Re-evaluation of the Bahariya Formation carcharodontosaurid (Dinosauria: Theropoda) and its implications for allosauroid phylogeny

PLoS ONE, Journal Year: 2025, Volume and Issue: 20(1), P. e0311096 - e0311096

Published: Jan. 14, 2025

The first partial skeleton of a carcharodontosaurid theropod was described from the Egyptian Bahariya Oasis by Ernst Stromer in 1931. referred specimen to species Megalosaurus saharicus , originally on basis isolated teeth slightly older rocks Algeria, under new genus name Carcharodontosaurus . Unfortunately, almost all material Oasis, including destroyed during World War II. In 1996, relatively complete cranium similar aged Morocco and designated neotype 2007. However, due destruction original material, comparisons fossils have so far only been done cursorily. A detailed reexamination available information carcharodontosaurid, previously undescribed photograph exhibited specimen, reveals that it differs Moroccan numerous characters, such as development emargination antorbital fossa nasals, presence horn-like rugosity nasal, lack dorsoventral expansion lacrimal contact frontals, relative enlargement cerebrum. referability Algerian M is found be questionable, designation for C accepted here consideration ICZN Atricle 75, both compares more favorably originates locality closer type locality. species, Tameryraptor markgrafi gen. et sp. nov, proposed taxon. theropods Kem Group are thus not closely related thought, faunal similarities between these two strata need further examination.

Language: Английский

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Paleoneurology of the iguanodontian Fostoria dhimbangunmal from the mid-Cretaceous of Australia

Journal of Paleontology, Journal Year: 2025, Volume and Issue: unknown, P. 1 - 9

Published: March 19, 2025

Abstract Insights into the paleoneurology and endocranial anatomy of ornithopod dinosaurs come largely from Northern Hemisphere taxa. The recently described non-hadrosaurid iguanodontian Fostoria dhimbangunmal Cenomanian eastern Australia includes a partial skull that offers novel insights its (i.e., cavity housing brain). Here, we describe F . based on digital cranial endocast obtained computed tomography. is mostly complete; however, it diagenetically dorsoventrally compressed ventral limits are not preserved. generally consistent with other iguanodontians, including well-developed olfactory apparatus, suggesting good sense smell. In contrast to hadrosaurids some possesses ancestral flexure condition, in which pontine angles subequal. cerebrum makes up significant portion volume; cerebral hemispheres as enlarged or bulbous seen hadrosaurids. forebrain did fill braincase same extent A distinct vacuity supraoccipital may represent new autapomorphy. This study provides first neuroanatomy an Australian dinosaur.

Language: Английский

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Ontogenetic Changes in Endocranial Anatomy in Gorgosaurus libratus (Theropoda: Tyrannosauridae) Provide Insight Into the Evolution of the Tyrannosauroid Endocranium

The Journal of Comparative Neurology, Journal Year: 2025, Volume and Issue: 533(5)

Published: April 28, 2025

ABSTRACT Over the past two decades, increased accessibility to computed tomography (CT) scanners has greatly facilitated documentation of endocranium in numerous extinct theropod taxa. However, most these studies have focused on morphology mature individuals, thus changes or variation through ontogeny theropods remains largely unknown. The current study sheds light endocranial anatomy eutyrannosaurian tyrannosauroid, Gorgosaurus libratus , both an ontogenetic and evolutionary context. Based CT scans six braincases, including those recently discovered juvenile we virtually reconstruct describe for a growth series G. . Despite considerable skull architecture, relatively few occurred These include subtle increase length hindbrain region endocast inflation tympanic sinus diverticula adults relative juveniles. Among significant is decrease distinctiveness brain endocasts as mature. exhibit better defined cerebral hemispheres, optic lobes, cerebella than larger more individuals. This suggests closer correspondence between tyrannosaurids, indicating individuals provides accurate representation structure its regions displays mix basal archosaurian traits derived coelurosaurian traits. More primitive features large olfactory bulbs tracts, posteroventrally oriented long axis cerebrum, posteriorly positioned whereas prominent flexure, somewhat enlarged cerebellum that at least partially separates left right lobes. An understanding acquisition such leading avian may be further elucidated via (more reflective structure/organization various regions) earlier‐diverging (e.g., Allosauroidea, Megalosauroidea, Coelophysoidea).

Language: Английский

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A proxy for brain‐to‐endocranial cavity index in non‐neornithean dinosaurs and other extinct archosaurs

The Journal of Comparative Neurology, Journal Year: 2024, Volume and Issue: 532(3)

Published: March 1, 2024

Abstract Although the brain fills nearly entire cranial cavity in birds, it can occupy a small portion of crocodilians. The lack data regarding volumetric correspondence between and hampers thorough assessments degree encephalization non‐neornithean dinosaurs other extinct archosaurs and, consequently, informed inferences their cognitive capacities. Existing suggest that, across extant archosaurs, endocranial doming volume intracranial nonneural components are inversely related. We build upon this information to develop an equation relating these two anatomical features archosaurs. rely on measurements endocast brain‐to‐endocranial (BEC) index relatives dinosaurs, namely, crurotarsans Caiman crocodilus , Crocodylus niloticus porosus ; paleognaths Struthio camelus Apteryx mantelli fowl Macrocephalon maleo Gallus gallus Meleagris gallopavo Phasianus colchicus Anas platyrhynchos . Applying representative endocasts from major clades we found that BEC varies about 0.6 ceratopsians thyreophorans around 0.7 ornithopods, pachycephalosaurians, sauropods, theropods. We, therefore, warn against use catch‐all value, like 0.5, instead encourage refinement adoption

Language: Английский

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The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus

Evolutionary Biology, Journal Year: 2022, Volume and Issue: 49(2), P. 156 - 179

Published: March 1, 2022

Language: Английский

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Two exceptionally preserved juvenile specimens of Gorgosaurus libratus (Tyrannosauridae, Albertosaurinae) provide new insight into the timing of ontogenetic changes in tyrannosaurids

Journal of Vertebrate Paleontology, Journal Year: 2021, Volume and Issue: 41(6)

Published: Oct. 1, 2021

Known from dozens of specimens discovered since the early 20th century, Gorgosaurus libratus has arguably contributed more than any other taxon to our understanding life history tyrannosaurids. However, juvenile material for this is rare. Here, we describe two small, articulated (skull lengths ca. 500 mm) that help advance knowledge anatomy and ontogeny tyrannosaurids in general. The new exhibit hallmark tyrannosaurid features, including long, low, narrow skulls, large circular orbits, absent or incipient cranial ornamentation, ziphodont dentition, an overall gracile skull frame. Comparison with various ontogenetic stages allows examination timing morphological changes occurred through relative Of particular note, larger Tyrannosaurus rex are found have experienced similar transformations at percent length known individuals each respective but different absolute body sizes biological ages, occurring a size older age Gorgosaurus. These results suggest dissociation between development Finally, recognition ontogenetically invariant characters makes it possible determine taxonomic identity previously misidentified specimens.

Language: Английский

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Paleoneurology of Non-avian Dinosaurs: An Overview

Springer eBooks, Journal Year: 2022, Volume and Issue: unknown, P. 267 - 332

Published: Nov. 22, 2022

Language: Английский

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New theropod dinosaur from the Lower Cretaceous of Japan provides critical implications for the early evolution of ornithomimosaurs

Scientific Reports, Journal Year: 2023, Volume and Issue: 13(1)

Published: Sept. 7, 2023

Ornithomimosauria consists of the ostrich-mimic dinosaurs, most which showing cursorial adaptations, that often exhibit features indicative herbivory. Recent discoveries have greatly improved our knowledge their evolutionary history, including divergence into Ornithomimidae and Deinocheiridae in Early Cretaceous, but early part history remains obscured because fossil are scarce Aptian-Albian sediments. In recent years, many isolated ornithomimosaur been recovered from Aptian Kitadani Formation Fukui, central Japan. These represent multiple individuals share some morphological common to them unknown other ornithomimosaurs, suggesting a monospecific accumulation new taxon. As result description phylogenetic analysis, is as genus species Tyrannomimus fukuiensis, earliest definitive deinocheirid complements understand Ornithomimosauria. Due its osteological similarity Tyrannomimus, taxon previously considered an tyrannosauroid based on fragmentary specimens, namely Aviatyrannis jurassica, may Upper Jurassic Europe, significantly expanding temporal biogeographic range This finding fills 20-million-year ghost lineage implied by presence oldest record Maniraptora Middle consistent with hypothesis was widespread before Pangaean breakup Kimmeridgian.

Language: Английский

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Anagenesis and the tyrant pedigree: A response to “Re-analysis of a dataset refutes claims of anagenesis within Tyrannosaurus-line tyrannosaurines (Theropoda, Tyrannosauridae)”

Cretaceous Research, Journal Year: 2024, Volume and Issue: 163, P. 105957 - 105957

Published: June 29, 2024

Taxonomic diversity in the derived tyrannosaurine Daspletosaurus has been hypothesized to represent a variety of evolutionary patterns by different authors. The recent description D. wilsoni, third species this genus, was proposed support paraphyly and participation its within single anagenetic lineage terminating at base clade formed Tyrannosaurus other gigantic tyrannosaurines (Tarbosaurus, Zhuchengtyrannus). However, reanalysis including additional data challenged interpretation, instead recovering as monophyletic sister group closest relatives, characterized several cladogenetic events. Here we show that incorporating further correcting erroneous interpretations relevant anatomical features overturns result. Using novel phylogenetic analysis specimens, recover paraphyletic Daspletosaurus, with genus forming successive taxa Tyrannosaurus-line tyrannosaurines. This result facilitates an interpretation currently recognized representing lineage, agreement stratigraphic distribution specimens qualitative range morphological variation observable wilsoni.

Language: Английский

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Paratympanic sinuses in juvenile Alligator

The Anatomical Record, Journal Year: 2022, Volume and Issue: 305(10), P. 2926 - 2979

Published: May 19, 2022

Abstract Crocodylia has an extensive epithelial pneumatic space in the middle ear, paratympanic sinus system. Although fossil and extant crocodylian systems have been studied recently using computed tomography (CT) three‐dimensional (3D) reconstruction data, due to soft tissue nature of system presence its surrounding structures, some boundaries, definitions each extension remain ambiguous. We describe comprehensive posthatched alligator enhanced CT data with 3D reconstructions. The are compared available discuss ontogenetic pattern alligator. introduce further divided entities based on their associated bony structures membrane clarify terminologies. then re‐visit potential homology Archosauria. Epithelial boundaries ventral portion from histological suggest that dual origin basioccipital diverticulum derived tympanic basicranial medially. boundary changes ontogeny suggests ear may function differently developmental stages. Lastly, a morphogenetic tree is constructed help future work comparative studies between crocodiles birds.

Language: Английский

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