Anatomy and relationships of the early diverging Crocodylomorphs Junggarsuchus sloani and Dibothrosuchus elaphros

The Anatomical Record, Journal Year: 2022, Volume and Issue: 305(10), P. 2463 - 2556

Published: June 14, 2022

Abstract The holotype of Junggarsuchus sloani , from the Shishugou Formation (early Late Jurassic) Xinjiang, China, consists a nearly complete skull and anterior half an articulated skeleton, including pectoral girdles, forelimbs, vertebral column, ribs. Here, we describe its anatomy compare it to other early diverging crocodylomorphs, based in part on CT scans that Dibothrosuchus elaphros Early Jurassic China. shares many features with cursorial assemblage informally known as “sphenosuchians,” whose relationships are poorly understood. However, also displays several derived crocodyliform not found among most “sphenosuchians.” Our phylogenetic analysis corroborates hypothesis is closer Crocodyliformes, living crocodylians, than Sphenosuchus but close crocodyliforms Almadasuchus Macelognathus “Sphenosuchia” paraphyletic assemblage. D. acutus hypothesized be more closely related Crocodyliformes remaining non‐crocodyliform which form smaller groups largely unresolved.

Language: Английский

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A new early diverging thalattosuchian (Crocodylomorpha) from the Early Jurassic (Pliensbachian) of Dorset, U.K. and implications for the origin and evolution of the group

Journal of Vertebrate Paleontology, Journal Year: 2022, Volume and Issue: 42(3)

Published: Sept. 30, 2022

Among archosaurs, thalattosuchian crocodylomorphs experienced the most extensive adaptations to marine realm. Despite significant attention, phylogenetic position of group remains uncertain. Thalattosuchians are either sister-group Crocodyliformes, basal mesoeucrocodylians, or nest among longirostrine neosuchians. The earliest definite thalattosuchians Toarcian, and already possess many synapomorphies group. All hypotheses imply a ghost lineage extending at least Sinemurian, lack older more plesiomorphic forms may contribute uncertain placement Here we describe new species, Turnersuchus hingleyae, gen. et sp. nov., from early Pliensbachian Belemnite Marl Member Charmouth Mudstone Formation (Dorset, U.K.). specimen includes partially articulated cranial, mandibular, axial, appendicular elements. It can be attributed Thalattosuchia based on following features: distinct fossa posterolateral corner squamosal; broad ventrolateral process otoccipital covering dorsal surface quadrate; large supratemporal fenestrae lacking flattened skull table; broadly exposed prootic; orbital quadrate bony attachment with braincase. This represents currently known diagnostic material. Phylogenetic analyses two published datasets recover as diverging thalattosuchian, sister Teleosauroidea + Metriorhynchoidea. Bayesian tip-dating suggest Rhaetian Sinemurian divergence other crocodylomorphs, depending topology, confidence intervals spanning Norian Pliensbachian. extends fossil record Thalattosuchia, but time-scaling demonstrate that remains.

Language: Английский

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The postcranial anatomy and osteohistology of Terrestrisuchus gracilis (Archosauria, Crocodylomorpha) from the Late Triassic of Wales

Papers in Palaeontology, Journal Year: 2024, Volume and Issue: 10(4)

Published: July 1, 2024

Abstract The earliest crocodylomorphs, known as non‐crocodyliform first appeared during the Late Triassic. In contrast to extant crocodylians, which are all semi‐aquatic, early crocodylomorphs represent terrestrial taxa with a fully erect posture and in most cases small body size. Their gracile skeletons suggest an active mode of life, possibly similar contemporaneous, bipedal theropod dinosaurs. Despite this remarkable plan, postcranial morphology has rarely been documented detail, restricting our ability infer aspects their functional evolution. Here, we provide detailed description postcranium Terrestrisuchus gracilis , small‐bodied crocodylomorph from Triassic Pant‐y‐Ffynnon Quarry (southern Wales, UK), including long bone tissues based on histological thin sections. Almost elements skeleton have preserved. is highly gracile, even for crocodylomorph. Osteological correlates appendicular that had digitigrade, quadrupedal posture. A quantitative analysis limb robustness corroborates was quadruped. Histological suggests sampled specimens were skeletally immature fast growth at time death, indicated by lack external fundamental system predominance fibrolamellar bone. tissue recently described Saltoposuchus connectens certain non‐crocodylomorph pseudosuchians, but differs Hesperosuchus agilis crocodyliforms, parallel‐fibred more prevalent.

Language: Английский

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A review of the non‐semiaquatic adaptations of extinct crocodylomorphs throughout their fossil record

The Anatomical Record, Journal Year: 2024, Volume and Issue: 308(2), P. 266 - 314

Published: Nov. 25, 2024

Abstract Crocodylomorphs constitute a clade of archosaurs that have thrived since the Mesozoic until today and survived numerous major biological crises. Contrary to historic belief, their semiaquatic extant representatives (crocodylians) are not living fossils, and, during evolutionary history, crocodylomorphs evolved live in variety environments. This review aims summarize non‐semiaquatic adaptations (i.e., either terrestrial or fully aquatic) different groups from periods, highlighting how exactly those lifestyles inferred for animals, with regard geographic temporal distribution phylogenetic relationships. The ancestral condition Crocodylomorpha seems been lifestyle, linked several morphological such as an altirostral skull, long limbs allowing erect posture specialized dentition diets based on land. However, some members this clade, thalattosuchians dyrosaurids display opposite, aquatic interestingly same type observations. Finally, new techniques inferring paleobiology extinct animals put forward last decade, appearing complementary approach traditional descriptions comparisons. Such is case paleoneuroanatomical (CT scan data), histological, geochemical studies.

Language: Английский

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Analysing Thalattosuchia palaeobiodiversity through the prism of phylogenetic comparative methods

Palaeontology, Journal Year: 2025, Volume and Issue: 68(1)

Published: Jan. 1, 2025

Abstract Thalattosuchia are a particularly diverse group of mostly marine crocodylomorphs that lived during most the Jurassic and Lower Cretaceous. Previous studies have sought to uncover factors influencing Crocodylomorpha evolution, yielding mixed results, possibly due Thalattosuchia's unique ecological niche controversial phylogenetic placement among crocodylomorphs. Here, we propose Thalattosuchia‐focused study using phylogenetically‐informed statistical analyses. First, tested structure thalattosuchian extinction at various geological transitions. We then influence biotic abiotic explaining diversity aforementioned crises. Finally, whether diet was an additional explanatory factor. found that: (1) Lower–Middle transition phylogenetically structured associated with signs snout reduction explained by colonization emptied niches, allowing emergence Machimosaurinae Geosaurinae; (2) observed higher local temperatures for after Middle–Upper Jurassic–Cretaceous transitions, former being in accordance climatic literature latter subject more caution; finally, (3) corroborated previous about skull shape durophagous teleosauroids tended larger body sizes than any other diet, as result specialization. also evidence partitioning piscivorous macrophagous metriorhynchoids is observable size range extension.

Language: Английский

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A new crocodylomorph (Pseudosuchia, Crocodylomorpha) from the Upper Triassic of Texas and its phylogenetic relationships

Journal of Vertebrate Paleontology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 11, 2025

Language: Английский

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The neuroanatomy and pneumaticity of Hamadasuchus (Crocodylomorpha, Peirosauridae) from the Cretaceous of Morocco and its paleoecological significance for altirostral forms

Journal of Anatomy, Journal Year: 2023, Volume and Issue: 243(3), P. 374 - 393

Published: June 13, 2023

We describe the endocranial structures of Hamadasuchus, a peirosaurid crocodylomorph from late Albian-Cenomanian Kem group Morocco. The cranial endocast, associated nerves and arteries, endosseous labyrinths, pneumatization, as well bones braincase new specimen, are reconstructed compared with extant fossil crocodylomorphs, which represent different lifestyles. Cranial this specimen identified belonging to close affinities Rukwasuchus yajabalijekundu, another 'middle' Cretaceous Tanzania. comparable those R. yajabalijekundu but also baurusuchids sebecids (sebecosuchians). Paleobiological traits such alert head posture, ecology, behavior explored for first time, using quantitative metrics. expanded narrow semi-circular canals enlarged pneumatization skull Hamadasuchus linked terrestrial lifestyle. Continuing work on neuroanatomy supposedly crocodylomorphs needs be broadened other groups will allow characterize whether some internal affected by lifestyle these organisms.

Language: Английский

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A revision and histological investigation of Saltoposuchus connectens (Archosauria: Crocodylomorpha) from the Norian (Late Triassic) of south-western Germany

Zoological Journal of the Linnean Society, Journal Year: 2023, Volume and Issue: 199(2), P. 354 - 391

Published: June 20, 2023

Abstract Crocodylomorpha is the stem-lineage of modern crocodylians and only pseudosuchian (i.e. crocodylian-line archosaurs) clade that survived Triassic–Jurassic mass extinction event. Its earliest members, non-crocodyliform crocodylomorphs, also known as ‘sphenosuchians’, were terrestrial mostly small-bodied (<2 m long), although some large-bodied forms are known. Saltoposuchus connectens one first described crocodylomorph species but it remains poorly studied, in part due to its contentious taxonomy. Here, all referred specimens detail for time taxonomy revised, with additional taxonomic implications British Terrestrisuchus gracilis coelophysoid theropod Procompsognathus triassicus. clearly distinguished from based on both cranial postcranial features. The phylogenetic analysis finds connectens, gracilis, Litargosuchus leptorhynchus form a gracile, long-legged identified Saltoposuchidae Crush 1984. A histological section femur reveals highly vascularized fibrolamellar tissue second-largest specimen (SMNS 12596), indicating sustained high growth rates. similar pattern was previously observed sp., contrasting slower rates Hesperosuchus agilis. These findings suggest saltoposuchids had resting metabolic rate active lifestyle.

Language: Английский

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Paleoherpetology and The Anatomical Record

The Anatomical Record, Journal Year: 2025, Volume and Issue: unknown

Published: March 17, 2025

The field of paleontology has long been dominated by charismatic species, such as ever-imposing dinosaurs and intriguingly anthropomorphic primates. However, alongside each dinosaur primate lived a variety other fossil often smaller reptiles, which typically receive dramatically less public scientific attention. Nevertheless, paleoherpetology, the study reptiles (typically used to refer non-dinosaurian fauna), provides an important framework for understanding broader context past ecosystems. Over several years, paleoherpetological studies have subject considerable number articles in Anatomical Record (AR). In this special issue Record, we celebrate paleoherpetology. Specifically, volume brings together collection papers on topics ranging from crocodyliforms turtles lizards. skillfully Guest Edited two experts Drs. Adán Pérez-García Francisco Ortega (Figure 1). is researcher at Evolutionary Biology Group National University Distance Education (UNED, Madrid, Spain), Senior Lecturer ("Profesor Titular de Universidad") Faculty Sciences that University. His main research evolutionary history turtles, both European forms taxa related them inhabited continents, especially Africa. He currently active Cenozoic while he also continues work with Mesozoic taxa, sites reptiles. participated projects involve analysis reptile faunas, Mesozoic, primary more than 10 projects, involving researchers various countries continents. director paleontological excavation campaigns, author 150 300 conference presentations. described 35 new genera species most but crocodiles sauropterygians. Professor UNED (Madrid) Principal Investigator Research UNED, focusing particularly dinosaurs, along their authored over 100 publications technical journals, primarily concentrating Upper Jurassic Portugal, well Lower Cretaceous Paleogene Spain. Furthermore, contributed development museum museographic efforts extend Spain, Niger, Argentina, participation nearly excavations twenty national international projects. We wish express our sincere thanks excellent issue. first true appeared record around 320 million years ago since undergone dramatic diversification evolution. Unique anatomical adaptations allowed paleoherp fauna survive Cretaceous-Paleogene (K-Pg) extinction event wiped out non-avian dinosaurs. AR many findings. This introductory editorial will briefly report some significant prior volumes AR. 2022, published its second largest ever, "The Age Crocodilians kin: Their anatomy, physiology evolution" (Holliday & Schachner, 2022; Laitman Smith, 2022). Special Issue began early Triassic crocodylomorphs (Bestwick et al., 2021; Melstrom Parker Ruebenstahl von Baczko 2021) extended through radiation during rest (Bowman Cowgill Dumont Jr. 2020; Fernandez Herrera, Nieto Wilberg 2021). Finally, it concluded presenting into crocs (Brochu Pochat-Cottilloux 2023, resulting 2022 Turtle Evolution Symposium (TES) (Smith Laitman, 2023; Sterli Vlachos, 2023). TES regular studying different aspects origin evolution until recent times. Topics relating ranged osteohistology (Guerrero Pérez-García, Pereyra, 2023) neuroanatomy (Martín-Jiménez Smith descriptions (Brinkman Gentry Joyce Maniel Vlachos documenting turtle occurrences (Boneta Jiménez Saltsidou A paleohistology pseudosuchians yielded exciting papers. models estimate body mass (Woodward 2024) review across Pseudosuchia (Scheyer, 2024). addition Issues, recently numerous standalone Studies focused amphisbaenian squamates (Salvino 2024), materials lizards (Loreal New crocodyliform (Noto 2019), ontogeny baurusuchids (dos Martins Santos Papers variation extant morphology relation (Evers Hermanson 2024; Miller discussed among (Adrian Tooth replacement mesosaurs (Carlisbino Modern studied way interpret (e.g., Allemand, Abdul-Sater, López-Aguirre, Maliuk all, provide paleoenvironmental information. They fill missing gaps ecosystems between widely mammals. hope you enjoy paleoherpetology Issue. Heather F. Smith: Writing – original draft; investigation; visualization; conceptualization. Jeffrey T. Laitman: writing editing.

Language: Английский

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Neuroanatomy of the crocodylian Tomistoma dowsoni from the Miocene of North Africa provides insights into the evolutionary history of gavialoids

Journal of Anatomy, Journal Year: 2023, Volume and Issue: 243(1), P. 1 - 22

Published: March 16, 2023

Abstract The interrelationships of the extant crocodylians Gavialis gangeticus and Tomistoma schlegelii have been historically disputed. Whereas molecular analyses indicate a sister taxon relationship between these two gavialoid species, morphological datasets typically place as outgroup to all other crocodylians. Recent morphological‐based phylogenetic begun resolve this discrepancy, recovering closest living relative ; however, several stratigraphically early fossil taxa are recovered closer than , resulting in anomalously divergence timings. As such, additional data might be required remaining discrepancies. ‘ ’ dowsoni is an extinct species from Miocene North Africa. Utilising CT scans near‐complete, referred skull, we reconstruct neuroanatomy neurosensory apparatus . Based on qualitative quantitative morphometric comparisons with crocodyliforms, characterised by intermediate morphology gavialoids, more closely resembling This mirrors results recent studies based external anatomy three gavialoids. Several neuroanatomical features appear reflect ecological and/or signals. For example, ‘simple’ their broadly similar that long narrow‐snouted (longirostrine), aquatic crocodyliforms. A dorsoventrally short, anteroposteriorly endosseous labyrinth also associated longirostry. These snout skull morphology, which themselves partly constrained ecology, exert influence has recognised birds turtles. Conversely, presence pterygoid bulla its absence could interpreted signal related Gaviali s Evaluation gavialoids will needed further test whether primarily or signal. By incorporating such previously inaccessible information into macroecological studies, can potentially constrain clade's interrelationships, well evaluate timing association evolution features. Finally, our study supports being phylogenetically indicating necessity taxonomic revision species.

Language: Английский

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