A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution

Nature Communications, Journal Year: 2018, Volume and Issue: 9(1)

Published: Jan. 9, 2018

The Jurassic Yanliao theropods have offered rare glimpses of the early paravian evolution and particularly bird origins, but, with exception bizarre scansoriopterygids, they shown similar skeletal integumentary morphologies. Here we report a distinctive new theropod species bearing prominent lacrimal crests, bony ornaments previously known from more basal theropods. It shows longer arm leg feathers than Anchiornis tail asymmetrical vanes forming surface area even larger that in Archaeopteryx. Nanostructures, interpreted as melanosomes, are morphologically to organized, platelet-shaped organelles produce bright iridescent colours extant birds. indicates presence ornaments, feather colour flight-related features consistent proposed rapid character significant diversity signalling locomotor strategies near origins.

Language: Английский

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The oldestArchaeopteryx(Theropoda: Avialiae): a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria

PeerJ, Journal Year: 2018, Volume and Issue: 6, P. e4191 - e4191

Published: Jan. 26, 2018

The iconic primeval bird Archaeopteryx was so far mainly known from the Altmühltal Formation (early Tithonian) of Bavaria, southern Germany, with one specimen having been found in overlying Mörnsheim Formation. A new (the 12th skeletal specimen) earliest Tithonian Painten Schamhaupten (Bavaria) represents oldest representative genus. shows several interesting anatomical details, including presence a postorbital contact jugal, separate prefrontal and coronoid, opisthocoelous mid-cervical vertebrae. Based on observations specimen, we discuss problematic issues concerning Archaeopteryx, monophyly diagnosis genus, absence/presence sternum, position gastralia, variation morphometrics dental morphology that for genus Berlin, Eichstätt, Solnhofen, Munich, Daiting, Thermopolis, 11th, specimens can be referred to this high certainty. Maxberg is very probably also an based overall similarity, although none diagnostic characters evaluated ninth ('chicken wing') might but cannot any In comparison other paravians, distally thickened anterior pectoral ribs indicates rather large cartilagenous sternum present taxon. contrast non-opisthopubic theropods, opisthopubic taxa, such as many have posterior end gastral basket preserved at about half-length pubis, which reflect post-mortem collapse enlarged abdominal air sacs these taxa. Specimens show amount variation, both limb bones well dentition. respect latter aspect, tooth number, spacing, orientation, morphology, no two showing exact same pattern. significance unclear, possible explanations reach intraspecific (and possibly ontogenetic and/or sexual dimorphic) possibility represent 'species flock' due island speciation after initial dispersal into Solnhofen Archipelago.

Language: Английский

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Pennaraptoran Theropod Dinosaurs Past Progress and New Frontiers

Bulletin of the American Museum of Natural History, Journal Year: 2020, Volume and Issue: 440(1), P. 1 - 1

Published: Aug. 21, 2020

Language: Английский

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Dinosaur biodiversity declined well before the asteroid impact, influenced by ecological and environmental pressures

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: June 29, 2021

The question why non-avian dinosaurs went extinct 66 million years ago (Ma) remains unresolved because of the coarseness fossil record. A sudden extinction caused by an asteroid is most accepted hypothesis but it debated whether were in decline or not before impact. We analyse speciation-extinction dynamics for six key dinosaur families, and find a across dinosaurs, where diversification shifted to declining-diversity pattern ~76 Ma. investigate influence ecological physical factors, that was likely driven global climate cooling herbivorous diversity drop. latter due hadrosaurs outcompeting other herbivores. also estimate risk related species age during decline, suggesting lack evolutionary novelty adaptation changing environments. These results support environmentally well

Language: Английский

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Functional constraints on the number and shape of flight feathers

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(8)

Published: Feb. 12, 2024

As a fundamental ecological aspect of most organisms, locomotor function significantly constrains morphology. At the same time, evolution novel abilities has produced dramatic morphological transformations, initiating some significant diversifications in life history. Despite new fossil evidence, it remains unclear whether volant locomotion had single or multiple origins pennaraptoran dinosaurs and individual taxa are controversial. The powered flight modern birds involved exaptation feathered surfaces extending off limbs tail yet studies concerning potential pennaraptorans do not account for structure morphology wing feathers themselves. Analysis number shape remex rectrix across large dataset extant indicates that remiges rectrices degree primary vane asymmetry strongly correlate with ability revealing important functional constraints. Among these traits, phenotypic flexibility varies reflected by different rates at which changes evolve, such traits reflect ancestral condition, whereas others current function. While Mesozoic Microraptor have morphologies consistent birds, anchiornithines deviate providing strong evidence this clade was volant. results analyses support origin dinosaurian indicate early stages sampled currently available record.

Language: Английский

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A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight

PeerJ, Journal Year: 2019, Volume and Issue: 7, P. e7247 - e7247

Published: July 10, 2019

The last two decades have seen a remarkable increase in the known diversity of basal avialans and their paravian relatives. lack resolution relationships these groups combined with attributing behavior specialized taxa to base Paraves has clouded interpretations origin avialan flight. Here, we describe Hesperornithoides miessleri gen. et sp. nov., new theropod from Morrison Formation (Late Jurassic) Wyoming, USA, represented by single adult or subadult specimen comprising partial, well-preserved skull postcranial skeleton. Limb proportions firmly establish as occupying terrestrial, non-volant lifestyle. Our phylogenetic analysis emphasizes extensive taxonomic sampling robust character construction, recovering taxon most parsimoniously troodontid close Daliansaurus , Xixiasaurus Sinusonasus . Multiple alternative topologies similar degrees support, but proposals archaeopterygids, microraptorians, Rahonavis being closer Pygostylia than archaeopterygids unenlagiines are strongly rejected. All parsimonious results support hypothesis that each early clade was plesiomorphically flightless, raising possibility avian flight originated late Late Jurassic Early Cretaceous.

Language: Английский

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Ecophysiological steps of marine adaptation in extant and extinct non‐avian tetrapods

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2021, Volume and Issue: 96(5), P. 1769 - 1798

Published: April 26, 2021

ABSTRACT Marine reptiles and mammals are phylogenetically so distant from each other that their marine adaptations rarely compared directly. We reviewed ecophysiological features in extant non‐avian tetrapods representing 31 colonizations to test whether there is a common pattern across higher taxonomic groups, such as reptiles. can be roughly divided into aquatic haline adaptations, of which seems follow sequence three steps. In combination, these six categories exhibit five steps adaptation apply all clades except snakes: Step M1, incipient use resources; M2, direct feeding the saline sea; M3, water balance maintenance without terrestrial fresh water; M4, minimized travel loss feeding; M5, thermoregulation fur/plumage. Acquisition viviparity not included because no known case where evolved after tetrapod lineage colonized sea. A similar found snakes but with step (Step M3) lagging behind (haline S5 snakes), most likely unique method requires supply water. The same constraint may limit maximum body size fully snakes. Steps M4 M5 taxa associated skeletal mechanistically linked relevant features, allowing assessment some fossil tetrapods. identified four containing members reached outside stem whales, pinnipeds, sea cows turtles, namely Eosauropterygia, Ichthyosauromorpha, Mosasauroidea, Thalattosuchia, while M4: Saurosphargidae, Placodontia, Dinocephalosaurus , Desmostylia, Odontochelys . Clades reaching both extinct, appear have species diversity than those only M1 total number for earlier This suggests colonizers diversified greatly they resources, many lineages advanced Historical patterns suggest clade does advance unless early evolution clade. Intermediate forms before tend become extinct leaving descendants or evidence. makes it difficult reconstruct evolutionary history clades. last longer clades, sometimes more 100 million years.

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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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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Transformation of the pectoral girdle in pennaraptorans: critical steps in the formation of the modern avian shoulder joint

PeerJ, Journal Year: 2024, Volume and Issue: 12, P. e16960 - e16960

Published: Feb. 29, 2024

Important transformations of the pectoral girdle are related to appearance flight capabilities in Dinosauria. Previous studies on this topic focused mainly paravians yet recent data suggests evolved dinosaurs several times, including at least once among non-avialan paravians. Thus, fully explore evolution flight-related avian shoulder characteristics, it is necessary compare morphology more broadly. Here, we present information from pennaraptoran specimens preserving elements, all purportedly volant taxa, and extensively aspects joint. The results show that many modifications appear during basal pennaraptorans paravians, changes orientation coracoid body location articulation between furcula scapula. These suggest a change forelimb range motion preceded origin During early avialans, additional adaptive occur, such as separation scapula reduction articular surface these two bones, angle elongation coracoid. diversity morphologies types articulations joining scapula-coracoid each avialan lineage features parallel they independently refined capabilities. In ornithothoracines, glenoid fossa acrocoracoid approaches condition extant birds, suggesting greater stroke, which may represent acquisition improved powered capabilities, ground take-off. formation new Ornithuromorpha last step an osseous triosseal canal, indicate complete modern apparatus. morphological transitions equipped birds with motion, increased efficient muscular output while same time transmitting pressure being generated by ever powerful flapping movements way protect organs. driving factors functional adaptations transitional unclear although ontogenetic function observed provide excellent framework through can behavior Mesozoic pennaraptorans.

Language: Английский

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