Reassessment of the possible size, form, weight, cruising speed, and growth parameters of the extinct megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), and new evolutionary insights into its gigantism, life history strategies, ecology, and extinction

Palaeontologia Electronica, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Otodus megalodon (Lamniformes: Otodontidae) is an iconic Neogene shark, but the lack of well-preserved skeletons has hampered our understanding various aspects its biology. Here, we reassess some biological properties using a new approach, based on known vertebral specimens O. and 165 species extinct extant neoselachian sharks across ten orders. Using median neurocranial caudal fin proportions relative to trunk proportion among non-mitsukurinid/non-alopiid lamniforms, show that could have had slender body possibly reached about 24.3 m in length. Allometric considerations indicate stout plan like white shark (Carcharodon carcharias) for incurred excessive hydrodynamic costs, further supporting interpretation likely slenderer than C. carcharias. A 24.3-m-long may weighed around 94 t, with estimated cruising speed 2.1-3.5 km h-1. reanalysis growth bands suggests size at birth 3.6-3.9 megalodon, previous interpretations ovoviviparity embryos' intrauterine oophagous behavior, less need nursery areas. Additional inferred patterns corroborated by fossil record support hypothesis emergence carcharias during Early Pliocene least partly responsible demise due competition resources. These are working hypotheses expected serve as reasonable reference points future studies biology megalodon.

Language: Английский

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Dental and mandibular morphology of Peligrotherium tropicalis (Mammalia, Meridiolestida) from the Paleocene of Patagonia, Argentina

Journal of Mammalian Evolution, Journal Year: 2025, Volume and Issue: 32(2)

Published: April 29, 2025

Language: Английский

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Shell Constraints on Evolutionary Body Size–Limb Size Allometry Can Explain Morphological Conservatism in the Turtle Body Plan

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(11)

Published: Nov. 1, 2024

Turtles are a small clade of vertebrates despite having existed since the Late Triassic. have conservative body plan relative to other amniotes, characterized by presence shell and quadrupedality. This morphology is even retained in strong ecological specialists, such as sea turtles, which secondarily adapted marine locomotion allometric scaling their hands. It possible that turtles strongly influenced shell, acting constraint achieving greater diversity forms. Here, we explore evolutionary relationships fore- hindlimb stylopodia (i.e., humerus femur) with one another well relationship size (carapace length) assess evidence constraint. All including Triassic shelled stem near-isometric do not vary between clades, evolve at slow rates. indeed indicates proportions constrained narrow range possibilities. Minor deviations seen highly aquatic softshell modified shells bone losses. Our regressions allow accurate estimations for fossils. Several independent turtle lineages converged on maximum sizes 2.2 m length, may be biological group.

Language: Английский

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Ontogenetic scaling of disc width with total length in west African batoids

Evolutionary Ecology, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 11, 2024

Abstract Morphological scaling describes changes in the size or shape of one morphological character (e.g. mass, length, width, area etc.) as another increases size. Understanding how characters scale with body can shed light on natural selection influences morphology, and nature ecomorphological relationships through ontogeny. Batoids (Elasmobranchii: Batoidea) are a highly specialised lineage cartilaginous fishes displaying extreme dorsoventral flattening. Despite this, little is known about batoids compared to sharks. In this study we test relationship between disc width total length five batoid species ( Torpedo torpedo , Mobula tarapacana Fontitrygon margarita Raja parva Rhinobatos irvinei) representing four orders that differ both ecology measured from artisanal fisheries Western Central Ghana. Whilst lack existing ecological data presents some limitations, our results broadly consistent theory previously applied Moreover, find for lineages (including myliobatiform taxa) may represent valid proxy estimating overall This finding has applications estimation partially processed obtained fishing camps, extinct taxa only incomplete fragmented remains.

Language: Английский

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Body mass estimation from cheek tooth measurements in extinct caviomorphs (Ctenohystrica, Hystricognathi): the importance of predictor, reference sample and method

Journal of Mammalian Evolution, Journal Year: 2024, Volume and Issue: 31(4)

Published: Dec. 1, 2024

Language: Английский

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