The internal braincase anatomy of Thalattosuchus superciliosus – with implications for the endocranial evolution of metriorhynchid crocodylomorphs DOI Creative Commons
Robert Higgins, Thomas Cowgill, Mark T. Young

et al.

Historical Biology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 12

Published: Nov. 29, 2024

Thalattosuchian crocodylomorphs underwent a major evolutionary transition, evolving from semiaquatic forms reminiscent of extant crocodylians, into pelagic marine with flippers, tail fin and smooth scaleless skin. These fully aquatic – the Metriorhynchidae evolved novel suite endocranial anatomies hypothesised to be related living in saltwater. However, much remains discovered about evolution these internal braincase structures. Herein, we describe anatomy an early diverging metriorhynchid, Thalattosuchus superciliosus, using microfocus computed tomography (μCT) data three-dimensional modelling. We compared it against geosaurine metriorhynchine metriorhynchids, as well metriorhynchoid Pelagosaurus. found that non-geosaurine metriorhynchids differ geosaurines having less laterally expanded cerebral hemispheres, shallower curvatures brain's dorsal margin, lacking ventral deflection pneumatic diverticulum pituitary fossa chamber. early-diverging have well-defined otoccipital diverticula lacked 'extreme pelagic' endosseous labyrinth morphology. hypothesise were not adapted sustained pursuit lifestyle. Moreover, posit within both metriorhynchid subfamilies there was parallel towards becoming predators.

Language: Английский

Pseudosuchian thermometabolism: A review of the past two decades DOI Creative Commons
Mathieu G. Faure‐Brac

The Anatomical Record, Journal Year: 2024, Volume and Issue: 308(2), P. 315 - 341

Published: Dec. 16, 2024

Abstract Pseudosuchia, one of the two main clades Archosauria, is today only represented by some 20 extant species, crocodilians, representing a fraction its extinct diversity. Extant crocodilians are ectotherms but present morphological and anatomical features usually associated with endothermy. In 2004, it was proposed that pseudosuchians were ancestrally endothermic observed in remains this lost legacy. This contribution has parts: first part covers years studies on subject, exploring evidence for loss endothermy before covering variety proxies used to infer thermophymetabolic regime pseudosuchians. second part, quantitative results these previous integrated into comprehensive ancestral state reconstruction discuss potential scenario evolution thermometabolism. Pseudosuchian would then have been close node Crocodylomorpha. The end‐Triassic mass extinction played role filter, leading survival ectothermic ones. difference Pseudosuchia compared those dinosaurs, their metabolism also considered. might different level than dinosaurian more expected clarify question.

Language: Английский

Citations

4

A re-description of the teleosauroid Macrospondylus bollensis (Jaeger, 1828) from the Posidonienschiefer Formation of Germany DOI Creative Commons
Michela M. Johnson, Sven Sachs, Mark T. Young

et al.

PalZ, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

Language: Английский

Citations

0

Functional and phylogenetic signals in the pectoral girdle of Thalattosuchia and Dyrosauridae (Crocodylomorpha) DOI Open Access
Isaure Scavezzoni, Michela M. Johnson, Stéphane Jouve

et al.

The Anatomical Record, Journal Year: 2024, Volume and Issue: 308(2), P. 412 - 573

Published: Nov. 25, 2024

Abstract Crocodylomorphs have colonized various environments from fully terrestrial to aquatic, making it an important clade among archosaurs. A remarkable example of the rich past diversity Crocodylomorpha Hay, 1930 is marine colonization undergone by several crocodylomorph lineages, particularly Thalattosuchia Fraas, 1901 during Early Jurassic–Early Cretaceous, and Dyrosauridae de Stefano, 1903 Late Cretaceous–Early Eocene. represents most impressive singular radiation Crocodylomorpha, occupying ecological niches, before enigmatically disappearing in Cretaceous. Dyrosauridae, on other hand, known for surviving end‐Cretaceous mass extinction abundance but subsequently vanished. The evolutionary path undertaken crocodylomorphs into aquatic reasons their disappearance outside events Mesozoic remains a mystery. Despite well‐preserved fossil record, attention has primarily centered craniodental adaptations, overlooking swimming‐related adaptations recorded postcranial skeleton. This research involves comprehensive examination pectoral girdle representative members highlighting trajectories over time. Additionally, this work aims test phylogenetic signal residing anatomy Crocodylomorpha. As such, recent complete dataset been repurposed: 42 new characters added others revised address our question. We stress that constitutes tool supply better understand relations extinct crocodyliforms, also offers insights development, ecology, biomechanics.

Language: Английский

Citations

2

The internal braincase anatomy of Thalattosuchus superciliosus – with implications for the endocranial evolution of metriorhynchid crocodylomorphs DOI Creative Commons
Robert Higgins, Thomas Cowgill, Mark T. Young

et al.

Historical Biology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 12

Published: Nov. 29, 2024

Thalattosuchian crocodylomorphs underwent a major evolutionary transition, evolving from semiaquatic forms reminiscent of extant crocodylians, into pelagic marine with flippers, tail fin and smooth scaleless skin. These fully aquatic – the Metriorhynchidae evolved novel suite endocranial anatomies hypothesised to be related living in saltwater. However, much remains discovered about evolution these internal braincase structures. Herein, we describe anatomy an early diverging metriorhynchid, Thalattosuchus superciliosus, using microfocus computed tomography (μCT) data three-dimensional modelling. We compared it against geosaurine metriorhynchine metriorhynchids, as well metriorhynchoid Pelagosaurus. found that non-geosaurine metriorhynchids differ geosaurines having less laterally expanded cerebral hemispheres, shallower curvatures brain's dorsal margin, lacking ventral deflection pneumatic diverticulum pituitary fossa chamber. early-diverging have well-defined otoccipital diverticula lacked 'extreme pelagic' endosseous labyrinth morphology. hypothesise were not adapted sustained pursuit lifestyle. Moreover, posit within both metriorhynchid subfamilies there was parallel towards becoming predators.

Language: Английский

Citations

1