A comprehensive phylogenetic analysis on early ornithischian evolution

Journal of Systematic Palaeontology, Год журнала: 2024, Номер 22(1)

Опубликована: Июнь 21, 2024

Resolving the evolutionary relationships of early diverging ('basal') ornithischian dinosaurs is a challenging topic in palaeontology, with multiple competing hypotheses on phylogenetic heterodontosaurids, 'hypsilophodontids', and other early-diverging forms. These cannot be directly compared because they are derived from differently constructed datasets (i.e. distinct samples taxa characters). This study aims to address these issues by revising combining into single analysis order create most comprehensive dataset for investigation ornithischians. A diphyletic model Dinosauria supported, silesaurs nesting as members Ornithischia. Heterodontosauridae resolved clade non-genasaurian ornithischians, rejecting potential relationship Marginocephalia. 'Hypsilophodontid' span neornithischian ornithopod stem, Thescelosauridae sister taxon Cerapoda. more restricted Ornithopoda composed five main clades: Hypsilophodontidae, Rhabdodontomorpha, Elasmaria, Dryosauridae Ankylopollexia. Hypsilophodontidae valid clade, reduced two European Barremian taxa. Rhabdodontomorpha does not contain Muttaburrasaurus originally proposed, but instead expands include North American formed Convolosaurus, Iani Tenontosaurus. Elasmaria contains all non-dryomorph Gondwanan ornithopods, its possessing body plans. New results comparison previous studies suggest that some 'true dryosaurids' various euiguanodontians may closely related either or Results group 'hypsilophodontids' larger clades, significantly reducing number extension ghost lineages throughout Neornithischia. clades also show degree endemism, different present at continents Late Cretaceous. new unifying works will provide framework future origins relations attempting find stability among hypotheses.

Язык: Английский

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Taxonomic, palaeobiological and evolutionary implications of a phylogenetic hypothesis for Ornithischia (Archosauria: Dinosauria)

Zoological Journal of the Linnean Society, Год журнала: 2022, Номер 196(4), С. 1273 - 1309

Опубликована: Авг. 24, 2022

Abstract The origin and evolutionary relationships of ornithischian dinosaurs are topics that have undergone a series substantial revisions. At present there several competing hypotheses concerning the relationship between Ornithischia other principal clades Dinosauria. Some posited tree topology within Dinosauria imply ‘ghost-lineage’ for (whose representatives make their first unambiguous appearance in Hettangian) extends through portion Triassic time. In contrast, placed conventionally dinosauromorph (stem-lineage Dinosauria) taxa clade Ornithischia. Recently, large-scale phylogenetic analysis recovered an array taxa, known as ‘silesaurids’, paraphyletic assemblage (referred to this article using informal terms silesaurs or silesaurians) on branch leading This latter hypothesis would account apparent absence ornithischians, because stem-lineage ornithischians (silesaurs article) exclusively Triassic. However, produced novel used dataset that, its original form, did not include all early (sensu lato), incorporate anatomical characters been suggested unite with dinosaurian (Theropoda Sauropodomorpha). Nor initial study go expand upon some important taxonomic, palaeobiological implications links addresses these issues by expansion re-analysis dataset. results find further support comprise grouping stem successive silesaur acquire anagenetically process culminates assembly what may be described ‘traditional’ ornithischian. overall consensus remains but little changed from analysis, despite addition new characters. To provide stability area preserve most relevant taxonomic names, we suggest revised framework is consistent topology. We retain name total-group (traditional stem-lineage), while resuscitate originally proposed Richard Owen, Prionodontia (= ‘coarse edged teeth’) containing only so-called traditional ‘bird-hipped’) dinosaurs. also erect Parapredentata more exclusive subclade intended clarity degree analyses data continue refine re-shape tree. presented represent stage our attempt establish dinosaur which character definitions scores agreed consistently.

Язык: Английский

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A new semi‐fossorial thescelosaurine dinosaur from the Cenomanian‐age Mussentuchit Member of the Cedar Mountain Formation, Utah

The Anatomical Record, Год журнала: 2024, Номер 307(12), С. 3717 - 3781

Опубликована: Июль 9, 2024

Thescelosaurines are a group of early diverging, ornithischian dinosaurs notable for their conservative bauplans and mosaic primitive features. Although abundant within the latest Cretaceous ecosystems North America, record is poor to absent in earlier assemblages, leaving large gap our understanding evolution, origins, ecological roles. Here we report new small bodied thescelosaurine-Fona herzogae gen. et sp. nov.-from Mussentuchit Member Cedar Mountain Formation, Utah, USA. Fona represented by multiple individuals, representing one most comprehensive skeletal assemblages bodied, diverging described from America date. Phylogenetic analysis recovers as earliest member Thescelosaurinae, minimally containing Oryctodromeus, all three species Thescelosaurus, revealing clade was well-established Cenomanian, distinct from, yet continental cohabitants with, sister clade, Orodrominae. To date, orodromines thescelosaurines have not been found together single American ecosystem, suggesting different habitat preferences or competitive exclusion. Osteological observations reveal extensive intraspecific variation across cranial postcranial elements, number anatomical similarities with shared semi-fossorial lifestyle.

Язык: Английский

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The phylogenetic relationships and evolutionary history of the armoured dinosaurs (Ornithischia: Thyreophora)

Journal of Systematic Palaeontology, Год журнала: 2023, Номер 21(1)

Опубликована: Янв. 1, 2023

The armoured dinosaurs (Thyreophora) were a significant component of Mesozoic terrestrial ecosystems, appearing in the earliest Jurassic and surviving until latest Cretaceous, fossils group have been found on all continents, including Antarctica. However, patchy fossil record highly modified anatomy has hindered reconstruction their evolutionary history. For example, relationships many early-diverging taxa are labile degree convergence between two major clades, Ankylosauria Stegosauria, difficult to assess. There never species-level phylogenetic analysis thyreophoran dinosaurs; recently, computational ability analyse such dataset did not exist and, consequently, interrelationships within debated. Here, we address these issues with new that includes majority named (340 characters, 91 taxa). This was analysed using equal- implied-weights parsimony Bayesian inference, further explored constraint trees partitioned datasets. Stratigraphical congruence used identify 'preferred tree' analyses reveal novel hypothesis for relationships. traditional ankylosaurian dichotomy is supported: instead, four distinct ankylosaur clades identified, long-standing 'traditional' clade Nodosauridae rendered paraphyletic. Ankylosauridae, Panoplosauridae, Polacanthidae Struthiosauridae morphotypes, typified by Euoplocephalus, Edmontonia/Panoplosaurus, Gastonia Struthiosaurus, respectively. Isaberrysaura an early stegosaur Scelidosaurus non-eurypodan. Many characters related feeding quadrupedality coincident diversification Eurypoda. Unstable generally incomplete but other better-known also unstable, suggesting need taxonomic revisions. Partitioned datasets show high postcrania osteoderm do contain strong signal.

Язык: Английский

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Early Jurassic origin of avian endothermy and thermophysiological diversity in dinosaurs

Current Biology, Год журнала: 2024, Номер 34(11), С. 2517 - 2527.e4

Опубликована: Май 15, 2024

A fundamental question in dinosaur evolution is how they adapted to long-term climatic shifts during the Mesozoic and when developed environmentally independent, avian-style acclimatization, becoming endothermic.

Язык: Английский

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Ornithopod tracks and bones: Paleoecology and an unusual evidence of quadrupedal locomotion in the Lower Cretaceous of eastern Iberia (Teruel, Spain)

Cretaceous Research, Год журнала: 2023, Номер 144, С. 105473 - 105473

Опубликована: Янв. 6, 2023

Язык: Английский

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Ornithischian dinosaurs in Southeast Asia: a review with palaeobiogeographic implications

Fossil record, Год журнала: 2023, Номер 26(1), С. 1 - 25

Опубликована: Янв. 10, 2023

Ornithischian dinosaurs have been discovered in Thailand, Laos, and Malaysia. These bird-hipped herbivores remain relatively rare by comparison with saurischian dinosaurs. In the Late Jurassic, stegosaurs basal neornithischians from Thailand showed similarities to Middle-Late Jurassic taxa China. Ornithischians appeared fossil record again during late Early Cretaceous (Aptian-Albian) of Laos. They are represented non-hadrosaurid iguanodontians ceratopsians. A few specimens reported poorly dated rocks Here, we illustrate diversity ornithischian assemblages Southeast Asia discuss their palaeobiogeographical implications.

Язык: Английский

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THE OSTEOLOGY OF THE HOLOTYPE OF THE BRITISH IGUANODONTIAN DINOSAURMANTELLISAURUS ATHERFIELDENSIS

Monographs of the Palaeontographical Society, Год журнала: 2023, Номер 177(665), С. 1 - 63

Опубликована: Янв. 2, 2023

Iguanodontian dinosaurs are known from Middle Jurassic to Late Cretaceous deposits worldwide and historically important because they include the first fossils be identified as giant extinct reptiles that later became dinosaurs. Due historical taxonomic practices fragmentary nature of many specimens, discoveries 19th century were referred Iguanodon with little appraisal, resulting in genus becoming something a 'wastebasket taxon'. Reinterpretations holotype specimens an step attempting understand evolutionary history iguanodontian Here, we redescribe Mantellisaurus atherfieldensis, one most complete British dinosaur Barremian/Aptian Isle Wight, UK, assess its phylogenetic position. We find atherfieldensis is valid taxon distinct based on three autapomorphies premaxilla, maxilla, scapula, resolves early diverging hadrosauroid styracosternan, representing ornithopods.

Язык: Английский

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Dental microwear texture analysis reveals a likely dietary shift within Late Cretaceous ornithopod dinosaurs

Palaeontology, Год журнала: 2023, Номер 66(6)

Опубликована: Ноя. 1, 2023

Abstract Dinosaurs were the dominant megaherbivores during Cretaceous when angiosperms, flowering plants, emerged and diversified. How herbivorous dinosaurs responded to increasing diversity of angiosperms is largely unknown due lack methods that can reconstruct diet directly from body fossils. We applied dental microwear texture analysis (DMTA), an approach quantifies microtopography diet‐induced wear marks on tooth surfaces, ornithopods, dinosaur clade includes taxa with most sophisticated masticatory system. found Late ornithopods have significantly rougher (DMT) compared pre‐Late DMT variation increased in hadrosaurids, a derived ornithopod clade. These changes indicate likely temporal dietary shift towards more abrasive foodstuffs within probably ingestion phytoliths (amorphous silica bodies plants). Phytoliths are main source rough modern herbivores, along exogenous dust grit, generally concentrated than other major plant groups. Our results show DMTA occlusal enamel surface be used diets dinosaurs, resolution superior conventional methods.

Язык: Английский

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Anatomical description and digital reconstruction of the skull of Jeholosaurus shangyuanensis (Dinosauria, Ornithopoda) from China

PLoS ONE, Год журнала: 2025, Номер 20(1), С. e0312519 - e0312519

Опубликована: Янв. 24, 2025

Ornithopod dinosaurs appeared during the Middle Jurassic, but it was in Lower Cretaceous they started their successful evolutionary history. Different phylogenies describing relationships of Ornithopoda are mostly based on cranial features, however there is a lack well-preserved and complete skulls for basal member clade, hampering our knowledge mode tempo these herbivorous dinosaurs. Here we describe YLSNHM 01942, skull juvenile neornithischian from Liaoning Province China. The specimen scanned with μCT scan, all elements were segmented extrapolated description. shows ventral deformation due to compression sediment, few rostral artificially added. attributed ornithopod Jeholosaurus shangyuanensis because presence large foramen quadratojugal, lacks nodular ornamentation postorbital jugal, herein interpreted as an ontogenetic feature. This, together disarticulation degree elements, suggest 01942 represents . endosseous labyrinth tentatively reconstructed, although neurocranial bones hampers its reconstruction. Thanks analysis previously undescribed inner (such prootics, exoccipital/ophistotic, basioccipital, basisphenoid), improve previous phylogenetical scoring J , perform adding Changmiania liaoningensis recently re-evaluated Ajkaceratops kozmai reports well-supported base Ornithopoda, C most ornithopod, resolved topology Nanosaurus agilis Changchunsaurus parvus Haya griva Yandusaurus hongheensis

Язык: Английский

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