Osteology of the two-fingered oviraptorid Oksoko avarsan (Theropoda: Oviraptorosauria)

Zoological Journal of the Linnean Society, Год журнала: 2024, Номер 202(3)

Опубликована: Фев. 16, 2024

Abstract Oviraptorosaurs are among the most diverse and best-known extinct theropod groups. Their bizarre anatomy their social reproductive behaviour now well understood. Among oviraptorid subclade, two-fingered Oksoko avarsan is particularly well-represented. It known from several exquisite skeletons, preserving not only entire skeleton, but multiple stages through ontogeny, providing an exemplar for understanding of oviraptorids changes that skeletons experienced over lifetimes. Here I comprehensively describe osteology comment on its ontogenetic variation. Excellent preservation specimens provides unparalleled detail into oviraptorid, valuable context interpreting other oviraptorosaurs. Several observed to occur ontogeny relating robustness bones proportions there little evidence suggesting discrete features like cranial crest arose late in ontogeny. Instead, early development oviraptorids, internal connection with nasal passages pneumatic spaces, argue favour a role vocalization, perhaps alongside sexual display. Detailed anatomical data, those provided by avarsan, necessary help underpin ongoing research palaeobiology macroevolution Oviraptorosauria.

Язык: Английский

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Deinonychosaur trackways in southeastern China record a possible giant troodontid

iScience, Год журнала: 2024, Номер 27(5), С. 109598 - 109598

Опубликована: Апрель 24, 2024

The Longxiang tracksite (lower Upper Cretaceous, Shanghang Basin) includes twelve didactyl deinonychosaur tracks that fall into two morphologies, differentiated by both size and form. smaller (∼11 cm long) are referable to the ichnogenus

Язык: Английский

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Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae

Scientific Reports, Год журнала: 2024, Номер 14(1)

Опубликована: Июль 25, 2024

A new troodontid dinosaur, Hypnovenator matsubaraetoheorum gen. et sp. nov., is described based on an articulated postcranial skeleton recovered from the fluvial deposits of Albian Ohyamashimo Formation Sasayama Group in Tambasasayama City, Hyogo Prefecture, Japan. distinguished other troodontids by four autapomorphies and a combination additional features. Our phylogenetic analysis positions as oldest one most basal troodontines, forming clade with Gobivenator mongoliensis. The discovery suggests that small-bodied maniraptorans sleeping posture were common not only environments volcanic eolian events or alluvial systems but also systems. Geometric morphometric manual ungual phalanges shows I III exhibit considerable morphological variation are functionally similar, which differs those non-troodontine troodontids, reflecting transition motion within Troodontinae. has mosaic features pes related to cursoriality. This study reveals asymmetrical arctometatarsus occurred Albian, some changes, such shorter digit IV than non-ungual digits roller joints weakly ginglymoid articulation, arose during early Late Cretaceous.

Язык: Английский

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New information on Bonapartenykus (Alvarezsauridae: Theropoda) from the Allen Formation (middle Campanian-lower Maastrichtian) of Río Negro Province, Patagonia, Argentina clarifies the Patagonykinae body plan

PLoS ONE, Год журнала: 2025, Номер 20(1), С. e0308366 - e0308366

Опубликована: Янв. 30, 2025

Alvarezsauria is a group of morphologically distinctive, medium- to small-sized later-diverging coelurosaurian theropod dinosaurs, whose record ranges from the Late Jurassic Cretaceous. This clade had widespread distribution in Laurasia what now Europe, Asia, and North America, although there are also several Cretaceous taxa Gondwana Argentina that all belong family Alvarezsauridae. Although alvarezsaurid taxonomic diversity anatomical knowledge has expanded over last decade, internal phylogenetic relationships remain highly debated. In this contribution, we describe new material review previously reported specimens middle Campanian—lower Maastrichtian Allen Formation discovered at Salitral Ojo de Agua locality Río Negro province, Patagonia, Argentina. these were collected different times without precise original provenance information, here gathered X-ray diffraction data associated sediments suggests come same site stratigraphic level as holotype Bonapartenykus ultimus . Based on information morphological similarity considered specimens, tentatively refer them genus These newly referred add shed light body plan Patagonykinae by permitting more complete reconstruction neck, pectoral girdle, hindlimb, tail.

Язык: Английский

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Osteohistological analysis of metatarsals reveals new information on pathology and life history of troodontids from the Campanian Dinosaur Park Formation, Alberta, Canada

Journal of Anatomy, Год журнала: 2025, Номер unknown

Опубликована: Апрель 19, 2025

Abstract Troodontidae is a family of small‐bodied theropods known predominantly from Asia but are comparatively scarce in North America. In the Dinosaur Park Formation (DPF) Alberta, Canada, they isolated material, precluding taxonomic and ontogenetic precision for this clade. Previously never sampled histologically within DPF, here we attempt to fill gaps our knowledge about life histories clade formation by surveying metatarsals, which among most abundant identifiable troodontid elements DPF. We 11 metatarsals (three metatarsal IIs, three IIIs five IVs) varying sizes included pathological individuals describe microanatomy both healthy determine status each element graph their pattern growth. Osteohistology reveals that grew remodelled asymmetrically cortex, ceasing growth remodelling primarily along articular surfaces entheses. Pathological ranged displaying features response localised stress (chronic callus avulsion/chip fracture) extreme modification trauma inflammation at distal joint. Only latter appeared be related overall growth, suggesting condition either developed early stunted or another underlying cause was responsible resulting observed. Overall, tracking specimens there least two trajectories DPF differentiated timing major spurts plateaus. Whether represents sexual dimorphism, diversity, form variation warrants further investigation.

Язык: Английский

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Jaw biomechanics of Troodontidae and their implications for the palaeobiology of this lineage of bird-like theropod dinosaurs

Lethaia, Год журнала: 2025, Номер 58(1), С. 1 - 12

Опубликована: Фев. 20, 2025

Язык: Английский

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The body plan ofHalszkaraptor escuilliei(Dinosauria, Theropoda) is not a transitional form along the evolution of dromaeosaurid hypercarnivory

PeerJ, Год журнала: 2020, Номер 8, С. e8672 - e8672

Опубликована: Фев. 25, 2020

The dromaeosaurid theropod Halszkaraptor escuilliei is characterized by several unusual features absent in other paravians, part of which has been interpreted as diagnostic a novel lineage adapted to semiaquatic ecology. Recently, these evolutionary and ecological interpretations have challenged, claimed be transitional form between non-dromaeosaurid maniraptoriforms dromaeosaurids: following that reevaluation, its peculiar body plan would represent the retention maniraptoran plesiomorphies, lost among dromaeosaurids, not an adaptation This alternative scenario here carefully investigated tested. It shown most statements supporting this are based on misinterpretation anatomical traits bibliography. Once corrected, character state transition optimization over well-supported phylogenetic framework indicates large majority derived novelties acquired latter after divergence from last ancestor shared with eudromaeosaurs, thus maniraptoriform plesiomorphies. At least seven convergently spinosaurids, integrated adaptations: one reported for first time. amount morphological Halszkaraptorinae ancestral condition comparable those Microraptorinae Velociraptorinae. Among extant taxa, sawbills (Mergini, Anseriformes) show closest ecomorphological similarity inferred . halszkaraptorine bauplan confirmed amphibious specialization, does “transitional” stage along evolution dromaeosaurids.

Язык: Английский

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A fast-growing basal troodontid (Dinosauria: Theropoda) from the latest Cretaceous of Europe

Scientific Reports, Год журнала: 2021, Номер 11(1)

Опубликована: Март 1, 2021

Abstract A characteristic fauna of dinosaurs and other vertebrates inhabited the end-Cretaceous European archipelago, some which were dwarves or had unusual features likely related to their insular habitats. Little is known, however, about contemporary theropod dinosaurs, as they are represented mostly by teeth fragmentary fossils. new isolated metatarsal II, from latest Maastrichtian Spain (within 200,000 years mass extinction) may represent a jinfengopterygine troodontid, first reported Europe. Comparisons with theropods phylogenetic analyses reveal an autapomorphic foramen that distinguishes it all troodontids, supporting its identification genus species, Tamarro insperatus . Bone histology shows was actively growing subadult when died but have growth pattern in grew rapidly early ontogeny attained size quickly. We hypothesize could migrated Asia reach Ibero-Armorican island no later than Cenomanian during dispersal events.

Язык: Английский

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Bayesian analyses in phylogenetic palaeontology: interpreting the posterior sample

Palaeontology, Год журнала: 2020, Номер 63(6), С. 997 - 1006

Опубликована: Июль 25, 2020

Abstract Establishing hypotheses of relationships is a critical prerequisite for any macroevolutionary analysis, but different approaches exist achieving this goal. Amongst palaeontologists using morphological data the Bayesian approach increasingly preferred over parsimony, shift also alters way we think about samples trees. Here revisit stratigraphic congruence as comparator between and parsimony samples, in new visual context: treespace. Such spaces represent an ordination unique topologies that can be extended to create ‘landscape’ where altitude represents some comparative measure (here with stratigraphy). By co‐opting existing visualization tools applying them meta‐analysis 128 cladistic sets show there no consistent favouring either or according metrics, further empirical treespace visualizations suggest complex variety topological landscapes. We conclude by arguing treespaces should become standard exploratory tool phylogenetic analysis.

Язык: Английский

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Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies

Journal of Anatomy, Год журнала: 2020, Номер 236(5), С. 772 - 797

Опубликована: Фев. 5, 2020

Tetrapod limbs morphology is a reliable proxy of locomotor capacities. Beyond this, other aspects life habits, such as predation abilities, can also be relevant to determine main morphofunctional appendicular properties, which ultimately reflect compromise between different factors the biological role. Dromaeosauridae dinosaur clade belonging Theropoda, group bipedal predators. Dromaeosaurids represent an interesting study case, in hindlimbs have been proposed involved both locomotion and activity. A peculiar feature characterizing all dromaeosaurids modified second pedal digit, typically related predation. This theropod closely birds diversified during Cretaceous Period, mainly Northern Hemisphere (Laurasia). However, subclade dromaeosaurids, Unenlagiinae, was recently recognized for Gondwana. Nevertheless, there are morphological differences derived Laurasian (eudromaeosaurs) unenlagiines. Such observed proportions hindlimb bones presence subarctometatarsalian condition unenlagiines, characterized by proximally constricted metatarsal III. To evaluate function these divergent morphologies, we conducted morphometric analyses comparisons qualitative aspects, encompassing well taxa from groups, including extant birds. The former approach consisted two phylogenetic principal component analyses, one based on measurements hindlimb, focused lengths phalanges. first analysis drew unenlagiines close with long tibiae, slender metatarsi. Instead, eudromaeosaurs closer shorter wider showed that similar phalangeal proportions, elongation distal phalanx digit II could increased force generated this predatory tool autopodium. This, together metatarsus, marked hinge-like articular surfaces metatarsals phalanges, possibly allowed exert great gripping strength hunt large prey. Conversely, longer subarctometatarsus, less well-marked hinge joints gave them greater cursorial Additionally, fast movements smaller elusive Thus, distinctive evolutionary pathways dromaeosaurid clades seem influenced particular specializations each lineages.

Язык: Английский

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