Repeated Evolution of Divergent Modes of Herbivory in Non-avian Dinosaurs

Current Biology, Journal Year: 2019, Volume and Issue: 30(1), P. 158 - 168.e4

Published: Dec. 5, 2019

The importance of adaptation [1-4] versus organizational constraints [5-7] in shaping common macroevolutionary trends remains unclear [8]. fossil record is key to this problem, as it provides data on repetitive trait evolution between lineages [4, 8]. However, quantitative analyses investigating these dynamics with are rare Herbivory evolved multiple times within Mesozoic dinosaurs [9, 10], allowing analysis phenotypic responses dietary evolution. Whereas repeated patterns character acquisition [9] and functional changes [11-13] observed some herbivorous dinosaur clades, biomechanical studies resolve significant differences morphologically similar taxa [12-14]. previous have not accounted for phylogenetic non-independence (e.g., [13-16]) or been restricted individual clades [11, 12, 16]). Here, we use multivariate characters, a robust context, investigate pathways herbivory large sample non-avian dinosaurs. Results demonstrate solutions herbivory. Notably, two fundamentally different modes evolve independently times, morphofunctional the skull co-varying digestive strategy. These distinguish gut-processing sauropodomorphs theropods tending toward gracile crania low bite forces ornithischian exhibiting complexes associated extensive oral processing. Although convergence subsets common, them due imposed during early each group. This highlights hierarchical nature evolution, driving regions morphospace delimited by contingency.

Language: Английский

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The influence of juvenile dinosaurs on community structure and diversity

Science, Journal Year: 2021, Volume and Issue: 371(6532), P. 941 - 944

Published: Feb. 25, 2021

Despite dominating biodiversity in the Mesozoic, dinosaurs were not speciose. Oviparity constrained even gigantic to less than 15 kg at birth; growth through multiple morphologies led consumption of different resources each stage. Such disparity between neonates and adults could have influenced structure diversity dinosaur communities. Here, we quantified this effect for 43 communities across 136 million years seven continents. We found that megatheropods (more 1000 kg) such as tyrannosaurs had specific effects on community structure. Although herbivores spanned body size range, with lacked carnivores weighing 100 kg. demonstrate juvenile likely filled mesocarnivore niche, resulting reduced overall taxonomic diversity. The consistency pattern suggests ontogenetic niche shift was an important factor generating

Language: Английский

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Morphology and distribution of scales, dermal ossifications, and other non‐feather integumentary structures in non‐avialan theropod dinosaurs

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2022, Volume and Issue: 97(3), P. 960 - 1004

Published: Jan. 6, 2022

ABSTRACT Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in group theropod dinosaurs (Maniraptoriformes) include crown Aves. Squamous or scaly reptilian‐like skin is, however, considered plesiomorphic condition for theropods and more broadly. Here, we review morphology distribution non‐feathered integumentary structures non‐avialan theropods, covering squamous naked as well dermal ossifications. The record non‐averostran is limited to tracks, which ubiquitously show a tiny reticulate scales on plantar surface pes. This consistent also with younger averostran body fossils, confirm an arthral arrangement digital pads. Among averostrans, confirmed Ceratosauria ( Carnotaurus ), Allosauroidea Allosaurus , Concavenator Lourinhanosaurus Compsognathidae Juravenator Tyrannosauroidea Santanaraptor Albertosaurus Daspletosaurus Gorgosaurus Tarbosaurus Tyrannosaurus whereas ossifications consisting sagittate mosaic osteoderms restricted Ceratosaurus . Naked, non‐scale bearing found contentious tetanuran Sciurumimus ornithomimosaurians Ornithomimus ) possibly tyrannosauroids patagia scansoriopterygids Ambopteryx Yi ). Scales surprisingly conservative among compared some dinosaurian groups (e.g. hadrosaurids); preservation tegument most specimens hinders further interrogation. Scale patterns vary and/or within regions polarised, snake‐like ventral tail latter two genera. Unusual but uniformly distributed patterning occurs feature present only Few currently compelling evidence co‐occurrence feathers Sinornithosaurus although probably retained mani pedes many heavy plumage. Feathers filamentous appear have replaced integuments maniraptorans. Theropod skin, broadly, remains virtually untapped area study appropriation commonly used techniques other palaeontological fields holds great promise future insights into biology, taphonomy relationships these extinct animals.

Language: Английский

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Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs

Science, Journal Year: 2023, Volume and Issue: 379(6634), P. 811 - 814

Published: Feb. 24, 2023

In amniotes, the predominant developmental strategy underlying body size evolution is thought to be adjustments rate of growth rather than its duration. However, most theoretical and experimental studies supporting this axiom focus on pairwise comparisons and/or lack an explicit phylogenetic framework. We present first large-scale comparative analysis examining strategies size, focusing non-avialan theropod dinosaurs. reconstruct ancestral states mass in a taxonomically rich dataset, finding that contrary expectations, changes duration played nearly equal roles vast disparity theropods—and perhaps amniotes general.

Language: Английский

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The Evolution of the Maxillary Canal in Probainognathia (Cynodontia, Synapsida): Reassessment of the Homology of the Infraorbital Foramen in Mammalian Ancestors

Journal of Mammalian Evolution, Journal Year: 2019, Volume and Issue: 27(3), P. 329 - 348

Published: May 17, 2019

Language: Английский

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Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview

Frontiers in Earth Science, Journal Year: 2019, Volume and Issue: 6

Published: Feb. 12, 2019

Recent years witnessed the discovery of a great diversity early birds as well closely related non-avian theropods, which modified previous conceptions about origin and their flight. We here present review currently taxonomic composition main anatomical characteristics those theropod families with birds, aim to analyze discuss phylogenetic hypotheses that compete some topics dinosaur-bird transition. conclude troodontid affinities anchiornithines, dromaeosaurids microraptorians unenlagiids are dismissed in favor sister group relationships Avialae. After recodification topology TWiG scheme, results on large polytomy at base Pennaraptora. Regarding character evolution, we found that: 1) presence ossified sternum goes hand by uncinate processes; 2) folded forelimbs basal archosaurs indicates widespread distribution among reptiles, contradicting proposals forelimb folding driven propatagial associated tendons was exclusive avian lineage; 3) paravians avialans Archaeopteryx wings relatively wide, short rectricial feathers, rounded alar contour, having convex wing attack margin. These taxa exhibit restricted capabilities forelimbs, preserving hands flexor angles (respect radius/ulna) no lesser than 90º. In more derived instead, rectrices notably elongate angle described between forearm is much less 90º, indicating not only an increased capability but also variety beat movements during Because strong similarities pectoral girdle conformation ratites paravians, it possible infer were similar all these taxa, lacking complex dorsoventral excursion characteristic living neognathans.

Language: Английский

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Cranial morphology of the tanystropheid Macrocnemus bassanii unveiled using synchrotron microtomography

Scientific Reports, Journal Year: 2020, Volume and Issue: 10(1)

Published: July 24, 2020

The genus Macrocnemus is a member of the Tanystropheidae, clade non-archosauriform archosauromorphs well known for their very characteristic, elongated cervical vertebrae. Articulated specimens are from Middle Triassic Alpine Europe and China. Although multiple articulated known, description cranial morphology has proven challenging due to crushed preservation specimens. Here we use synchrotron micro computed tomography analyse specimen type species bassanii Besano Formation Monte San Giorgio, Ticino, Switzerland. skull virtually complete identify describe braincase palatal elements as atlas-axis complex first time. Moreover, add knowledge roof, rostrum hemimandible, reconstruct cranium M. in 3D using rendered models elements. circumorbital bones were found be similar those Prolacerta broomi Protorosaurus speneri. In addition, confirm palatine, vomer pterygoid tooth-bearing bones, but also observed heterodonty on palatine.

Language: Английский

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Origins of slow growth on the crocodilian stem lineage

Current Biology, Journal Year: 2023, Volume and Issue: 33(19), P. 4261 - 4268.e3

Published: Sept. 15, 2023

Language: Английский

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Cranial Anatomy of New Specimens of Saurornitholestes langstoni (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta

The Anatomical Record, Journal Year: 2019, Volume and Issue: 303(4), P. 691 - 715

Published: Sept. 9, 2019

ABSTRACT The holotype of the dromaeosaurid Saurornitholestes langstoni was described in 1978 on basis fewer than 30 associated cranial and postcranial bones a single individual from Dinosaur Provincial Park. Four additional partial skeletons were recovered Campanian (Upper Cretaceous) beds Alberta Montana over next 25 years, although reasonably complete remained elusive, virtually nothing known about skull. lack truly diagnostic material has been problematic, relationships to other dromaeosaurids have difficult resolve because incomplete knowledge its anatomy. In 2014, an almost skeleton, including skull, collected less kilometer where had found. Although similar body size Velociraptor , facial region skull is relatively shorter, taller, wider. nasals are pneumatic. premaxillary teeth distinctive, previously identified Park Formation as Zapsalis abradens can now be second tooth S . Morphology wear patterns suggest that these may specialized for preening feathers. Many traits define North American clade, Saurornitholestinae, distinct Asian clade includes (Velociraptorinae). This new information allows more evaluation systematic position within Dromaeosauridae supports suggestion at least two major faunal interchanges between Asia America during Cretaceous. Anat Rec, 303:691–715, 2020. © 2019 Association Anatomy

Language: Английский

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New theropod dinosaur teeth from the Middle Jurassic of the Isle of Skye, Scotland

Scottish Journal of Geology, Journal Year: 2019, Volume and Issue: 55(1), P. 7 - 19

Published: April 2, 2019

The Middle Jurassic is a largely mysterious interval in dinosaur evolution, as few fossils of this age are known worldwide. In recent years, the Isle Skye has yielded substantial record trackways, and more limited inventory body fossils, that indicate diverse fauna dinosaurs living around lagoons deltas. Comparatively little about predators these faunas (particularly theropod dinosaurs), their among rarest discoveries. We here report two new isolated teeth, from Valtos Sandstone Formation Lealt Shale Skye, which we visualized measured using high-resolution x-ray computed microtomographic scanning (µCT) identified via statistical phylogenetic analyses large comparative dental dataset. argue teeth most likely represent at least species – one small-bodied other large-bodied belonged to or several clades basal avetheropods (ceratosaurs, megalosauroids, allosauroids). These groups, were diversifying during would become dominant Late Jurassic, filled various niches food chain probably both on land lagoons. Supplementary material : Character lists, datasets, measurements available https://doi.org/10.6084/m9.figshare.c.4452533

Language: Английский

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