The history, systematics, and nomenclature of Thalattosuchia (Archosauria: Crocodylomorpha)

Zoological Journal of the Linnean Society, Journal Year: 2024, Volume and Issue: 200(2), P. 547 - 617

Published: Jan. 9, 2024

Abstract The use of more than one nomenclatural code is becoming increasingly common in some biological sub-disciplines. To minimize instability, we have decided to establish a higher level systematization for Thalattosuchia under both the International Code Phylogenetic Nomenclature (‘PhyloCode’) and Zoological (‘Zoological Code’). We undertook series phylogenetic analyses with an expanded dataset examine origins within Crocodylomorpha, determined clade’s diagnostic characters. Based on these analyses, provide updated diagnoses its subclades PhyloCode Code. also introduce two new nomina that are regulated (Neothalattosuchia Euthalattosuchia), nomen Dakosaurina, which registered codes. Moreover, PhyloCode-compliant definitions subclades. As cannot reliably discriminate between positional hypotheses clades’ as much mystery today they were over century ago. However, hope using same characters define clades, nomina, codes will be example others follow.

Language: Английский

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New Cretaceous neosuchians (Crocodylomorpha) from Thailand bridge the evolutionary history of atoposaurids and paralligatorids

Zoological Journal of the Linnean Society, Journal Year: 2024, Volume and Issue: 202(2)

Published: Jan. 9, 2024

Abstract The origin of modern crocodylians is rooted in the Cretaceous, but their evolutionary history obscure because relationships outgroups and transitional forms are poorly resolved. Here, we describe a new form, Varanosuchus sakonnakhonensis gen. nov., sp. from Early Cretaceous Thailand that fills an gap between Paralligatoridae Atoposauridae, two derived neosuchian lineages with previously unsettled phylogenetic relationships. Three individuals, including complete skull associated postcranial remains, allow for detailed description analysis. taxon distinguished all other crocodylomorphs by association features, narrow altirostral morphology, dorsal part postorbital anterolaterally facing edge, depression on posterolateral surface maxilla, fully pterygoid-bound choanae. A analysis confirms monophyly taxonomic content Atoposauridae Paralligatoridae, underline difficulty reaching robust definition Eusuchia. Furthermore, put forward further arguments related to putative terrestrial ecology semi-aquatic affinities atoposaurids based snout morphology osteoderm ornamentation.

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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Cladistic estimates of evolutionary rates focused on palaeontological datasets using TNT

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

Published: Jan. 30, 2025

Abstract We describe a protocol for estimating evolutionary rates from phylogenetic trees based on parsimony character optimization. The rate estimation is conducted through TNT script and the results are analysed in software environment R. allows analysing multiple optimal topologies, considering optimization ambiguity, alternative time‐calibrations or pre‐calibrated trees. R summarizes estimated consensus tree plots variation of time, jointly with diversity new metric (clade completeness index) that measures distribution missing data along tree. present simulated empirical analyses, evaluate impact calibration methods estimates. found while can lower nominal values rates, overall pattern time remained robust. Empirical cases highlight different scenarios, such as datasets which peaks be coupled decoupled diversification dynamics (phylogenetic diversity) may influence rates. conclude recommendations using this interpreting parsimony‐based

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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Thalattosuchian crocodylomorphs from the Sinemurian (Early Jurassic) of the UK

Zoological Journal of the Linnean Society, Journal Year: 2024, Volume and Issue: 201(3)

Published: July 1, 2024

Abstract Thalattosuchian crocodylomorphs were a ubiquitous component of shallow marine ecosystems during the Jurassic and Early Cretaceous. Alas, their origins remain mystery. Here we describe three specimens from Sinemurian (and possibly Pliensbachian) UK: partial cranial rostrum, series cervical vertebrae, two dorsal vertebrae adhered with matrix. These are amongst oldest known thalattosuchian fossils, rostrum being non-neothalattosuchian thalattosuchian. This has unique combination rostral characters never seen before in any crocodylomorph, helps to elucidate early internal evolution, suggesting that reduction paranasal sinuses was not related either reorganization neurovasculature later diverging taxa or increased cancellous bone microstructure. Based on our CT sample, shift microstructure occurred Eoneustes + Metriorhynchidae subclade, one coincided enlargement salt glands decoupling external antorbital fenestra sinuses. Without extensive histological sampling cannot determine whether an obligate aquatic lifestyle prior evolution Metriorhynchidae.

Language: Английский

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Functional and phylogenetic signals in the pectoral girdle of Thalattosuchia and Dyrosauridae (Crocodylomorpha)

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

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Description and phylogenetic relationships of a new species of Torvoneustes (Crocodylomorpha, Thalattosuchia) from the Kimmeridgian of Switzerland

PeerJ, Journal Year: 2023, Volume and Issue: 11, P. e15512 - e15512

Published: July 19, 2023

Metriorhynchids are marine crocodylomorphs found across Jurassic and Lower Cretaceous deposits of Europe Central South America. Despite being one the oldest fossil families named in paleontology, phylogenetic relationships within Metriorhynchidae have been subject to many revisions over past 15 years. Herein, we describe a new metriorhynchid from Kimmeridgian Porrentruy, Switzerland. The material consists relatively complete, disarticulated skeleton preserving pieces skull, including frontal, prefrontals, right postorbital, nasals, maxillae, premaxillae nearly entire mandible, remains axial appendicular such as cervical, dorsal, caudal vertebrae, ribs, left ischium, femur, fibula. This specimen is referred species Torvoneustes jurensis sp. nov. part large-bodied macrophagous tribe Geosaurini. presents unique combination cranial dental characters smooth cranium, frontal shape, acute ziphodont teeth, an enamel ornamentation made numerous apicobasal ridges shifting small forming anastomosed pattern toward apex crown touching carina. description this allows take look at currently proposed evolutionary trends genus provides information on evolution clade.

Language: Английский

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Reappraisal of the thalattosuchian crocodylomorph record from the Middle-Upper Jurassic Rosso Ammonitico Veronese of northeastern Italy: Age calibration, new specimens and taphonomic biases

PLoS ONE, Journal Year: 2023, Volume and Issue: 18(10), P. e0293614 - e0293614

Published: Oct. 30, 2023

Despite their extremely rare and fragmentary record, aquatic crocodylomorphs from the Middle to Upper Jurassic (Bajocian-Tithonian) Rosso Ammonitico Veronese (RAV) of northeastern Italy have sparked interest since late 18th century. Among marine reptiles, Thalattosuchia is by far one best represented groups RAV units, especially in Jurassic. Although some specimens been subject multiple studies recent times, most them still lack precise stratigraphic assignment taphonomic assessment, while others remain undescribed. Here we provide a comprehensive revision thalattosuchian record RAV, alongside up-to-date age determination, means calcareous nannofossils, when available. Three new metriorhynchoid are described for first time Asiago Plateau (Vicenza province). While taphonomy newly hampers any taxonomic attribution below superfamily/family level, all three were confidently assigned interval between upper Bajocian Bathonian. This revised has major paleobiogeographical implications: confirm an early origin distribution Metriorhynchoidea Tethys area suggest fast colonization open-ocean environment Bajocian.

Language: Английский

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A phytosaur osteoderm from a late middle Rhaetian bone bed of Bonenburg (North Rhine-Westphalia, Germany): Implications for phytosaur extinction

Fossil record, Journal Year: 2024, Volume and Issue: 27(1), P. 147 - 158

Published: March 13, 2024

Although there are problematic earliest Jurassic records, phytosaurs thought to have become extinct during the Rhaetian. A newly-discovered left paramedian phytosaur osteoderm from a clay pit in Bonenburg, Kreis Höxter, North Rhine-Westphalia, Germany, is youngest, well-dated record. This was found bone bed (Bone Bed 2) Contorta Beds of Rhaetian Exter Formation. Palynology constrains age Bone 2 late middle (ca. 203.5 million years ago). The Bonenburg cannot be assigned any named species. It most closely resembles some osteoderms Halberstadt Central Germany. Phytosaurs survived Europe at least Rhaetian, probably falling victim end-Triassic extinction event about two later.

Language: Английский

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