. Powers, Michael W. Caldwell","doi":"10.1002/ar.25612","DOIUrl":"10.1002/ar.25612","url":null,"abstract":"<p><i>Xenodens calminechari</i> is a mosasaurid taxon named by Longrich et al. (2021) based on the holotype MHNM.KH.331, a left maxilla with several teeth. This holotype was obtained nonscientifically (without technical supervision) from an area in Morocco that yields many manipulated or forged specimens. Examination of Longrich et al. (2021) reveals four tooth crowns occupy what appear to be two alveoli in MHNM.KH.331, and there is potential adhesive connecting the tooth crowns to the maxilla on their lateral sides. We argue that the articulated tooth crowns of this taxon were artificially placed in the maxilla, rendering at least two apomorphies of this taxon the product of forgery. Longrich et al. (2021)'s claims of fused tooth ‘roots' in MNHM.KH.331 are instead calcified periodontal ligament and alveolar bone that have ankylosed, resembling the typical mosasaurid condition. Differing tooth crown morphology does not preclude the referral of the teeth of this specimen to a younger ontogenetic stage of another mosasaur (possibly <i>Carinodens</i>) because many extant lizard species show drastic ontogenetic changes in the dentition. We argue that <i>Xenodens calminechari</i> represents a <i>nomen dubium</i>. This specimen constitutes a confluence of two persistent problems in vertebrate paleontology: material sourced from commercial excavations that has not been adequately tested for forgery, and taxa named from tooth-based holotypes that ignore the potential for intraspecific dental variation and interspecific convergence in dental characters, as are common in squamates. We suggest that Longrich et al. CT scan MHNM.KH.331, and we supply CT examples for identifying artificially added tooth crowns to Moroccan mosasaur jaws. Finally, we provide recommendations for the designation of mosasaurid holotypes.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 8","pages":"2160-2172"},"PeriodicalIF":2.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ar.25612","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142840195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mariana Valeria de Araujo Sena, Holly Noelle Woodward, Jorge Cubo
{"title":"Pseudosuchia: Masters of survival and diversification","authors":"Mariana Valeria de Araujo Sena, Holly Noelle Woodward, Jorge Cubo","doi":"10.1002/ar.25611","DOIUrl":"10.1002/ar.25611","url":null,"abstract":"<p>In the context of an increasing interest for Pseudosuchia, we have compiled a Special Issue, comprising 14 collaborative studies that deepen our understanding of pseudosuchian evolution. These contributions range from the description of a new taxon to exhaustive reviews of thermometabolism, morphological adaptation, systematics, and detailed investigations into ontogeny, paleoneurology, paleohistology, and paleobiology. Through these papers, we explore the evolutionary history of pseudosuchian archosaurs, spotlighting their rise and diversification following the end-Permian mass extinction.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 2","pages":"238-244"},"PeriodicalIF":2.1,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142824633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The velar chord and dynamic integration of the gular valve in crocodylians","authors":"Bruce A. Young, Michael Cramberg, Olivia G. Young","doi":"10.1002/ar.25608","DOIUrl":"10.1002/ar.25608","url":null,"abstract":"<p>Crocodylians evolved a unique gular valve that is capable of creating a water-tight seal between the oral and pharyngeal cavities, allowing the animal to safely submerge with an open mouth. The gular valve has traditionally been described as consisting of two separate parts: an active mobile ventral portion (consisting of the tongue and portions of the hyolingual apparatus) and a dorsal portion, which is a static fold on the hard palate (often termed the palatal velum). The results of the present study argue that the two portions of the gular valve are functionally integrated, not separate, and that the dorsal portion (herein the dorsal gular fold) is a dynamic element the shape and tension of which are influenced by active and passive forces. Using gross dissection, histology, and DiceCT, the present study documents a previously underscribed component of the gular valve, the velar chord, which links the hyolingual apparatus to the dorsal gular fold, functionally integrating the two halves of the gular valve. Through endoscopic videography and a variety of manipulations on living crocodylians, this study demonstrates that changes in the tension on the velar chord directly alter the shape and tension of the dorsal gular fold. The shape changes observed in the dorsal gular fold could be accommodated by a shallow depression in the ventral surface of the palatine bones, herein termed the velar fossa. The velar fossa is a prominent feature of <i>Alligator mississippiensis</i> and was observed in other crocodilians; however, a survey of living and fossil crocodylians demonstrated that the velar fossa is not a universal feature in this clade. Understanding the functional linkage between the dorsal and ventral portions of the gular valve has implications beyond the dive reflex of crocodylians, since active manipulation of the dorsal gular fold likely plays a role in a variety of behavioral and physiological processes such as deglutition and vocalization.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 8","pages":"2234-2249"},"PeriodicalIF":2.1,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ar.25608","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142781636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
João G. Franca, Marco Aurelio M. Freire, Antonio Pereira, Paul R. Manger, Jon H. Kaas, Cristovam W. Picanço-Diniz
{"title":"Cortico-cortical connectivity of the somatosensory cortex of the agouti: Topographical organization and evolutionary implications","authors":"João G. Franca, Marco Aurelio M. Freire, Antonio Pereira, Paul R. Manger, Jon H. Kaas, Cristovam W. Picanço-Diniz","doi":"10.1002/ar.25610","DOIUrl":"10.1002/ar.25610","url":null,"abstract":"<p>Understanding patterns of cortico-cortical connections in both frequently and infrequently studied species advances our knowledge of cortical organization and evolution. The agouti (<i>Dasyprocta aguti</i>, a medium-size South American rodent) offers a unique opportunity, because of its large lissencephalic brain and its natural behaviors, such as gnawing and hiding seeds, that require bimanual interaction while sitting on its hindlimbs and aligning its head to receive images of the horizon on the retinal visual streak. There have been no previous studies of the intrinsic and extrinsic ipsilateral projections of the agouti's primary somatosensory cortical area (S1). In the present study, we utilized biotinylated dextran (BDA) anatomical tract-tracer injections combined with microelectrode electrophysiological mapping, correlated with analysis of cytochrome oxidase (CO) histochemical staining, to investigate the ipsilateral corticocortical connectivity of the agouti's S1. By injecting BDA into electrophysiologically identified regions within the S1, we revealed ipsilateral intrinsic connections, as well as connections with cortical areas rostral and caudal to S1, and homotopic labeling in the second somatosensory cortical area (S2). In addition, we identified a focal cluster of labeled axons and axonal terminals adjacent to the rhinal fissure, tentatively named the parietal rhinal area (PR). The analysis of CO reactivity allowed delineation of the boundaries and subdivisions of S1, as well as the locations and limits of primary auditory and visual areas. These findings provide support for the notion of a similar pattern of somatosensory cortical organization and connectivity across mammalian species.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 9","pages":"2450-2468"},"PeriodicalIF":2.1,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142781633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thiago S. Fachini, Pedro L. Godoy, Felipe C. Montefeltro, Max C. Langer
{"title":"Cranial morphology and phylogenetic reassessment of Barreirosuchus franciscoi (Crocodylomorpha, Notosuchia), a Peirosauria from the Late Cretaceous of Brazil","authors":"Thiago S. Fachini, Pedro L. Godoy, Felipe C. Montefeltro, Max C. Langer","doi":"10.1002/ar.25607","DOIUrl":"10.1002/ar.25607","url":null,"abstract":"<p>With nearly 30 living species of relatively similar ecological traits, Crocodylomorpha is represented today by only a small fraction of its past diversity. The well-documented crocodylomorph fossil record has revealed more than 500 taxa, with much higher ecological and morphological diversity than their extant counterparts. An example of such astonishing diversity is the Late Cretaceous rocks of the Bauru Group (southeast Brazil), from which numerous taxa are known, belonging to the clade Notosuchia. These were predominantly terrestrial taxa, some of which exhibited traits associated with omnivorous or even herbivorous feeding behaviors, such as Sphagesauridae, whereas others were adapted to a carnivore diet, such as Baurusuchidae and Peirosauridae. Among these is <i>Barreirosuchus franciscoi</i>, originally described as a neosuchian (Trematochampsidae) but later interpreted as a peirosaurid notosuchian. Even though included in recent morphological and phylogenetic analyses, <i>B. franciscoi</i> still lacked a more detailed description. Here, we provide an in-depth description of the cranial elements of <i>B. franciscoi</i>, using data from computed tomography and a broad sample of comparative material, including living and fossil crocodylomorphs. Also, the neuro-cavities, including the endocast, nasopharyngeal duct, and the olfactory region, were digitally reconstructed. Finally, a new phylogenetic analysis recovered <i>B. franciscoi</i> nested within Peirosauria, forming the Itasuchidae clade with other potentially semiaquatic species: <i>Rukwasuchus yajabalajekundu</i>, <i>Pepesuchus deiseae</i>, and <i>Itasuchus jesuinoi</i>. The morphological and phylogenetic reassessment of <i>B. franciscoi</i> indicates a semiaquatic form, highlighting the ecological diversity of notosuchians from the Bauru Group as well as the capacity of notosuchians to explore a myriad of environments.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 2","pages":"736-769"},"PeriodicalIF":2.1,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142774613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Doris Haydee Rosero Salazar, Lucas Honnlee, Phuc Hoang Nguyen, Elliot Willis, Zi-Jun Liu
{"title":"Spatial relationships of oropharyngeal structures during respiration, chewing, and swallowing.","authors":"Doris Haydee Rosero Salazar, Lucas Honnlee, Phuc Hoang Nguyen, Elliot Willis, Zi-Jun Liu","doi":"10.1002/ar.25605","DOIUrl":"https://doi.org/10.1002/ar.25605","url":null,"abstract":"<p><p>Spatial relationships between oropharyngeal structures and their coordinated dynamics ensure proper adaptations in functions such as respiration, chewing, and swallowing. Thus, the aim of this study is to analyze spatial changes in the normal oropharynx during respiration and mastication. For this purpose, eight 7-8 months old Yucatan minipigs, four of each sex were used. X-ray fluoroscopy was recorded with the field of view focused on the oropharyngeal region. The x-ray video clips showing respiratory cycles and masticatory sequences were digitized and traced. Points to be digitized and traced were located on the soft palate, epiglottis, tongue base, and pharyngeal wall. An X-Y coordinate system was established to trace distances and directions of each structure (structural), and between structures (inter-structural) during phases of respiration, chewing stages, and swallowing episodes. During respiration, the soft palate showed the largest X-Y movements with the largest distance change (1.32 ± 0.64 mm). In contrast, distance changes in the tongue base were significantly smaller (0.32 ± 0.21 mm, p < 0.05). Notably, during chewing the tongue base and epiglottis showed major changes in distance and direction. Similarly, during swallowing the tongue base showed the largest changes (2.94 ± 1.28 mm) followed by the pharyngeal wall and epiglottis. Thus, although coordinated, each pharyngeal structure plays specific roles. Understanding of these spatial and specific dynamics in different oropharyngeal structures would provide the baseline to analyze the potential mechanisms of various swallowing and breathing disorders such as dysphagia and obstructive sleep apnea.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142774614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A review of the non-semiaquatic adaptations of extinct crocodylomorphs throughout their fossil record","authors":"Yohan Pochat-Cottilloux","doi":"10.1002/ar.25586","DOIUrl":"10.1002/ar.25586","url":null,"abstract":"<p>Crocodylomorphs constitute a clade of archosaurs that have thrived since the Mesozoic until today and have survived numerous major biological crises. Contrary to historic belief, their semiaquatic extant representatives (crocodylians) are not living fossils, and, during their evolutionary history, crocodylomorphs have evolved to live in a variety of environments. This review aims to summarize the non-semiaquatic adaptations (i.e., either terrestrial or fully aquatic) of different groups from different periods, highlighting how exactly those different lifestyles are inferred for those animals, with regard to their geographic and temporal distribution and phylogenetic relationships. The ancestral condition for Crocodylomorpha seems to have been a terrestrial lifestyle, linked with several morphological adaptations such as an altirostral skull, long limbs allowing a fully erect posture and a specialized dentition for diets based on land. However, some members of this clade, such as thalattosuchians and dyrosaurids display adaptations for an opposite, aquatic lifestyle, interestingly inferred from the same type of morphological observations. Finally, new techniques for inferring the paleobiology of those extinct animals have been put forward in the last decade, appearing as a complementary approach to traditional morphological descriptions and comparisons. Such is the case of paleoneuroanatomical (CT scan data), histological, and geochemical studies.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 2","pages":"266-314"},"PeriodicalIF":2.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142717658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Isaure Scavezzoni, Michela M. Johnson, Stéphane Jouve, Valentin Fischer
{"title":"Functional and phylogenetic signals in the pectoral girdle of Thalattosuchia and Dyrosauridae (Crocodylomorpha)","authors":"Isaure Scavezzoni, Michela M. Johnson, Stéphane Jouve, Valentin Fischer","doi":"10.1002/ar.25596","DOIUrl":"10.1002/ar.25596","url":null,"abstract":"<p>Crocodylomorphs have colonized various environments from fully terrestrial to fully aquatic, making it an important clade among archosaurs. A remarkable example of the rich past diversity of Crocodylomorpha Hay, 1930 is the marine colonization undergone by several crocodylomorph lineages, particularly Thalattosuchia Fraas, 1901 during the Early Jurassic–Early Cretaceous, and Dyrosauridae de Stefano, 1903 during the Late Cretaceous–Early Eocene. Thalattosuchia represents the most impressive and singular marine radiation among Crocodylomorpha, occupying various ecological niches, before enigmatically disappearing in the Cretaceous. Dyrosauridae, on the other hand, is known for surviving the end-Cretaceous mass extinction in abundance but subsequently vanished. The evolutionary path undertaken by crocodylomorphs into the aquatic environments and the reasons for their disappearance outside marine extinction events during the Mesozoic remains a mystery. Despite a well-preserved fossil record, attention has primarily centered on craniodental adaptations, overlooking the swimming-related adaptations recorded in the postcranial skeleton. This research primarily involves a comprehensive examination of the pectoral girdle of the most representative members of Thalattosuchia and Dyrosauridae, highlighting their evolutionary trajectories over time. Additionally, this work aims to test the phylogenetic signal residing in the postcranial anatomy of Crocodylomorpha. As such, the most recent and complete Crocodylomorpha phylogenetic dataset has been repurposed: 42 new postcranial characters have been added and several others have been revised to address our phylogenetic question. We stress that postcranial anatomy constitutes an important tool supply to better understand the relations of extinct crocodyliforms, but also offers insights on their development, ecology, and biomechanics.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 2","pages":"412-573"},"PeriodicalIF":2.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142717663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brodsky Dantas Macedo de Farias, Thiago Carlisbino, Bianca Martins Mastrantonio, Julia Brenda Desojo, Cesar Leandro Schultz, Marina Bento Soares
{"title":"The first ontogenetic model for non-crocodylomorph loricatans, based on osteohistology of the ontogenetic series of Prestosuchus chiniquensis from the Middle Triassic of Brazil","authors":"Brodsky Dantas Macedo de Farias, Thiago Carlisbino, Bianca Martins Mastrantonio, Julia Brenda Desojo, Cesar Leandro Schultz, Marina Bento Soares","doi":"10.1002/ar.25598","DOIUrl":"10.1002/ar.25598","url":null,"abstract":"<p><i>Prestosuchus chiniquensis</i> is an iconic non-crocodylomorph loricatan from the Brazilian Triassic beds and the best-known taxon, represented by several specimens. The completeness and preservation of its skeleton make it a valuable taxon for paleobiological studies. We explore the microstructure of bone tissues of appendicular elements and ribs of three specimens of <i>Prestosuchus</i> to access a variety of aspects of its paleobiology, such as histovariability, ontogeny, and growth patterns. Integrating our data and other osteohistologically studied <i>P. chiniquensis</i> specimens, we proposed for the first time an ontogenetic model for non-crocodylomorph loricatans. The model encompasses six distinct age classes (I–VI) that allow us to infer the growth patterns of <i>P. chiniquensis</i> and possibly expand to other phylogenetically close taxa. During early ontogeny (age classes I–II), sustained fast growth was maintained by a fibrolamellar complex. In mid ontogeny (age classes III–IV), highly vascularized parallel-fibered bone predominates, suggesting intermediary growth rates. A change for a poorly vascularized parallel-fibered/lamellar bone would mark the attainment of sexual (age classes IV–V) and skeletal maturity, comprising the age class VI. An external fundamental system (EFS) present in the outermost cortex is the main histological feature that characterize the age class VI. Major histovariability features are present between appendicular bones and ribs of skeletally immature individuals. The most prominent of them is the presence of fibrolamellar complex and highly vascularized parallel-fibered bone in appendicular bones and poorly vascularized parallel-fibered bone in ribs. In advanced ontogenetic stages, the histovariability between appendicular bones and ribs tends to be minor. Our data also support previous hypothesis of the presence of one new taxon among the specimens assigned to <i>P. chiniquensis</i>, increasing the diversity of non-crocodylomorph loricatans. The new taxon, represented by the specimen UFRGS-PV-0152-T, awaits a formal anatomical description. Our study advances the preliminary understand of the ontogeny and growth patterns of non-crocodylomorphs loricatans and Pseudosuchia as a whole.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 2","pages":"598-628"},"PeriodicalIF":2.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142677559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
William G. Parker, Michelle R. Stocker, William A. Reyes, Sarah Werning
{"title":"Anatomy and ontogeny of the “carnivorous aetosaur”: New information on Coahomasuchus kahleorum (Archosauria: Pseudosuchia) from the Upper Triassic Dockum Group of Texas","authors":"William G. Parker, Michelle R. Stocker, William A. Reyes, Sarah Werning","doi":"10.1002/ar.25600","DOIUrl":"10.1002/ar.25600","url":null,"abstract":"<p>A newly referred specimen of <i>Coahomasuchus kahleorum</i> (TMM 31100-437) from the lower part of the Upper Triassic Dockum Group of Texas preserves much of the skeleton including the majority of the skull. Introduced in the literature in the 1980s as the “carnivorous aetosaur”, TMM 31100-437 bears recurved teeth that previously were considered unique among aetosaurs. The small size of the individual led to speculation that it represents a skeletally immature individual that retains a plesiomorphic dentition for Archosauromorpha. We provide a detailed evaluation of the anatomy and phylogenetic relationships of this specimen. Apomorphies of the osteoderms and braincase support the referral of the specimen to <i>C. kahleorum</i>. Histological analysis of the femur demonstrates that TMM 31100-437 does not represent a juvenile form of another known aetosaur. Thus, TMM 31000-437 provides another case demonstrating that aetosaur species spanned a wide range of maximum body sizes, from approximately 1.5 m to over 5 m in length. Reanalysis of the type specimen of <i>C. kahleorum</i>, along with information from TMM 31000-437, demonstrates that the lateral osteoderms are not autapomorphic as previously described and have distinct lateral and medial flanges as well as a dorsal eminence. Overall, this specimen provides key details regarding body size and diet in an early occurring aetosaur.</p>","PeriodicalId":50965,"journal":{"name":"Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology","volume":"308 2","pages":"671-735"},"PeriodicalIF":2.1,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142649702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}