A comprehensive phylogenetic analysis on early ornithischian evolution

Journal of Systematic Palaeontology, Journal Year: 2024, Volume and Issue: 22(1)

Published: June 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.

Language: Английский

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Cranial and postcranial anatomy of a juvenile baurusuchid (Notosuchia, Crocodylomorpha) and the taxonomical implications of ontogeny

The Anatomical Record, Journal Year: 2024, Volume and Issue: unknown

Published: March 1, 2024

Abstract Baurusuchidae comprises a clade of top‐tier terrestrial predators and are among the most abundant crocodyliforms found in Adamantina Formation, Bauru Basin, Brazil (Campanian‐Maastrichtian). Here, we provide detailed description cranial postcranial osteology myology complete juvenile baurusuchid to date. Although preservation individuals is somewhat rare, previously reported occurrences egg clutches, yearling individual, larger, but skeletally immature specimens, comprise unique opportunity track anatomical changes throughout their ontogenetic series. Its anatomy was resolved with aid three‐dimensional model generated by acquisition computed tomography data, its inferred adductor mandibular musculature compared that mature specimens order assess possible shifts. A subsequent phylogenetic analysis included scoring Gondwanasuchus scabrosus , smallest species known date, evaluate relations relative juvenile. We find considerable differences between juveniles adults concerning skull ornamentation muscle development, which might indicate niche partitioning, also evidence G. corresponds young semaphoront lacking features.

Language: Английский

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Diving dinosaurs? Caveats on the use of bone compactness and pFDA for inferring lifestyle

PLoS ONE, Journal Year: 2024, Volume and Issue: 19(3), P. e0298957 - e0298957

Published: March 6, 2024

The lifestyle of spinosaurid dinosaurs has been a topic lively debate ever since the unveiling important new skeletal parts for Spinosaurus aegyptiacus in 2014 and 2020. Disparate lifestyles this taxon have proposed literature; some argued that it was semiaquatic to varying degrees, hunting fish from margins water bodies, or perhaps while wading swimming on surface; others suggest fully aquatic underwater pursuit predator. various proposals are based equally disparate lines evidence. A recent study by Fabbri coworkers sought resolve matter applying statistical method phylogenetic flexible discriminant analysis femur rib bone diameters microanatomy metric called global compactness. From their analyses datasets wide range extant extinct taxa, they concluded two ( S . , Baryonyx walkeri ) were submerged “subaqueous foragers,” whereas third Suchomimus tenerensis remained terrestrial We performed thorough reexamination datasets, analyses, methodological assumptions which those conclusions based, reveals substantial problems each these areas. In exemplar we found unsupported categorization lifestyle, inconsistent inclusion exclusion inappropriate choice taxa independent variables. also explored effects uncontrolled sources variation estimates compactness arise biological factors measurement error. ability draw quantitative is limited when represented single data points with potentially large intrinsic variability. results our show low accuracy applied distributions do not meet fundamental method. These findings only invalidate particular et al but implications future uses paleontology.

Language: Английский

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Macroevolutionary patterns in the pelvis, stylopodium and zeugopodium of megalosauroid theropod dinosaurs and their importance for locomotor function

Royal Society Open Science, Journal Year: 2023, Volume and Issue: 10(8)

Published: Aug. 1, 2023

During the Mesozoic, non-avian theropods represented one of most successful clades globally distributed, with a wide diversity forms. An example is clade Megalosauroidea, which included medium- to large-bodied Here, we analyse macroevolution locomotor system in early Theropoda, emphasizing Megalosauroidea. We scored

Language: Английский

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Prey size and ecological separation in spinosaurid theropods based on heterodonty and rostrum shape

The Anatomical Record, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 28, 2024

Members of the dinosaur clade Spinosauridae had numerous traits attributed to feeding in or around water, and their apparatus has often been considered analogous modern crocodylians. Here we quantify craniodental morphology compare it Crocodylia. We measured from spinosaurid crocodylian skeletal material area alveoli as a proxy for tooth size determine size-heterodonty. Geometric morphometrics were also conducted on crowns bearing regions skull. Spinosaurids overall relatively large alveoli, both they, crocodylians, isolated enlarged alveoli. Spinosaurines along caudal dentary that baryonychines lacked, which instead additional positions. Size-heterodonty was positively allometric, spinosaurids overlapped with generalist/macro-generalist crocodylians similar sizes. Spinosaurid crown shape morphologies certain slender-longirostrine yet lacked molariform distal typical most rostra mandibles deep undulating margins correlating local sizes, may indicate developmental constraint. particularly long concavity rosette anterior cranial teeth, corresponding bulbous rostral dentary. The well suited quickly striking creating punctures, but not cutting flesh durophagy. jaws interlocked secure prey move deeper into mouth. probably did little oral processing, spinosaurines could have processed vertebrates. Overall, there is no indication restricted fish small aquatic prey.

Language: Английский

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Mandibular force profiles and tooth morphology in growth series of Albertosaurus sarcophagus and Gorgosaurus libratus (Tyrannosauridae: Albertosaurinae) provide evidence for an ontogenetic dietary shift in tyrannosaurids¹

Canadian Journal of Earth Sciences, Journal Year: 2021, Volume and Issue: 58(9), P. 812 - 828

Published: Jan. 26, 2021

The albertosaurines Albertosaurus sarcophagus and Gorgosaurus libratus are among the best represented tyrannosaurids, known from nearly complete growth series. These specimens provide an opportunity to study mandibular biomechanical properties tooth morphology infer changes in feeding behaviour bite force through ontogeny tyrannosaurids. Mandibular profiles reveal that symphyseal region of is consistently stronger bending than mid-dentary region, indicating anterior extremity jaws played important role prey capture handling ontogeny. was better adapted withstand torsional stresses most non-avian theropods, but not extent seen Tyrannosaurus rex, suggesting albertosaurine may have involved less bone crushing or perhaps relatively smaller rex. constancy these at all stages indicates although maintained a similar strategy ontogeny, size/type had change between juvenile mature individuals. This ontogenetic dietary shift likely happened when individuals reached length ∼58 cm, size which teeth ziphodont incrassate shape begins increase exponentially. fact large were capable generating forces equivalent similar-sized tyrannosaurines suggests no significant differences jaw-closing musculature existed two clades powerful rex result its body rather unique adaptations related specialized ecology.

Language: Английский

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Exceptionally preserved stomach contents of a young tyrannosaurid reveal an ontogenetic dietary shift in an iconic extinct predator

Science Advances, Journal Year: 2023, Volume and Issue: 9(49)

Published: Dec. 8, 2023

Tyrannosaurids were large carnivorous dinosaurs that underwent major changes in skull robusticity and body proportions as they grew, suggesting occupied different ecological niches during their life span. Although adults commonly fed on dinosaurian megaherbivores, the diet of juvenile tyrannosaurids is largely unknown. Here, we describe a remarkable specimen Gorgosaurus libratus preserves articulated hindlimbs two yearling caenagnathid inside its abdominal cavity. The prey selectively dismembered consumed separate feeding events. This predator-prey association provides direct evidence an ontogenetic dietary shift tyrannosaurids. Juvenile individuals may have hunted small young until reached size when, to satisfy energy requirements, transitioned megaherbivores. both mesopredator apex predator roles span, factor been key evolutionary success.

Language: Английский

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Estimation of maximum body size in fossil species: A case study using Tyrannosaurus rex

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(7)

Published: July 1, 2024

Among extant species, the ability to sample extremes of body size-one most useful predictors an individual's ecology-is highly unlikely. This improbability is further exaggerated when sampling already incomplete fossil record. We quantify likelihood uppermost limits size in record using

Language: Английский

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The macroecology of Mesozoic dinosaurs

Biology Letters, Journal Year: 2024, Volume and Issue: 20(11)

Published: Nov. 1, 2024

Dinosaurs thrived for over 160 million years in Mesozoic ecosystems, displaying diverse ecological and evolutionary adaptations. Their ecology was shaped by large-scale climatic biogeographic changes, calling a ‘deep-time’ macroecological investigation. These factors include temperature fluctuations the break up of Pangaea, influencing species richness, diversity history. Recent improvements dinosaur fossil record have enabled studies their responses to tectonic, geographic shifts. Trends diversity, body size reproductive traits can now be analysed using quantitative approaches like phylogenetic comparative methods, machine learning Bayesian inference. patterns sometimes align with, but also deviate from, first-order rules (e.g. species–area relationship, latitudinal biodiversity gradient, Bergmann’s rule). Accurate reconstructions palaeobiodiversity niche partitioning require ongoing taxonomic revisions detailed anatomical descriptions. Interdisciplinary research combining sedimentology, geochemistry palaeoclimatology helps uncover environmental conditions driving Fieldwork under-sampled regions, particularly at extremes, is crucial understanding spatial heterogeneity ecosystems across planet. Open science initiatives online databases play key role advancing this field, enriching our deep-time processes, offering new insights into macroecology its broader implications.

Language: Английский

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Ontogenetic dietary shifts in North American hadrosaurids (Dinosauria: Ornithischia)

Cretaceous Research, Journal Year: 2022, Volume and Issue: 135, P. 105177 - 105177

Published: Feb. 23, 2022

Ontogenetic niche shifts, the phenomenon whereby animals change their resource use with growth, were probably widespread in dinosaurs, but most studies of duck-billed dinosaur ontogeny have so far focused mainly on development cranial ornamentation. Here, we quantify allometry 13 ecomorphological variables skull and examine tooth microwear a sample North American hadrosaurids to better understand ecological functioning growth. Our results indicate that, consistent Jarman-Bell principle relating body size fibre intake feeding selectivity, juvenile relatively more selective than adult counterparts subsisted softer, low-growing browse cropped using lateral rotations neck. Chewing movements jaw did not differ greatly between growth stages. findings invite further investigation ontogenetic hadrosauromorphs broadly, possible role shifts structuring Late Cretaceous herbivore communities.

Language: Английский

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