A quantitative test of the “Ecomorphotype Hypothesis” for fossil true seals (Family Phocidae) DOI Creative Commons
James Rule, Gustavo Burin, Travis Park

et al.

PeerJ, Journal Year: 2024, Volume and Issue: 12, P. e17592 - e17592

Published: June 19, 2024

The fossil record of true seals (Family Phocidae) is mostly made up isolated bones, some which are type specimens. Previous studies have sought to increase referral non-overlapping and unrelated fossils these taxa using the 'Ecomorphotype Hypothesis', stipulates that certain differences in morphology between represent adaptations differing ecology. On this basis, bulk material could be lumped a specific ecomorphotype, then referred species even if they different bones. This qualitative subjective method has been used often expand taxonomy phocids, but never quantitatively tested. We test proposed ecomorphotypes morphometric analysis extant northern seal limb specifically principal components discriminant function analysis. A large amount morphological overlap ecomorphotypes, poor discrimination them, suggests Hypothesis' not valid approach. Further, failed assign designated previous studies, with from same being as ecomorphotypes. failure approach all should considered unknown taxonomic status. In light this, findings phocid bones limited utility specimens, we revise status named species. conclude majority nomina dubia.

Language: Английский

Morphology and function of pinniped necks: The long and short of it DOI Creative Commons

J. Keller,

Annalisa Berta,

Mark S. Juhn

et al.

The Anatomical Record, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 21, 2025

Abstract Terrestrial vertebrates from at least 30 distinct lineages in both extinct and extant clades have returned to aquatic environments. With these transitions came numerous morphological adaptations accommodate life water. Relatively little attention has been paid the cervical region when tracking this transition. In fully cetaceans, vertebrae are compressed, largely because a loss of neck mobility reduces drag. We ask whether pattern evolution is present more recently evolved semiaquatic pinnipeds. Here, we compare morphology function three families pinnipeds, Otariidae, Phocidae, Odobenidae as well between pinnipeds their terrestrial arctoid relatives (ursids mustelids). Using cranial CT scans, quantified occipital surface area for muscle attachment vertebral size shape using linear measurements. Results show that relatively larger than ursids mustelids, suggesting marine carnivorans enlarged muscles assist with head stabilization during swimming. Within found quantitative differences otariids phocids coincide locomotor style. Phocids hindlimb‐dominated swimmers propel themselves pelvic oscillations. Their necks stiff compressed anteroposteriorly reduced muscular areas. By contrast, forelimb‐dominated locomote water on land pectoral limbs, often recruiting initiate turns underwater assisting “walking” land. Consequently, stronger, flexible phocids, which reflected elongate centra attachments. The walrus (Odobenidae) intermediate otariids, consistent phocid swimming mode combined likely functions intraspecific conflict haul‐out behavior.

Language: Английский

Citations

1
Bioluminescence and repeated deep-sea colonization shaped the diversification and body size evolution of squaliform sharks DOI
A. Marion, Fabien L. Condamine, Guillaume Guinot

et al.

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2025, Volume and Issue: 292(2042)

Published: March 1, 2025

Understanding the underlying mechanisms that have generated striking biodiversity inhabiting deep-sea ecosystems remains a challenge in evolutionary biology. Here, we addressed this topic by studying macroevolutionary dynamics shaped diversification of squaliform sharks, an iconic clade vertebrates. Using phylogenetic comparative methods and fossil-based Bayesian estimates, both at species level, combined fossil record data with molecular phylogenies to provide quantitative framework for understanding history Squaliformes. We reveal early lineages originated shallow water during Early Cretaceous experienced multiple independent shifts toward deep sea Late Cretaceous. Importantly, show these were likely facilitated acquisition bioluminescence, which significantly impacted body size evolution among lineages. Furthermore, colonization events coincide periods climate warming marine transgression Cenomanian-Turonian Palaeocene-Eocene transitions. Following colonizations, diversified over last 30 Myr, resulting one richest radiations sharks. These results demonstrate how complex interplay between key innovation new habitats drove major ecological transition, highlighting importance integrative when deep-time dynamics.

Language: Английский

Citations

1
The Miocene seal Monachopsis pontica : isolated in a shrinking sea and adapting to its changing conditions DOI Creative Commons
Pavlo Otriazhyi, Davit Vasilyan, Karina Vishnyakova

et al.

Royal Society Open Science, Journal Year: 2025, Volume and Issue: 12(3)

Published: March 1, 2025

More than 170 years have passed since the description of dwarf Miocene seal Monachopsis pontica. However, its cranial materials were rarely found and described. This paper re-describes M. pontica discusses ecological adaptations. is among latest seals that survived in epicontinental sea Eastern Paratethys during Khersonian biotic crisis. Newly examined from Ukraine, being exceptional their completeness, show previously unknown traits morphology, unique subfamily Phocinae. distinguished by small body size (85-105 cm long), long snout deltoid crest humerus. Dental morphology shows was using raptorial methods catching prey. pattern tooth wear also indicates suction feeding. The unusually could be interpreted as a result decreasing basin absence predators. High crests on limb bones evidence development musculature driven pachyosclerosis skeleton. Phylogenetic analysis placed at base crown Phocinae, crownward to most known seals.

Language: Английский

Citations

0
Postweaning horizontal movements and diving behavior of a recovering grey seal (Halichoerus grypus atlantica) population in the western North Atlantic DOI Creative Commons
Eleanor I. Heywood,

Kimberly T. Murray,

Lynda Doughty

et al.

Animal Biotelemetry, Journal Year: 2025, Volume and Issue: 13(1)

Published: March 29, 2025

Language: Английский

Citations

0
A quantitative test of the “Ecomorphotype Hypothesis” for fossil true seals (Family Phocidae) DOI Creative Commons
James Rule, Gustavo Burin, Travis Park

et al.

PeerJ, Journal Year: 2024, Volume and Issue: 12, P. e17592 - e17592

Published: June 19, 2024

The fossil record of true seals (Family Phocidae) is mostly made up isolated bones, some which are type specimens. Previous studies have sought to increase referral non-overlapping and unrelated fossils these taxa using the 'Ecomorphotype Hypothesis', stipulates that certain differences in morphology between represent adaptations differing ecology. On this basis, bulk material could be lumped a specific ecomorphotype, then referred species even if they different bones. This qualitative subjective method has been used often expand taxonomy phocids, but never quantitatively tested. We test proposed ecomorphotypes morphometric analysis extant northern seal limb specifically principal components discriminant function analysis. A large amount morphological overlap ecomorphotypes, poor discrimination them, suggests Hypothesis' not valid approach. Further, failed assign designated previous studies, with from same being as ecomorphotypes. failure approach all should considered unknown taxonomic status. In light this, findings phocid bones limited utility specimens, we revise status named species. conclude majority nomina dubia.

Language: Английский

Citations

1