Intraskeletal histovariability and skeletochronology in an ornithopod dinosaur from the Maestrazgo Basin (Teruel, Spain)

Journal of Anatomy, Год журнала: 2025, Номер unknown

Опубликована: Янв. 28, 2025

Abstract Ornithopods are an extinct group of dinosaurs that were particularly abundant and diverse in the Cretaceous Iberian Peninsula, whose abundance Maestrazgo Basin has allowed numerous taxa to be identified over last decade. Many these fossil remains still taxonomically indeterminate require a more detailed study on both macroscopic microscopic scale. In this contribution, osteohistological analysis is carried out partial skeleton—composed five incomplete vertebrae, two dorsal ribs, ischium, fibula, tibia—found province Aliaga (Teruel, NE Spain). We progressive slowdown tissue apposition variation type growth marks generated every bone, allowing precise identification ontogenetic stage specimen as subadult individual. The skeletochronological correlation between different elements also suggests reached sexual maturity at around seven years age died nine twelve age. Likewise, usefulness three‐front model proven for first time ornithopod dinosaur, tool analysing histology expressed by bone single inferring their potential. Comparison with other reveals great variability each element shows depending taxon analysed, which prevents us from determining suitable studying skeletochronology any taxon.

Язык: Английский

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Skull morphology and histology indicate the presence of an unexpected buccal soft tissue structure in dinosaurs

Journal of Anatomy, Год журнала: 2025, Номер unknown

Опубликована: Март 21, 2025

Unlike mammals, reptiles typically lack large muscles and ligaments that connect the zygoma to mandible. Dinosaur craniomandibular soft tissue reconstructions, often based on rationale of extant phylogenetic bracketing, follow this general rule. However, descending flanges from zygomata hadrosaurs, heterodontosaurids, psittacosaurids have been used argue for a masseter-like muscle in these dinosaur taxa. We examined dinosauriform skulls osteological indicators connective entheses mandible, subsequently sectioned 10 specimens histological evidence. Osteological were found most sampled dinosauriforms, which range rugosities processes, morphologically resemble known muscular ligamentous entheses. Similarly, rugose features oriented towards mandible many having previously interpreted as adductor mandibulae group. Serial sectioning ceratopsid, hadrosaurid, tyrannosaurid jugal surangular reveals an external cortex rich collagen fibres, strongly resembling entheseal fibres. Jugal fibres are usually ventrally surangular, hadrosaurids tyrannosaurids parallel macroscopic striations surfaces flange. Histological sections chicken buccal regions show similar attachments jugomandibular ligament musculature hypothesise strong structure bridging dinosaurs, termed 'exoparia'. This structure's size proximity joint would be advantageous stabilising relative cranium during jaw movement, particularly dinosaurs thought process their masticate. A or identity exoparia cannot determined with available data, but shape zygomatic more consistent attachment. Possible antecedents non-dinosauriform archosaurs derivations modern birds may exist, homology is currently unknown. These results highlight complex evolution caution against simplified model-based approaches reconstruction ignore contrasting signals.

Язык: Английский

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Evidence of large-sized ankylopollexian dinosaurs (Ornithischia: Iguanodontia) in the Upper Jurassic of Portugal

Journal of Systematic Palaeontology, Год журнала: 2025, Номер 23(1)

Опубликована: Апрель 2, 2025

Язык: Английский

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Ornitópodos basales del centro-sur de Chubut, Patagonia central: Consideraciones evolutivas, paleohistológicas y paleoambientales

Publicación Electrónica de la Asociación Paleontológica Argentina, Год журнала: 2025, Номер unknown, С. 31 - 48

Опубликована: Апрель 10, 2025

En el centro-sur de la Provincia Chubut se exponen excelentes afloramientos rocas sedimentarias edad cretácica que conforman principal relleno cuenca del Golfo San Jorge. Dentro esta destacan por su abundancia vertebrados fósiles, Formación Bajo Barreal (Cenomaniano temprano–Turoniano tardío) y Lago Colhué Huapi (Coniaciano–Maastrichtiano). Aunque registro está mayormente dominado dinosaurios saurisquios, hallazgos fósiles ornitisquios, específicamente ornitópodos, han incrementado en los últimos años. contribución pretende ampliar conocimiento ornitópodos basales Notohypsilophodon comodorensis Sektensaurus sanjuanboscoi provenientes las formaciones Huapi, respectivamente. También, primera vez, abordan describen aspectos sobre paleohistología ambos ornitópodos. Asimismo, con evidencias cuentan al momento a espera nuevos estudios resuelvan mejor relaciones sistemáticas base Ornithopoda, sugiere elasmarios habrían originado este Gondwana, probablemente durante Cretácico temprano, posteriormente dispersado oeste dicho supercontinente, donde alcanzaron tamaños corporales mayores. Por último, menos Patagonia central, observa una selección ambiente entre (elasmarios) derivados (hadrosáuridos). Los primeros desarrollado ambientes tierra adentro climas cierta estacionalidad, mientras hadrosáuridos seleccionado cercanos mar un clima más homogéneo.

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A Review of Nanosaurus agilis Marsh and Other Small-Bodied Morrison Formation “Ornithopods”

Bulletin of the Peabody Museum of Natural History, Год журнала: 2025, Номер 66(1)

Опубликована: Апрель 25, 2025

Язык: Английский

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Exploring the diversity and disparity of rhabdodontomorph ornithopods from the Late Cretaceous European archipelago

Scientific Reports, Год журнала: 2025, Номер 15(1)

Опубликована: Апрель 30, 2025

The origin and early diversification of ornithopods, a major clade ornithischian dinosaurs, remain poorly understood, with conflicting phylogenetic hypotheses regarding rootward neornithischian relationships. Some topological stability is inferred near the basal divergence Iguanodontia, though ingroup relationships unclear. For instance, Rhabdodontidae, Late Cretaceous European ornithopods 'traditionally' considered to include eight nine species, presents significant taxonomic challenges. We explore diversity disparity Rhabdodon-lineage iguanodontians. assembled novel dataset comprising morphological morphometric data obtained from rhabdodontomorph dentaries, which are abundant, well-preserved in majority taxa, distinctive. Special attention given Rhabdodon septimanicus, known taxon upper Campanian lower Maastrichtian southern France, established based on particularly robust dentary bone that has been subjected interpretations. Our restudy specimen, combined multivariate assessment, shows this clear outlier among rhabdodontomorphs, providing basis for its assignment new genus, Obelignathus. Although further large-scale studies, especially detailed osteological descriptions, needed clarify significance certain our results indicate group exhibits greater than currently recognized, several sympatric taxa co-occurring, at least France possibly also Romania.

Язык: Английский

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New perspectives on body size and shape evolution in dinosaurs

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Год журнала: 2025, Номер unknown

Опубликована: Май 8, 2025

ABSTRACT Diversity in the body shapes and sizes of dinosaurs was foundational to their widespread success during Mesozoic era. The ability quantify size form reliably is therefore critical study dinosaur biology evolution. Body mass estimates for any given fossil animal are, theory, most informative when derived from volumetric models that account three‐dimensional entire body. In addition providing total mass, approaches can be used determine inertial properties specific segments overall distribution throughout body, each which are essential modelling interpretation form–function relationships associations with ecology. However, determination volumes taxa often subjective, may sensitive varied artistic inference. This highlights need an approach estimation segment systematically constrained by quantitative scaling between hard tissues fossilise soft only observable extant taxa. To this end, we recently published skeletal tissue factors CT data sauropsids estimate 52 non‐avian representing majority major clades plans. masses estimated range less than 200 g tiny avialan Yixianornis over 60 tonnes giant sauropod Patagotitan , currently largest known mostly complete remains. From our models, infer many previous reconstructions envelopes too small, were heavier estimates. Our generally overlap limb bone shaft dimensions, but considerable variability among clades. suggests different either differed volume ratios, or dimensions relative perhaps related differences locomotor dynamics postural also allowed us investigate variation proportions across a perspective grounded anatomical data, framing long‐standing hypotheses about form, function, behaviour context. For example, reconstructed disparity whole‐body centres reflects broad array postures clades, while lack strong positive allometry weight‐bearing corroborates studies suggesting decrease performance as increased.

Язык: Английский

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New insights into the phylogeny and skull evolution of stegosaurian dinosaurs: An extraordinary cranium from the European Late Jurassic (Dinosauria: Stegosauria)

Vertebrate Zoology, Год журнала: 2025, Номер 75, С. 147 - 171

Опубликована: Май 26, 2025

Abstract Stegosauria is an iconic clade of thyreophoran dinosaurs mainly characterized by two parasagittal rows osteoderms that extend from the neck to end tail. The fossil record stegosaurian cranial material remarkably fragmentary and scarce. This study describes most complete skull Europe proposes a new hypothesis for phylogenetic relationships stegosaurs. was recovered beds Villar del Arzobispo Formation (Upper Jurassic, Teruel, Spain) confidently referred Dacentrurus armatus . It provides valuable insights into anatomy this species enhances understanding evolution in Furthermore, diagnosis D. updated with identification autapomorphy. Stegosaurian nomenclature also revised. Maximum Parsimony has been applied analyse data matrix. Phylogenetic analyses suggest divided major clades: Huayangosauridae Stegosauridae. These support Isaberrysaura mollensis as stegosaur place it within Huayangosauridae, includes several Jurassic stegosaurs Asia. For first time, Mongolostegus exspectabilis included analysis, results which suggests lineage huayangosaurids or early-diverging stegosaurids persisted Asia until at least late Early Cretaceous. tree topologies challenge synonymization genera Stegosaurus Wuerhosaurus Moreover, concluded taxonomic re-evaluation Cretaceous Chinese necessary. Alcovasaurus longispinus Kentrosaurus aethiopicus are dacentrurines.

Язык: Английский

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A new small-bodied ankylosaurian dinosaur from the Upper Cretaceous of North Patagonia (Río Negro Province, Argentina)

Journal of Systematic Palaeontology, Год журнала: 2022, Номер 20(1)

Опубликована: Дек. 1, 2022

The most representative ankylosaurian remains from Argentina have been found in sediments of the Allen Formation (Campanian–Maastrichtian) Salitral Moreno, Río Negro Province. Several authors discussed identity and history these remains. In this study, we review all published material along with some new order to summarize knowledge about ankylosaurs. Previously includes a tooth, dorsal anterior caudal vertebrae, femur several osteoderms. include synsacral elements, partial anatomy synsacrum, mid-caudal vertebra, osteoderms, histology post-cervical support nodosaurid identification, as proposed previous descriptions Moreno material. Patagopelta cristata gen. et sp. nov. is ankylosaur characterized by presence unique cervical half-ring femoral anatomies, including high-crested lateral osteoderms half rings strongly developed muscular crest surface femur. ∼2 m body length estimated for very small an ankylosaur, comparable dwarf Struthiosaurus. We recovered within Nodosaurinae, related nodosaurids 'mid'-Cretaceous North America, contrasting topologies that Panoplosaurini (Late Cretaceous American nodosaurids). These results palaeobiogeographical context which Argentina, are part allochthonous fauna migrated into South America during late Campanian First Biotic Interchange.https://zoobank.org/urn:lsid:zoobank.org:pub:FBA24443-F365-49FD-A959-10D2848C2400

Язык: Английский

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An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America

PLoS ONE, Год журнала: 2023, Номер 18(6), С. e0286042 - e0286042

Опубликована: Июнь 7, 2023

Intensifying macrovertebrate reconnaissance together with refined age-dating of mid-Cretaceous assemblages in recent decades is producing a more nuanced understanding the impact Cretaceous Thermal Maximum on terrestrial ecosystems. Here we report discovery new early-diverging ornithopod, Iani smithi gen. et sp. nov., from Cenomanian-age lower Mussentuchit Member, Cedar Mountain Formation Utah, USA. The single known specimen this species (NCSM 29373) includes well-preserved, disarticulated skull, partial axial column, and portions appendicular skeleton. Apomorphic traits are concentrated frontal, squamosal, braincase, premaxilla, including presence three premaxillary teeth. Phylogenetic analyses using parsimony Bayesian inference posit as North American rhabdodontomorph based enlarged, spatulate teeth bearing up to 12 secondary ridges, maxillary lacking primary ridge, laterally depressed process jugal, posttemporal foramen restricted among other features. Prior discovery, neornithischian paleobiodiversity Member was primarily isolated teeth, only hadrosauroid Eolambia caroljonesa named remains. Documentation possible assemblage, along published reports an as-of-yet undescribed thescelosaurid, fragmentary remains ankylosaurians ceratopsians confirms minimum five, cohabiting clades earliest Late ecosystems America. Due poor preservation exploration Turonian–Santonian assemblages, timing extirpation Western Interior Basin is, yet, unclear. However, documents survival all major Early neornithischians (Thescelosauridae, Rhabdodontomorpha, Ankylopollexia) into dawn

Язык: Английский

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