How to weigh a fossil mammal? South American notoungulates as a case study for estimating body mass in extinct clades

Journal of Mammalian Evolution, Journal Year: 2023, Volume and Issue: 30(3), P. 773 - 809

Published: July 12, 2023

Language: Английский

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Downsizing a heavyweight: factors and methods that revise weight estimates of the giant fossil whale Perucetus colossus

PeerJ, Journal Year: 2024, Volume and Issue: 12, P. e16978 - e16978

Published: Feb. 29, 2024

Extremes in organismal size have broad interest ecology and evolution because dictates many traits of an organism’s biology. There is particular fascination with identifying upper extremes the largest vertebrates, given challenges difficulties measuring extant extinct candidates for animal all time, such as whales, terrestrial non-avian dinosaurs, marine reptiles. The discovery Perucetus colossus , a giant basilosaurid whale from Eocene Peru, challenged assumptions about based on reconstructions its body weight that exceeded reported values blue whales ( Balaenoptera musculus ). Here we present examination series factors methodological approaches to assess reconstructing including: data sources large cetaceans; fitting published mass estimates outlines; testing assumption isometry between skeletal masses, even extrapolation; examining role pachyostosis reconstructions; addressing method-dependent error rates; comparing known physiological ecological limits living oceanic productivity. We conclude did not exceed today’s whales. Depending methods, estimate weighed 60–70 tons assuming length 17 m. calculated larger potentially much 98–114 at 20 m length, which far less than direct records weights, or 270 ton weights measured by length.

Language: Английский

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A test of the lateral semicircular canal correlation to head posture, diet and other biological traits in “ungulate” mammals

Scientific Reports, Journal Year: 2020, Volume and Issue: 10(1)

Published: Nov. 11, 2020

Abstract For over a century, researchers have assumed that the plane of lateral semicircular canal inner ear lies parallel to horizon when head is at rest, and used this assumption reconstruct posture in extinct species. Although hypothesis has been repeatedly questioned, it never tested on large sample size broad taxonomic scale mammals. This study presents comprehensive test one hundred “ungulate” Using CT scanning manual segmentation, orientation skull was reconstructed as if bony labyrinth aligned horizontally. cranial statistically compared actual corresponding species using dataset 10,000 photographs phylogenetic regression analysis. A significant correlation between found, although departs significantly from horizontal. We thus caution against use proxy infer precisely horizontal dry skulls Diet (browsing or grazing) head-butting behaviour are correlated canal, but not posture. Head both strongly with history.

Language: Английский

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Femoral specializations to locomotor habits in early archosauriforms

Journal of Anatomy, Journal Year: 2021, Volume and Issue: 240(5), P. 867 - 892

Published: Nov. 28, 2021

Abstract The evolutionary history of archosaurs and their closest relatives is characterized by a wide diversity locomotor modes, which has even been suggested as pivotal aspect underlying the success dinosaurs vs. pseudosuchians across Triassic–Jurassic transition. This (e.g., more sprawling/erect; crouched/upright; quadrupedal/bipedal) led to several morphofunctional specializations archosauriform limb bones that have studied qualitatively well quantitatively through various linear morphometric studies. However, differences in habits never transition using 3D geometric morphometrics, can relate how morphological features vary according biological factors such habit body mass. Herein, we investigate variation dataset 72 femora from 36 different species archosauriforms. First, identify femoral head rotation, distal slope fourth trochanter, curvature, angle between lateral condyle crista tibiofibularis main varying bipedal quadrupedal taxa, all these traits having stronger signal than lesser trochanter's proximal extent. We show significant association mode phylogeny, but with being phylogenetic signal. enables us predict modes some ambiguous early archosauriforms without relying on relationships hindlimb forelimb bone dimensions prior Second, highlight most important linked increase size, impacts width epiphyses roundness proximodistal position trochanter. Furthermore, allometric trajectories along relation size. Finally, demonstrate covariation variations bowing (anteroposterior curvature) distinct among robust gracile ones. also decoupling trochanter (symmetrical semi‐pendant) size (sharp rounded). Our results indicate similar level disparity clear convergence robusticity two clades (Pseudosuchia Avemetatarsalia), emphasizing importance accounting for when studying history, functional morphology appendicular features. Determining skeletal were impacted discuss potential homoplasy characters used previously cladistic analyses bipedalism evolved avemetatarsalian lineage. study illuminates evolution was functionally constrained should aid ongoing discussions about nature “success” over pseudosuchians.

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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Absolute abundance and preservation rate of Tyrannosaurus rex

Science, Journal Year: 2021, Volume and Issue: 372(6539), P. 284 - 287

Published: April 15, 2021

Estimating dinosaur abundance the of a species is common practice for extant and can reveal many aspects its ecology, evolution, threat level. that are extinct, especially those long much trickier endeavor. Marshall et al. used relationship established between body size population density in to estimate traits such as density, distribution, total biomass, persistence one best-known dinosaurs, Tyrannosaurus rex , revealing previously hidden ecology. Science this issue p. 284

Language: Английский

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Walking—and Running and Jumping—with Dinosaurs and their Cousins, Viewed Through the Lens of Evolutionary Biomechanics

Integrative and Comparative Biology, Journal Year: 2022, Volume and Issue: 62(5), P. 1281 - 1305

Published: May 20, 2022

Abstract Archosauria diversified throughout the Triassic Period before experiencing two mass extinctions near its end ∼201 Mya, leaving only crocodile-lineage (Crocodylomorpha) and bird-lineage (Dinosauria) as survivors; along with pterosaurian flying reptiles. About 50 years ago, “locomotor superiority hypothesis” (LSH) proposed that dinosaurs ultimately dominated by Early Jurassic because their locomotion was superior to other archosaurs’. This idea has been debated continuously since, taxonomic morphological analyses suggesting were “lucky” rather than surviving due being biologically superior. However, LSH never tested biomechanically. Here we present integration of experimental data from in extant archosaurs inverse predictive simulations same behaviours using musculoskeletal models, showing can reliably predict how walk, run jump. These have guiding extinct estimate they moved, show our progress endeavour. The models used these also be for simpler form function such muscle moment arms, which inform us about more basic biomechanical similarities differences between archosaurs. Placing all into an evolutionary context, take a fresh look at part critical review competing hypotheses why (and few archosaur clades) survived Late extinctions. had some quantifiable locomotor performance vs. archosaurs, but derived dinosaurian features (e.g., metabolic or growth rates, ventilatory abilities) are not necessarily mutually exclusive LSH; maybe even opportunistic replacement hypothesis; explaining dinosaurs’ success.

Language: Английский

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An Italian dinosaur Lagerstätte reveals the tempo and mode of hadrosauriform body size evolution

Scientific Reports, Journal Year: 2021, Volume and Issue: 11(1)

Published: Dec. 2, 2021

Abstract During the latest Cretaceous, European Archipelago was characterized by highly fragmented landmasses hosting putative dwarfed, insular dinosaurs, claimed as fossil evidence of “island rule”. The Villaggio del Pescatore quarry (north-eastern Italy) stands most informative locality within palaeo-Mediterranean region and represents first, multi-individual Konservat-Lagerstätte type dinosaur-bearing in Italy. site is here critically re-evaluated early Campanian age, thus preceding final fragmentation stages Archipelago, including all other localities preserving hypothesized dwarfed taxa. New skeletal remains allowed osteohistological analyses on hadrosauroid Tethyshadros insularis indicating subadult features specimen whereas a second, herein newly described, larger individual likely somatically mature. A phylogenetic comparative framework places body-size T. range with non-hadrosaurid Eurasian hadrosauroids, rejecting any significant evolutionary trend towards miniaturisation this clade, confuting its ‘pygmy’ status, providing unmatched data to infer environmentally-driven trends Mesozoic dinosaurs.

Language: Английский

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How smart wasT. rex? Testing claims of exceptional cognition in dinosaurs and the application of neuron count estimates in palaeontological research

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 12, 2024

Recent years have seen increasing scientific interest in whether neuron counts can act as correlates of diverse biological phenomena. Lately, Herculano-Houzel (2023) argued that fossil endocasts and comparative neurological data from extant sauropsids allow to reconstruct telencephalic Mesozoic dinosaurs pterosaurs, which might proxies for behaviors life history traits these animals. According this analysis, large theropods such Tyrannosaurus rex were long-lived, exceptionally intelligent animals equipped with 'macaque- or baboon-like cognition' whereas sauropods well most ornithischian would displayed significantly smaller brains an ectothermic physiology. Besides challenging established views on dinosaur biology, claims raise questions count estimates could benefit research general. Here, we address findings by revisiting Herculano-Houzel's work, identifying several crucial shortcomings regarding analysis interpretation. We present revised encephalization dinosaurs, derive phylogenetically informed modeling amended dataset endocranial measurements. For large-bodied particular, recover lower than previously proposed. Furthermore, review the suitability variables numbers relative brain size predict cognitive complexity, metabolic rate coming conclusion they are flawed Instead relying when reconstructing argue integrative studies needed approach complex subject.

Language: Английский

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High‐precision body mass predictors for small mammals: a case study in the Mesozoic

Palaeontology, Journal Year: 2024, Volume and Issue: 67(2)

Published: March 1, 2024

Abstract Body mass is a pivotal quantity in palaeobiology but must be inferred from an imperfect fossil record. We analyse the performance of regression models derived various dentoskeletal predictors mammals to inform fossils early, Mesozoic history this radiation. Our focus on critical small end size spectrum; because earliest were small, persisted onto stems major extant radiations, and compose large proportion crown diversity. The sampling strategy diverse terms both phylogeny skeletal predictors: former allows general application, while latter enables comparison models. Linear regressions based indicate universal correlation body with observed measurements, clear differences precision. Postcranial outperform jaw dental metrics, certain femoral joint dimensions providing surprisingly precise predictions. results complex patterns evolution within small‐bodied category, including possibility that multiple species approached theoretical lower limit mammalian size. ability study such dynamics only becomes possible when predicting strict, highly focused phylogenetic context. heuristic value we provide here not limited applicable any geologic age.

Language: Английский

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