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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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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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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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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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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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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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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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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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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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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
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Journal article
Exceptionally well-preserved early Eocene fossil reveals cranial and vertebral features of a stem group roller (Aves: Coraciiformes)
Three-dimensionally preserved skulls of small Paleogene land birds are very rare. Here, we describe a cranium and associated partial postcranial remains of an early Eocene stem group roller (Aves: Coraciiformes) from the London Clay of the Isle of Sheppey (England). The fossil shows features of the skull and vertebral column...Mayr, Gerald ; Walsh, Stig A
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Journal article
Comparative analysis of vestibular ecomorphology in birds
The bony labyrinth of vertebrates houses the semicircular canals. These sense rotational accelerations of the head and play an essential role in gaze stabilisation during locomotion. The sizes and shapes of the semicircular canals have hypothesised relationships to agility and locomotory modes in many groups, including birds, and a burgeoning...Benson, Roger B J ; Starmer-Jones, Ethan ; Close, Roger A ; Walsh, Stig A
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Journal article
A new Mississippian tetrapod from Fife, Scotland, and its environmental context
The Visean stage of the Mississippian was a time of rapid tetrapod diversification which marks the earliest appearance of temnospondyls, microsaurs and the limbless aïstopods. Tetrapod finds from this stage are very rare and only a dozen sites are known worldwide. Here we announce the discovery of a new Visean...Smithson, Timothy R ; Browne, Michael A E ; Davies, Sarah J ; Marshall, John E A ; Millward, David …
Mississippian, tetrapod, Spathi- cephalidae., Visean, and Asbian
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Journal article
A reassessment of the postcanine dentition and systematics of the tritylodontid Stereognathus (Cynodontia, Triltylodontidae, Mammaliamorpha) from the Middle Jurassic of the United Kingdom
Tritylodontidae was a successful advanced cynodont clade with a close relationship to mammals, but falling outside the clade Mammaliaformes. Stereognathus ooliticus was the first tritylodontid to be named and described in 1854, but since then no comprehensive description for this species has been produced. A second species, S. hebridicus, was...Panciroli, Elsa ; Walsh, Stig A ; Fraser, Nicholas C ; Brusatte, Stephen L ; Corfe, Ian
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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... -
Journal article
Floccular fossa size is not a reliable proxy of ecology and behaviour in vertebrates
The cerebellar floccular and parafloccular lobes are housed in fossae of the periotic region of the skull of different vertebrates. Experimental evidence indicates that the lobes integrate visual and vestibular information and control the vestibulo-ocular reflex, vestibulo-collic reflex, smooth pursuit and gaze holding. Multiple paleoneuroanatomy studies have deduced the behaviour...Ferreira-Cardoso, S ; Araújo, R ; Martins, N E ; Martins, G G ; Walsh, Stig A …
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Journal article
The dentary of Wareolestes rex (Megazostrodontidae): a new specimen from Scotland and implications for morganucodontan tooth replacement
The Middle Jurassic morganucodontan, Wareolestes rex, was previously known from only four isolated molars from Kirtlington, England. There has been debate over the position of the holotype tooth as an upper or lower molar. We describe a new Wareolestes specimen from the Kilmaluag Formation of Scotland: a partial left dentary...Panciroli, Elsa ; Benson, Roger B J ; Walsh, Stig A
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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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Journal article
Phylogenetic and environmental context of a Tournaisian tetrapod fauna
The end-Devonian to mid-Mississippian time interval has long been known for its depauperate palaeontological record, especially for tetrapods. This interval encapsulates the time of increasing terrestriality among tetrapods, but only two Tournaisian localities previously produced tetrapod fossils. Here we describe five new Tournaisian tetrapods (Perittodus apsconditus, Koilops herma, Ossirarus kierani, Diploradus austiumensis and Aytonerpeton microps)...Clack, Jennifer A ; Bennett, Carys E ; Carpenter, David K ; Davies, Sarah J ; Fraser, Nicholas C …
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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
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Journal article
A reappraisal of Cerebavis cenomanica (Aves, Ornithurae), from Melovatka, Russia
The evolution of the avian brain is of crucial importance to studies of the transition from non-avian dinosaurs to modern birds, but very few avian fossils provide information on brain morphological development during the Mesozoic. An isolated specimen from the Cenomanian of Melovatka in Russia was described by Kurochkin and...Walsh, Stig A ; Milner, Angela C ; Bourdon, Estelle
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Journal article
A lower jaw of Palaeoxonodon from the Middle Jurassic of the Isle of Skye, Scotland, sheds new light on the diversity of British stem therians
The Middle Jurassic was a key interval of mammalian evolutionary history that witnessed the diversification of the therian stem group. Great Britain has yielded a significant record of mammalian fossils from this interval, represented by numerous isolated jaws and teeth from the Bathonian of Oxfordshire and the Isle of Skye....Close, Roger A ; Davis, Brian M ; Walsh, Stig A ; Wolniewicz, Andrzej ; Friedman, Matt …
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Journal article
A new specimen of Baphetes from Nýřany, Czech Republic and the intrinsic relationships of the Baphetidae
'Loxomma'bohemicum from the Upper Carboniferous assemblage from Nýřany, Czech Republic, is a nomen dubium restricted to the type and only specimen. The new binomen Baphetes orientalis is created for a skull referred to Baphetes bohemicus by later authors. A previously undescribed baphetid specimen from Nýřany is referred to B. orientalis...Milner, Angela C ; Milner, Andrew R. ; Walsh, Stig A
Tetrapoda, Morphology, Carboniferous , and Phylogeny
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Journal article
Evolution of the brain and sensory organs in Sphenisciformes: new data from the stem penguin Paraptenodytes antarcticus
Penguins have undergone dramatic changes associated with the evolution of underwater flight and subsequent loss of aerial flight, which are manifest and well documented in the musculoskeletal system and integument. Significant modification of neurosensory systems and endocranial spaces may also be expected along this locomotor transition. However, no investigations of...Ksepka, D T ; Balanoff, Amy M ; Walsh, Stig A ; Revan, A ; Ho, A
Spheniscidae, palaeoneurology, computed tomography, and neuroanatomy
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Journal article
Ichthyosaurs from the Jurassic of Skye, Scotland
Fossils of Mesozoic vertebrates are rare in Scotland, particularly specimens of marine reptiles such as plesiosaurs and ichthyosaurs. We describe a suite of ichthyosaur fossils from the Early to Middle Jurassic of Skye, which to our knowledge are the first ichthyosaurs from Scotland to be described and figured in detail....Brusatte, Stephen L ; Young, Mark T ; Challands, Thomas James ; Clark, Neil D L ; Fischer, Valentin …
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Journal article
Avian cerebellar floccular fossa size is not a proxy for flying ability in birds
Extinct animal behavior has often been inferred from qualitative assessments of relative brain region size in fossil endocranial casts. For instance, flight capability in pterosaurs and early birds has been inferred from the relative size of the cerebellar flocculus, which in life protrudes from the lateral surface of the cerebellum....Walsh, Stig A ; Iwaniuk, Andrew N ; Knoll, Monja A ; Bourdon, Estelle ; Barrett, Paul M …