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, Journal Year: 2025, Volume and Issue: unknown

Published: April 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.

Language: Английский

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Osteohistology of the Maastrichtian, small‐bodied elasmosaurid Kawanectes lafquenianum (Sauropterygia; Plesiosauria)

Journal of Anatomy, Journal Year: 2025, Volume and Issue: unknown

Published: May 22, 2025

Abstract Plesiosauria is a clade of marine reptiles that thrived from the Late Triassic to end Cretaceous. Among plesiosaurs, elasmosaurids are particularly notable for their diverse body sizes. Small‐sized specimens Kawanectes lafquenianum exhibit fully closed neuro‐central sutures indicating skeletal maturity. To independently assess whether they indeed small‐bodied adults, we analysed paleohistology long bones three differently sized recovered La Colonia Formation, Chubut Province, Argentina. The microanatomy revealed differences in architectural organization hindlimbs and forelimbs, with humerus being highly remodelled as compared femur. Extensive secondary reconstruction propodials ribs suggests high rate calcium mobilization, perhaps related biomechanical stresses. Despite extensive all studied, primary bone tissue comprising parallel‐fibred lamellar was identified at outermost cortex, along an external fundamental system propodial one specimens. Overall osteohistology features indicate adult stage specimens, although it appears our sample represents individuals different levels Lines arrested growth were also registered, giving minimum age 11 14 years MPEF‐PV 1155 11545, respectively. These results indicated K. elasmosaurid (3.8 m–4.2 m length). Additionally, microstructure postcranial elements reflects interelemental variability. Further research involving additional needed explore other palaeobiological aspects , such dynamics, sexual dimorphisms, locomotion, among others.

Language: Английский

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Palaeobiological inferences of the aetosaur Aetosauroides scagliai (Archosauria: Pseudosuchia) based on microstructural analyses of its appendicular bones

Historical Biology, Journal Year: 2022, Volume and Issue: 35(3), P. 303 - 314

Published: Feb. 26, 2022

Aetosaurs were a group of armoured pseudosuchians, recorded in most the Upper Triassic continental deposits worldwide. Several osteohistological contributions aetosaurs focused on their osteoderms, but rarely appendicular bones. Here, we analyse microstructure humerus, femur and tibia Aetosauroides scagliai (specimens PVL 2073 [holotype] 2052). These exhibit cortical bone formed by highly vascularised fibrolamellar present inner portion cortex, mixed with scarce parallel-fibred bone. Also, they show outermost cortex. A general growth pattern that includes first rapid stage followed slow is reported. Nevertheless, rate presence embedded layers recognise more variation within Aetosauria. The value bones osteoderms as age estimators variable, being useful early stages, late stages are better (based particular osteoderms). Through morphological (neurocentral sutures) histological (EFS absent) information, holotype (PVL 2073) was recovered between juvenile subadult stages. Using statistical model combines microanatomical data, terrestrial lifestyle inferred for Aetosauroides, which concur previous analyses.

Language: Английский

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Life history and growth dynamics of a peirosaurid crocodylomorph (Mesoeucrocodylia; Notosuchia) from the Late Cretaceous of Argentina inferred from its bone histology

Journal of Anatomy, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 23, 2025

Abstract Notosuchia were a successful lineage of Crocodyliformes that achieved remarkable diversity during the Cretaceous Gondwana, particularly in South America. Although paleohistology has expanded our knowledge paleobiology notosuchians, several clades this remain poorly understood aspect. Here we help to address gap by conducting first histological analysis appendicular bones peirosaurid. To increase about growth dynamics and examine intraeskeletal interspecific variation, analyze microstructure tibia, fibula, phalanx, fragment ornamented element (possible osteoderm or skull bone) possible long bone an individual assigned Peirosauridae indet. (MAU‐Pv‐437). The peirosaurid studied here appears have reached sexual but not somatic maturity minimum age inferred from results lower estimated than osteoderms previous study on same individual. cortical MAU‐Pv 437 is formed vascularized parallel fibered bone/lamellar which indicates experienced moderate rate. This different what been observed for other notosuchians specimens, suggesting lack uniform pattern clade.

Language: Английский

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Osteohistology of a Triassic dinosaur population reveals highly variable growth trajectories typified early dinosaur ontogeny

Scientific Reports, Journal Year: 2022, Volume and Issue: 12(1)

Published: Oct. 15, 2022

Abstract Intraspecific variation in growth trajectories provides a fundamental source of upon which natural selection acts. Recent work hints that early dinosaurs possessed elevated levels such compared to other archosaurs, but comprehensive data uniting body size, bone histology, and morphological from stratigraphically constrained dinosaur population are needed test this hypothesis. The Triassic theropod Coelophysis bauri , known bonebed preserving single coeval individuals, an exceptional system assess whether highly variable patterns were present near the origin Dinosauria. Twenty-four histologically sampled individuals less than year at least four years old confirm right-skewed age distribution assemblage. Poor correlations among age, maturity strongly support presence unique, relative archosaurs their living kin.

Language: Английский

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Palaeobiological inferences of “rauisuchians” Fasolasuchus tenax (Los Colorados Fm., Argentina) and Prestosuchus chiniquensis (Santa Maria Super sequence, Brazil) from the Middle–Upper Triassic of South America based on microstructural analyses

Journal of Anatomy, Journal Year: 2023, Volume and Issue: 243(6), P. 893 - 909

Published: July 31, 2023

"Rauisuchia" is a non-monophyletic group of quadrupedal and carnivorous pseudosuchians that inhabited the entire world during Middle-Upper Triassic period (Anisian/Ladinian-Rhaetian). In South America, "rauisuchians" reached largest sizes among continental carnivores. Despite their important ecological role, some aspects palaeobiology have been poorly examined. Here, we study appendicular bones, dorsal ribs osteoderms two genera, Argentinean Fasolasuchus tenax (PVL 3850, holotype) Brazilian Prestosuchus chiniquensis (SNSB-BSPG AS XXV) respectively. The femur F. formed by laminar fibrolamellar bone, which composed non-fully monorefringent woven-fibred matrix primary osteons; rib has Haversian bone composition with an external fundamental system recorded osteoderm well-organised parallel-fibred bone. femur, humerus fibula P. are mostly strongly arranged vascularisation. minimal ages obtained correspond to 9 years for (based on maximum number growth marks in osteoderm) 4 (obtained from highest count humerus). attained somatic skeletal maturity, while was near reaching sexual but it somatically immature. overall rapid rate high uniform vascularisation seems imply these features common most "rauisuchians", except chiniquensis.

Language: Английский

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Fossil bone histology reveals ancient origins for rapid juvenile growth in tetrapods

Communications Biology, Journal Year: 2022, Volume and Issue: 5(1)

Published: Nov. 28, 2022

Patterns of growth throughout the lifetime an animal reflect critical life history traits such as reproductive timing, physiology, and ecological interactions. The ancestral pattern for tetrapods has traditionally been described slow-to-moderately paced, akin to modern amphibians, with fast high metabolic rates considered a specialized physiological trait amniotes. Here, we present bone histology from ontogenetic series Early Carboniferous stem tetrapod Whatcheeria deltae, document evidence fibrolamellar bone-primary tissue associated growth. Our data indicate that juveniles grew rapidly reached skeletal maturity quickly, allowing them occupy large-bodied predator niche in their paleoenvironment. This strategy contrasts those other indicates diversity patterns existed at origins diversification. Importantly, marks unexpectedly early occurrence Tetrapoda, both temporally phylogenetically. These findings reveal elevated juvenile is not limited amniotes, but deep clade may have played previously unrecognized role invasion land.

Language: Английский

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Comptonatus chasei , a new iguanodontian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, southern England

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

Published: July 9, 2024

A new iguanodontian dinosaur, Comptonatus chasei gen. et sp. nov., is described from the Lower Cretaceous Wessex Formation of Isle Wight. These strata provide an important record a critical time in development diversity. The specimen, which here for first time, was found and excavated 2013 represents most complete skeleton discovered Wealden Group century. taxon diagnosed by several autapomorphies neurocranium, teeth, coracoid other parts body, together with unique suite characters. include dentary straight ventral border, markedly expanded prepubic blade. features set it apart sympatric Mantellisaurus atherfieldensis, Brighstoneus simmondsi Iguanodon cf. bernissartensis, increasing known diversity this clade Barremian–early Aptian England. http://zoobank.org/urn:lsid:zoobank.org:pub:2F3125A5-BDEF-4835-8829-92104752A86F

Language: Английский

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Inferring longevity from advanced rib remodelling in insular dwarf deer

Biological Journal of the Linnean Society, Journal Year: 2022, Volume and Issue: 136(1), P. 41 - 58

Published: Feb. 15, 2022

Abstract Dwarfed insular mammals are of significant interest to evolutionary biology because their morphological and physiological adaptations triggered by variables inherent geographical isolation. One life history trait that is expected be modified in relation body size reduction extended longevity facilitated ecological parameters such as predator competitor release fluctuating resource availability. However, systematic examination extreme cases dwarfism difficult largely represented fossils extinct species. We studied seven rib fragments the extraordinary endemic Pleistocene dwarf deer Candiacervus (size 2) test whether its bone matrix shows evidence for extensive remodelling typically seen large long-living mammals. found all ribs had well-remodelled Haversian bone, implying several generations resorption re-deposition processes. Osteon density was high relative small cross-section size, with examples porosity similar elderly animals. report first combined micro-morphological micro-morphometric record histology, agreeing previous literature discussing ruminants. Further experimental validation osteon extant will confirm dwarfed indeed lived longer than mass.

Language: Английский

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Incongruent ontogenetic maturity indicators in a Late Triassic archosaur (Aetosauria: Typothorax coccinarum)

The Anatomical Record, Journal Year: 2023, Volume and Issue: 307(4), P. 1254 - 1270

Published: Nov. 8, 2023

Abstract Maximum individual body size in pseudosuchian archosaurs is not well constrained the fossil record, but it may be influenced by a variety of factors including basal metabolic rate, evolutionary relationships, and environmental conditions. Body varies among Aetosauria which estimated total length ranges between 1 m (e.g., Coahomasuchus kahleorum ) 5 Desmatosuchus spurensis ). A new, very large specimen aetosaurian Typothorax coccinarum from Petrified Forest National Park northeastern Arizona nearly twice all other known specimens largest aetosaur currently worldwide. The lacks co‐ossified neurocentral sutures trunk vertebrae suggest that had yet reached skeletal maturity, smaller T. exhibit partially or fully same region. If correlates with maturity aetosaurs, this discrepancy warns timing suture co‐ossification aetosaurs reliable indicator ontogenetic stage. Osteohistological observations rib demonstrate although PEFO 42506 shows size, did deposit an external fundamental system despite depositing as many 19 growth lines, further indicating maturity. Thus, at least within Aetosauria, correlate, whereas can incongruent comparison. Furthermore, indicates non‐desmatosuchin could sizes suggests some have experienced indeterminate growth.

Language: Английский

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