New seal mandibles belonging to the subfamilies Monachinae and Phocinae discovered in the Neogene of North Carolina (USA)

Hafed, Azizah B.; Nance, John R.; Koretsky, Irina A.; Rahmat, Sulman

doi:10.1080/08912963.2022.2063053

Cited by 2 publications

(1 citation statement)

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“…This technique, which relies on subjective qualitative morphological coding, has been used to refer a multitude of fossils to species ( e.g., Praepusa vindobonensis , Phocanella pumila , Leptophoca proxima ) with otherwise isolated postcranial type specimens ( Koretsky & Grigorescu, 2002 ; Koretsky, 2003 ; Koretsky & Peters, 2008 ; Koretsky & Ray, 2008 ; Koretsky, Ray & Peters, 2012 ; Koretsky & Rahmat, 2013 ; Koretsky, Rahmat & Peters, 2014 ; Koretsky, Peters & Rahmat, 2015 ; Rahmat & Koretsky, 2016 ; Rahmat et al, 2017 ; Rahmat & Koretsky, 2018 ; Hafed et al, 2023 ). This occasionally includes fossils other than the mandible, humerus, and femur, or fossil elements that are fragmentary and incomplete.…”

Section: Introductionmentioning

confidence: 99%

A quantitative test of the “Ecomorphotype Hypothesis” for fossil true seals (Family Phocidae)

Rule,

Burin,

Park

2024

PeerJ

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

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