Terrestrialisation and the cranial architecture of tetrapods DOI Creative Commons
Ingmar Werneburg

Fossil record, Journal Year: 2024, Volume and Issue: 27(3), P. 473 - 497

Published: Dec. 27, 2024

Using four extinct land vertebrate species as examples, I discuss ontogenetic strategies well the potential influence of bite- and other external forces on formation skull. In principle, areas under biomechanical stress are strongly ossified, whereas regions with little or no show only weak ossification. this regard, all plates, arcades openings skull – even in that multi-fenestrated dinosaurs can be explained. trace changes feeding mode body posture at transition from semi-aquatic to fully terrestrial tetrapods position bite points. Through evolution, an increasing force is argued have a crucial new openings, such supratemporal antorbital fenestrae archosaurs, by changing direction flows The conquest was also associated appearance novel types behaviour inter- intraspecific combats. Horns cranial weapons were formed repeatedly, which shown alter construction when receiving forces. Changes biomechanics postcranial skeletal anatomy. Additionally, vice versa, neck muscles important impact differentiation tetrapod Finally, hypothesis provided for evolution temporal based considerations. argue synapsid (infrafenestral) morphotype ancestral amniotes related strong anterior mouth. Along reptilian lineage many parareptiles, captorhinids turtles fenestration repeatedly closed stiffening region response addition, upper opening evolved first diapsid (bifenestral) secondary. “triapsid” ceratopsid concentrated animal’s frill.

Language: Английский

New insights into the early morphological evolution of sea turtles by re-investigation of Nichollsemys baieri, a three-dimensionally preserved fossil stem chelonioid from the Campanian of Alberta, Canada DOI Creative Commons

J Menon,

Donald B. Brinkman, Guilherme Hermanson

et al.

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

Published: July 12, 2024

Abstract The early evolution of Pan-Chelonioidea (sea turtles) is poorly understood. This in part due to the rarity undeformed skulls definitive stem chelonioids. In this work, we redescribe holotype Nichollsemys baieri using µCT scans and segmentations skull. fossil best 3D preserved skull any Campanian sea turtle, includes partial “soft tissue” preservation. morphologically similar but clearly distinct from Toxochelys spp., both show a mosaic plesiomorphic derived chelonioid features. internal cranial anatomy documents presence characters that are absent such as loss epipterygoids rod-like shape rostrum basisphenoidale. Among numerous splenial bone, which was unnoticed before. An updated phylogenetic analysis retrieves non-protostegid slightly more crownward position than latiremis . Our phylogeny macrobaenids protostegids pan-chelonioids, find unorthodox results for dermochelyids. Thus, although provides important new insights into morphological turtles, much work remains be done. As completely specimen, included recent landmark-based dataset turtles. Morphospace reveals an intermediate between cryptodires crown Based on these data, also predict still capable neck retraction, constraining trait pan-chelonioids.

Language: Английский

Citations

2
Functional and Character Disparity Are Decoupled in Turtle Mandibles DOI Creative Commons
Jasper Ponstein, Guilherme Hermanson, Maren Jansen

et al.

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(11)

Published: Nov. 1, 2024

Turtles have high shape variation of their mandibles, likely reflecting adaptations to a broad variety food items and ingestion strategies. Here, we compare functional disparity measured by biomechanical proxies character discrete morphological characters. Functional disparities vary between clades ecological groups are thus decoupled. Comparisons with cranial also indicate decoupled patterns within the turtle skull. Exploration mandibular reveals that several configurations or state combinations can lead same feeding type (i.e., convergence) be achieved at low exhaustion (e.g., cryptodires). Dietary specialists show larger than generalists, but phylogenetically widespread generalist ecology leads signals in ecotype. Whereas generally shows phylogenetic signal, correspond dietary specializations, which may occur convergently across different groups. Despite this, individual measurements overlapping ranges ecogroups do not always conform expectations. Jaw opening closing advantages model trade-offs force transmission opening/closing speeds, turtles values try synthesize into "jaw types". Closing mechanical advantage retain levels anterior jaw end compared other pseudosuchians). This possibly explained as an evolutionary adaptation bite forces small head sizes.

Language: Английский

Citations

1
Terrestrialisation and the cranial architecture of tetrapods DOI Creative Commons
Ingmar Werneburg

Fossil record, Journal Year: 2024, Volume and Issue: 27(3), P. 473 - 497

Published: Dec. 27, 2024

Using four extinct land vertebrate species as examples, I discuss ontogenetic strategies well the potential influence of bite- and other external forces on formation skull. In principle, areas under biomechanical stress are strongly ossified, whereas regions with little or no show only weak ossification. this regard, all plates, arcades openings skull – even in that multi-fenestrated dinosaurs can be explained. trace changes feeding mode body posture at transition from semi-aquatic to fully terrestrial tetrapods position bite points. Through evolution, an increasing force is argued have a crucial new openings, such supratemporal antorbital fenestrae archosaurs, by changing direction flows The conquest was also associated appearance novel types behaviour inter- intraspecific combats. Horns cranial weapons were formed repeatedly, which shown alter construction when receiving forces. Changes biomechanics postcranial skeletal anatomy. Additionally, vice versa, neck muscles important impact differentiation tetrapod Finally, hypothesis provided for evolution temporal based considerations. argue synapsid (infrafenestral) morphotype ancestral amniotes related strong anterior mouth. Along reptilian lineage many parareptiles, captorhinids turtles fenestration repeatedly closed stiffening region response addition, upper opening evolved first diapsid (bifenestral) secondary. “triapsid” ceratopsid concentrated animal’s frill.

Language: Английский

Citations

1