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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Theropod guild structure and the tyrannosaurid niche assimilation hypothesis: implications for predatory dinosaur macroecology and ontogeny in later Late Cretaceous Asiamerica¹

Canadian Journal of Earth Sciences, Journal Year: 2021, Volume and Issue: 58(9), P. 778 - 795

Published: June 17, 2021

Well-sampled dinosaur communities from the Jurassic through early Late Cretaceous show greater taxonomic diversity among larger (>50 kg) theropod taxa than of Campano-Maastrichtian, particularly to those eastern/central Asia and Laramidia. The large carnivore guilds in Asiamerican assemblages are monopolized by tyrannosaurids, with adult medium-sized (50–500 predators rare or absent. In contrast, various clades theropods found occupy these body sizes earlier faunas, including tyrannosauroids. Assemblages “missing middle-sized” not have correspondingly sparser potential prey species recorded same faunas. niches Laramidia may been assimilated juvenile subadults tyrannosaurid species, functionally distinct their ecomorphologies. It is speculated that if tyrannosaurids previously occupied mid-sized predators, we would expect evolution transitions morphology possibly delay achievement somatic maturity this taxon.

Language: Английский

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Macroevolutionary trends in theropod dinosaur feeding mechanics

Current Biology, Journal Year: 2021, Volume and Issue: 32(3), P. 677 - 686.e3

Published: Dec. 16, 2021

Language: Английский

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

Lethaia, Journal Year: 2025, Volume and Issue: 58(1), P. 1 - 12

Published: Feb. 20, 2025

Language: Английский

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3D Focused Ion Beam Microscopy of FossilizedAlbertosaurus sarcophagusreveals Nano to Microscale Structures

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: April 19, 2025

ABSTRACT Osteohistological investigations of fossilized bone can reveal details about the specimen’s biological, geological and environmental conditions. Micro-to-nanoscale imaging provides insight into structural organization also indicators fossilization process. We examined a petrographic thin section left fibula ∼71.5 million-year-old Albertosaurus sarcophagus (Canadian Museum Nature [CMN] catalogue number FV 11315) using nanoscale scanning electron microscopy (SEM) focused ion beam (FIB)-SEM tomographic to study arrangement mineral organic components fossil in multidimensions. Here, we present evidence permineralization Haversian canals by energy dispersive X-ray spectroscopy. Nanoscale 3D FIB-SEM revealed that characteristic 67 nm banding periodicity collagen fibrils was remarkably well preserved over 70M years, allowed for detection fibril bundles parallel fibered lamellar arrangements. A newly discovered structure modern bone, ellipsoidal cluster, tiled throughout space fibrolamellar bone. These observations, afforded high-resolution site-specific nature FIB-SEM, link key features with micro-nanoscale modern-day This investigation highlights persistence formation persisting millions years.

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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Mammal‐bearing gastric pellets potentially attributable to Troodonformosus at the Cretaceous Egg Mountain locality, Two Medicine Formation, Montana, USA

Palaeontology, Journal Year: 2021, Volume and Issue: 64(5), P. 699 - 725

Published: July 28, 2021

Abstract Fossil gastric pellets (regurgitalites) have distinct taphonomic characteristics that facilitate inferences of behavioural ecology in deep time, despite their rarity the fossil record. Using patterns both extant and small mammals from more recent geologic deposits as a guide, we assess taphonomy three unusual multi‐individual aggregates mammal skeletons palaeosols at Egg Mountain, dinosaur nesting locality Upper Cretaceous Two Medicine Formation, Montana, USA. One aggregate consists two individuals multituberculate Filikomys primaevus . This specimen is characterized by brecciated crania, articulated postcrania, an absence digestive markings, all suggestive non‐predatory origin. additional consist 3 11 individuals, respectively, primarily marsupialiform Alphadon halleyi High proportions crania indigestible elements (e.g. teeth), extensive disarticulation breakage, corrosion patterns, phosphatic ground mass are indicative regurgitalites align with features prey diurnal raptor pellets. We interpret these specimens oldest known mammal‐bearing regurgitalites. The discrepancy implies separation between mammalian taxa locality. Abundant shed teeth evidence favours non‐avian theropod Troodon formosus predator responsible for regurgitalites, congruent previous small‐bodied diet, manipulation during feeding, heightened metabolic processes, potential nocturnality this taxon.

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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Generalist diet of Microraptor zhaoianus included mammals

Journal of Vertebrate Paleontology, Journal Year: 2022, Volume and Issue: 42(2)

Published: Aug. 31, 2022

Gut contents are extremely important for inferring trophic interactions between extinct species. These are, however, very rare in the fossil record and it is not always possible to accurately identify both carnivore consumed organisms. Here we describe remains of a small mammal foot preserved inside body cavity holotype specimen feathered dinosaur Microraptor zhaoianus. This adds known diversity diet this genus, which also birds, fish, lizards. Previous interpretations that was an arboreal hunter birds adept fish supported. Although various stomach would be plausible prey items based on size, there no clear evidence any them were predated rather than scavenged, likely did foraged multiple habitats.

Language: Английский

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