Osteohistological insight into the growth dynamics of early dinosaurs and their contemporaries

PLoS ONE, Journal Year: 2024, Volume and Issue: 19(4), P. e0298242 - e0298242

Published: April 3, 2024

Dinosauria debuted on Earth’s stage in the aftermath of Permo-Triassic Mass Extinction Event, and survived two other Triassic extinction intervals to eventually dominate terrestrial ecosystems. More than 231 million years ago, Upper Ischigualasto Formation west-central Argentina, dinosaurs were just getting warmed up. At this time, represented a minor fraction ecosystem diversity. Members tetrapod clades, including synapsids pseudosuchians, shared convergently evolved features related locomotion, feeding, respiration, metabolism could have risen later dominance. However, it was that radiated Mesozoic most significantly terms body size, diversity, global distribution. Elevated growth rates are one adaptations set apart, particularly from their contemporary crocodilian mammalian compatriots. When did elevated first evolve? How strategies earliest known compare with those tetrapods ecosystems? We studied femoral bone histology an array early alongside non-dinosaurian contemporaries order test whether oldest exhibited novel strategies. Our results indicate vertebrate fauna collectively exhibits relatively high rates. Dinosaurs among fastest growing taxa sample, but they occupied niche crocodylomorphs, archosauriformes, large-bodied pseudosuchians. Interestingly, these grew at least as quickly, more continuously sauropodomorph theropod Mesozoic. These data suggest that, while ancestral for likely played significant role dinosaurs’ ascent within ecosystems, not them apart contemporaries.

Language: Английский

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A new phylogenetic hypothesis of Tanystropheidae (Diapsida, Archosauromorpha) and other “protorosaurs”, and its implications for the early evolution of stem archosaurs

PeerJ, Journal Year: 2021, Volume and Issue: 9, P. e11143 - e11143

Published: May 3, 2021

The historical clade “Protorosauria” represents an important group of archosauromorph reptiles that had a wide geographic distribution between the Late Permian and Triassic. “Protorosaurs” are characterized by their long necks, which epitomized in genus Tanystropheus Dinocephalosaurus orientalis . Recent phylogenetic analyses have indicated is polyphyletic clade, but exact relationships various “protorosaur” taxa within lineage currently uncertain. Several taxa, although represented relatively complete material, previously not been assessed phylogenetically. We present new hypothesis comprises range archosauromorphs, including most exhaustive sample “protorosaurs” to date several from eastern Tethys margin included any previous analysis. polyphyly confirmed therefore we suggest usage this term should be abandoned. Tanystropheidae recovered as monophyletic Chinese Pectodens zhenyuensis form Dinocephalosauridae, closely related Tanystropheidae. well-known crocopod former Prolacerta broomi considerably less Archosauriformes than was considered.

Language: Английский

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Evaluating the ecology of Spinosaurus: shoreline generalist or aquatic pursuit specialist?

Palaeontologia Electronica, Journal Year: 2021, Volume and Issue: unknown

Published: Jan. 1, 2021

The giant theropod Spinosaurus was an unusual animal and highly derived in many ways, interpretations of its ecology remain controversial.Recent papers have added considerable knowledge the anatomy genus with discovery a new much more complete specimen, but this has also brought dramatic as specialised semi-aquatic that actively pursued aquatic prey.Here we assess arguments about functional morphology available data on possible habits light these finds.We conclude based data, degree adaptations for life are questionable, other tail fin features supported (e.g., socio-sexual signalling), pursuit predation hypothesis "highly specialized predator" is not supported.In contrast, 'wading' model predominantly fished from shorelines or within shallow waters contradicted by any line evidence well supported.Spinosaurus almost certainly fed primarily water may swum, there no it predator.

Language: Английский

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The marine conservation deposits of Monte San Giorgio (Switzerland, Italy): the prototype of Triassic black shale Lagerstätten

Swiss Journal of Palaeontology, Journal Year: 2024, Volume and Issue: 143(1)

Published: March 4, 2024

Abstract Marine conservation deposits (‘Konservat-Lagerstätten’) are characterized by their mode of fossil preservation, faunal composition and sedimentary facies. Here, we review these characteristics with respect to the famous deposit Besano Formation (formerly Grenzbitumenzone; including Anisian–Ladinian boundary), successively younger fossil-bearing units Cava inferiore, superiore, Cassina beds Kalkschieferzone Monte San Giorgio (Switzerland Italy). We compare a selection important black shale-type Lagerstätten global Phanerozoic plus Ediacaran in order detect commonalities facies, genesis, content using principal component hierarchical cluster analyses. Further, put type Fossillagerstätten into context other comparable Triassic worldwide based on content. The results analyses allow subdivision 45 analysed four groups, for which suggest use corresponding pioneering localities: Burgess early Palaeozoic shales, Holzmaden pyrite-rich shales Solnhofen platy limestones.

Language: Английский

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A redescription of Trachelosaurus fischeri from the Buntsandstein (Middle Triassic) of Bernburg, Germany: the first European Dinocephalosaurus-like marine reptile and its systematic implications for long-necked early archosauromorphs

Swiss Journal of Palaeontology, Journal Year: 2024, Volume and Issue: 143(1)

Published: March 15, 2024

Abstract Some of the earliest members archosaur-lineage (i.e., non-archosauriform archosauromorphs) are characterised by an extremely elongated neck. Recent fossil discoveries from Guanling Formation (Middle Triassic) southern China have revealed a dramatic increase in known ecomorphological diversity these long-necked archosauromorphs, including fully marine and viviparous Dinocephalosaurus orientalis . These recent merit reinvestigation enigmatic Triassic diapsid fossils contemporaneous European deposits housed historical collections. Here, we provide redescription Trachelosaurus fischeri , represented single, disarticulated specimen first described 1918. Due to its unique morphology, which includes short, bifurcating cervical ribs, high presacral vertebral count, this taxon has been referred either as “protorosaurian” archosauromorph or sauropterygian. Our revision clearly shows that represents unambiguous -like outside Formation. finding important systematic implications. Trachelosauridae Abel, 1919 senior synonym for recently identified Dinocephalosauridae Spiekman, Fraser Scheyer, 2021. Based on our phylogenetic analyses, employ two extensive datasets, also corroborate previous findings tanystropheids trachelosaurids represent families within larger monophyletic group among non-crocopodan is here named Tanysauria (clade nov.). minimally composed Pectodens zhenyuensis Austronaga minuta but one analyses found probably taxonomically broader clade may include Gracilicollum latens Fuyuansaurus acutirostris considerably expands spatial temporal range Anisian Central Basin. add growing evidence presence diverse reptiles during Middle Tanysauria. possess flipper-like limbs, counts, elongate necks, thus superficially resembling Jurassic Cretaceous plesiosaurs some regards.

Language: Английский

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Extreme neck elongation evolved despite strong developmental constraints in bizarre Triassic reptiles—implications for neck modularity in archosaurs

Royal Society Open Science, Journal Year: 2024, Volume and Issue: 11(5)

Published: May 1, 2024

The Triassic radiation of vertebrates saw the emergence modern vertebrate groups, as well numerous extinct animals exhibiting conspicuous, unique anatomical characteristics. Among these, members Tanystropheidae (Reptilia: Archosauromorpha) displayed cervical vertebral elongation to an extent unparalleled in any other vertebrate. Tanystropheids were exceptionally ecologically diverse and had a wide spatial temporal distribution. This may have been related their neck anatomy, yet its evolution functional properties remain poorly understood. We used geometric morphometrics capture intraspecific variation between vertebrae comprising column among early archosauromorphs, trace evolutionary history these animals. Our results show that series reptiles can be divided into modules corresponding those extant achieved through somite shift thoracic regions, without presacral count increase—contrary crown archosaurs. suggests peculiar developmental constraint strongly affected tanystropheids. data obtained just at base archosauromorph phylogenetic tree are crucial for further studies on modularity columns not only reptile groups but well.

Language: Английский

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A description of the palate and mandible of Youngina capensis (Sauropsida, Diapsida) based on synchrotron tomography, and the phylogenetic implications

Papers in Palaeontology, Journal Year: 2023, Volume and Issue: 9(5)

Published: Sept. 1, 2023

Abstract The late Permian reptile Youngina capensis ( c . 254 Ma) is a non‐saurian neodiapsid whose anatomy has been used to represent the reptilian condition prior divergence of Sauria (crown‐group reptiles). However, despite being first described over 100 years ago, remains incompletely documented. Here we use synchrotron x‐ray micro‐computed tomography document new features palate, braincase and mandible New observations include an anteriorly bifurcating vomer, dentition on ventral surface parasphenoid body cultriform process, strongly convex coronoid eminence. Our anatomical suggest that may more stemward lineage among neodiapsids this supported by our phylogenetic analysis, which places as early diverging neodiapsid. research will benefit future studies saurian origins providing improved constraints crown group.

Language: Английский

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The cranial morphology ofTanystropheus hydroides(Tanystropheidae, Archosauromorpha) as revealed by synchrotron microtomography

PeerJ, Journal Year: 2020, Volume and Issue: 8, P. e10299 - e10299

Published: Nov. 20, 2020

The postcranial morphology of the extremely long-necked Tanystropheus hydroides is well-known, but observations skull were previously limited due to compression known specimens. Here we provide a detailed description PIMUZ T 2790, including partial endocast and endosseous labyrinth, based on synchrotron microtomographic data, compare its that other early Archosauromorpha. In many features, such as wide flattened snout configuration temporal palatal regions, differs strongly from archosauromorphs. braincase possesses combination derived archosaur traits, presence laterosphenoid ossification lateral wall braincase, also archosauriforms in ventral ramus opisthotic, horizontal orientation parabasisphenoid, absence clearly defined crista prootica. was ram-feeder likely caught prey through laterally directed snapping bite. Although cranial archosauromorph lineages relatively well-represented, skulls most tanystropheid taxa remain poorly understood compressed often fragmentary recent descriptions Macrocnemus bassanii now reveal large disparity clade, reflecting ecological diversity, highlighting importance non-archosauriform Archosauromorpha both terrestrial aquatic ecosystems during Triassic.

Language: Английский

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Widespread azendohsaurids (Archosauromorpha, Allokotosauria) from the Late Triassic of western USA and India

Papers in Palaeontology, Journal Year: 2021, Volume and Issue: 8(1)

Published: Dec. 10, 2021

Abstract Archosauromorph reptiles underwent rapid lineage diversification, increases in morphological and body size disparity, expansion into new adaptive landscapes. Several of the primary early archosauromorph clades (e.g. rhynchosaurs) are easy to differentiate from others because their characteristic types, whereas more lizard‐like carnivorous forms with long necks tanystropheids) were historically all relegated groups Protorosauria or Prolacertiformes. However, it is now clear that these polyphyletic a lizard‐like, form plesiomorphic for Archosauromorpha, multiple subclades started plan. Among Malerisaurus Upper Triassic India ( M. robinsonae ) south‐western USA langstoni ). In this paper, we critically re‐evaluate genus. We find both species as valid, identify an diverging, but late‐surviving, member Azendohsauridae within Allokotosauria. Our histological analysis assessment ontogenetic changes limb bones small large individuals demonstrate skeletons grew slowly became robust through ontogeny, larger recovered at near maximum taxon. ‐like taxa common members Otischalkian–Adamanian (late Carnian mid‐Norian) faunal assemblages strata south western USA, they absent younger Revueltian holochronozone. Specimens North America show Allokotosauria had near‐Pangaean distribution much Middle Late Triassic.

Language: Английский

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The affinities of the Late Triassic Cryptovaranoides and the age of crown squamates

Royal Society Open Science, Journal Year: 2023, Volume and Issue: 10(10)

Published: Oct. 1, 2023

Most living reptile diversity is concentrated in Squamata (lizards, including snakes), which have poorly known origins space and time. Recently, † Cryptovaranoides microlanius from the Late Triassic of United Kingdom was described as oldest crown squamate. If true, this result would push back origin all major lizard clades by 30–65 Myr suggest that divergence times for estimated using genomic morphological data are grossly inaccurate. Here, we use computed tomography scans expanded phylogenetic datasets to re-evaluate affinities other putative early squamates. We robustly reject squamate , instead resolve a potential member bird crocodylian total clade, Archosauromorpha. Bayesian evidence dating supports Jurassic squamates, not recently suggested. highlight how features traditionally linked lepidosaurs fact widespread across reptiles. Our study reaffirms importance critically choosing constructing appropriate taxon sampling test problematic fossils calibrate Tree Life.

Language: Английский

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