Analysing Thalattosuchia palaeobiodiversity through the prism of phylogenetic comparative methods

• Published in: Palaeontology Vol. 68; no. 1
• Main Authors: Forêt, Tom, Aubier, Paul, Jouve, Stéphane, Cubo, Jorge
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.01.2025; Wiley
• Subjects: Abiotic factors; Animal biology; Biodiversity; Cretaceous; Diet; Earth Sciences; Ecological distribution; Jurassic; Life Sciences; Niche overlap; Niches; palaeobiodiversity; Paleontology; phylogenetic comparative methods; Phylogenetics; Phylogeny; Range extension; Sciences of the Universe; Statistical analysis; Statistical methods; Systematics, Phylogenetics and taxonomy; Thalattosuchia; Vertebrate Zoology; phylogenetic comparative methods; Thalattosuchia; palaeobiodiversity
• ISSN: 0031-0239; 1475-4983
• DOI: 10.1111/pala.70000

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