Suchen
Suchergebnisse
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2023
Journal article
A revision of the ‘coelophysoid-grade’ theropod specimen from the Lower Jurassic of the Isle of Skye (Scotland )
The broadest diversification of early predatory dinosaurs is represented by the ‘coelophysoid-grade’ neotheropods, but their Hettangian–Sinemurian ( 191–201 Ma) record is scarce worldwide. More information is needed to shed light on the evolution of this dinosaur group after the end-Triassic mass extinction ( 201 Ma). Here we revisit the anatomy...Ezcurra, Martín D ; Marke, Daniel ; Walsh, Stig A ; Brusatte, Stephen L
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2022
Journal article
Middle Jurassic fossils document an early stage in salamander evolution
Salamanders are an important group of living amphibians and model organisms for understanding locomotion, development, regeneration, feeding, and toxicity in tetrapods. However, their origin and early radiation remain poorly understood, with early fossil stem-salamanders so far represented by larval or incompletely known taxa. This poor record also limits understanding of...Jones, Marc E H ; Benson, Roger B J ; Skutschas, Pavel ; Hill, Lucy ; Panciroli, Elsa …
AMPHIBIANS , PHYLOGENY , JURASSIC , SALAMANDER, and EVOLUTION
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2021
Journal article
The braincase and inner ear of ‘Metriorhynchus’ cf. ‘M.’ brachyrhynchus–implications for aquatic sensory adaptations in crocodylomorphs
During their long evolutionary history crocodylomorphs achieved a great diversity of body sizes, ecomorphotypes and inferred feeding ecologies. One unique group of crocodylomorphs are the thalattosuchians, which lived during the Jurassic and Cretaceous (ca. 191–125 Ma). They transitioned from shallow marine species, like teleosauroids, into fully pelagic forms with paddle...Schwab, Julia A ; Young, Mark T ; Herrera, Yanina ; Witmer, Lawrence M ; Walsh, Stig A …
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2021
Journal article
Ontogenetic variation in the crocodylian vestibular system
Crocodylians today live in tropical to subtropical environments, occupying mostly shallow waters. Their body size changes drastically during ontogeny, as do their skull dimensions and bite forces, which are associated with changes in prey preferences. Endocranial neurosensory structures have also shown to change ontogenetically, but less is known about the...Schwab, Julia A ; Young, Mark T ; Walsh, Stig A ; Witmer, Lawrence M ; Herrera, Yanina …
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2020
Journal article
Tempo and pattern of avian brain size evolution
Relative brain sizes in birds can rival those of primates, but large-scale patterns and drivers of avian brain evolution remain elusive. Here, we explore the evolution of the fundamental brain-body scaling relationship across the origin and evolution of birds. Using a comprehensive dataset sampling> 2,000 modern birds, fossil birds, and...Ksepka, Daniel T ; Balanoff, Amy M ; Smith, N Adam ; Bever, Gabriel S ; Bhullar, Bhart-Anjan S …
neurobiology, co-variation, encephalization, endocast, allometry, paleontology, and aves
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2020
Journal article
Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water
Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved...Schwab, Julia A ; Young, Mark T ; Neenan, James M ; Walsh, Stig A ; Witmer, Lawrence M …
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2011
Journal article
Halcyornis toliapicus (aves: Lower Eocene, England) indicates advanced neuromorphology in Mesozoic Neornithes
Our recent X-ray micro computer-tomographic (μCT) investigations of Prophaethon shrubsolei and Odontopteryx toliapica from the Lower Eocene London Clay Formation of England revealed the avian brain to have been essentially modern in form by 55 Ma, but that an important vision-related synapomorphy of living birds, the eminentia sagittalis of the...Walsh, Stig A ; Milner, Angela C
Eocene, eminentia sagittalis, London clay, Halcyornis toliapicus, endocranial cast, and brain evolution
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2012
Journal article
Virtual brain endocasts shed new light on the early evolution of modern birds (Neornithes)
This article is included in 'Program and Abstracts', 72nd Annual Meeting Society of Vertebrate Paleontology, October 17—20, 2012.Bourdon, Estelle ; Milner, A C ; Walsh, Stig A
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2009
Journal article
Inner ear anatomy is a proxy for deducing auditory capability and behaviour in reptiles and birds
Inferences of hearing capabilities and audition-related behaviours in extinct reptiles and birds have previously been based on comparing cochlear duct dimensions with those of living species. However, the relationship between inner-ear bony anatomy and hearing ability or vocalization has never been tested rigorously in extant or fossil taxa. Here, micro-computed...Walsh, Stig A ; Barrett, Paul M ; Milner, Angela C ; Manley, Geoffrey ; Witmer, Lawrence M
reptile, bird, hearing, papilla, basilar, duct, vocalization, and cochlear
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2010
Journal article
Sea dragons of Avalon
Tourists driving through the village2 of Street on their way to Glastonbury might well wonder at the representation of a skeleton on the road sign. Could this perhaps be a warning that this stretch of the A39 is a roadkill hotspot? I (Stig Walsh, once a local inhabitant) suspect that...Walsh, Stig A ; Taylor, Michael A
Street, ichthyosaur, plesiosaur, Somerset, Triassic, and Jurassic