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2021
Journal article
Paranasal sinus system and upper respiratory tract evolution in Mesozoic pelagic crocodylomorphs
Thalattosuchians were a predominately marine clade of Mesozoic crocodylomorphs, including semi-aquatic teleosauroid and obligately pelagic metriorhynchid subclades. Recent advances in our understanding of thalattosuchian endocranial anatomy have revealed new details of the evolutionary transition from terrestrial to marine to pelagic taxa. Paranasal sinuses, however, have received little attention. Herein, we...Cowgill, Thomas ; Young, Mark T ; Schwab, Julia A ; Walsh, Stig ; Witmer, Lawrence M …
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2021
Journal article
Rostral neurovasculature indicates sensory trade‐offs in Mesozoic pelagic crocodylomorphs
Metriorhynchoid thalattosuchians were a marine clade of Mesozoic crocodylomorphs that evolved from semi-aquatic, “gharial”-like species into the obligately pelagic subclade Metriorhynchidae. To explore whether the sensory and physiological demands of underwater life necessitates a shift in rostral anatomy, both in neurology and vasculature, we investigate the trigeminal innervation and potential...Bowman, Charlotte I W ; Young, Mark T ; Schwab, Julia A ; Walsh, Stig ; Witmer, Lawrence M …
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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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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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2017
Journal article
Open data and digital morphology
Over the past two decades, the development of methods for visualizing and analysing specimens digitally, in three and even four dimensions, has transformed the study of living and fossil organisms. However, the initial promise that the widespread application of such methods would facilitate access to the underlying digital data has... -
2016
Journal article
The braincase and neurosensory anatomy of an Early Jurassic marine crocodylomorph: Implications for crocodylian sinus evolution and sensory transitions
Modern crocodylians are a morphologically conservative group, but extinct relatives (crocodylomorphs) experimented with a wide range of diets, behaviors, and body sizes. Among the most unusual of these fossil groups is the thalattosuchians, an assemblage of marine-dwellers that transitioned from semiaquatic species (teleosaurids and kin) into purely open-ocean forms (metriorhynchids)...Brusatte, Stephen L ; Muir, Amy ; Young, M T ; Walsh, Stig A ; Steel, L …
tympanic sinuses, pneumaticity, crocodylomorph, thalattosuchian, sensory evolution, and neuroanatomy
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2016
Journal article
Best practices for digitally constructing endocranial casts: examples from birds and their dinosaurian relatives
The rapidly expanding interest in, and availability of, digital tomography data to visualize casts of the vertebrate endocranial cavity housing the brain (endocasts) presents new opportunities and challenges to the field of comparative neuroanatomy. The opportunities are many, ranging from the relatively rapid acquisition of data to the unprecedented ability...Balanoff, Amy M ; Bever, G S ; Colbert, Matthew W ; Clarke, Julia A ; Field, Daniel J …
brain, Aves, endocast, comparative neuroanatomy, and computed tomography