Species delimitation and coexistence in an ancient, depauperate vertebrate clade

Abstract Background A major challenge to understanding how biodiversity has changed over time comes from depauperons, which are long-lived lineages with presently low species diversity. The most famous of these are the coelacanths. This clade of lobe-finned fishes occupies a pivotal position on the...

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Main Authors: Chase Doran Brownstein, Immanuel Chas Bissell
Format: Article
Language:English
Published: BMC 2022-07-01
Series:BMC Ecology and Evolution
Subjects:
Online Access:https://doi.org/10.1186/s12862-022-02043-4
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author Chase Doran Brownstein
Immanuel Chas Bissell
author_facet Chase Doran Brownstein
Immanuel Chas Bissell
author_sort Chase Doran Brownstein
collection DOAJ
description Abstract Background A major challenge to understanding how biodiversity has changed over time comes from depauperons, which are long-lived lineages with presently low species diversity. The most famous of these are the coelacanths. This clade of lobe-finned fishes occupies a pivotal position on the vertebrate tree between other fishes and tetrapods. Yet only two extant species and fewer than 100 extinct forms are known from the coelacanth fossil record, which spans over 400 million years of time. Although there is evidence for the existence of additional genetically isolated extant populations, a poor understanding of morphological disparity in this clade has made quantifying coelacanth species richness difficult. Results Here, we quantify variation in a sample of skulls and skeletons of the Triassic eastern North American coelacanth †Diplurus that represents the largest assemblage of coelacanth individuals known. Based on the results of these quantitative comparisons, we identify a diminutive new species and show that multiple lacustrine ecosystems in the Triassic rift lakes of the Atlantic coastline harbored at least three species of coelacanths spanning two orders of magnitude in size. Conclusions Conceptions about the distribution of species diversity on the tree of life may be fundamentally misguided when extant diversity is used to gauge signals of extinct diversity. Our results demonstrate how specimen-based assessments can be used to illuminate hidden biodiversity and show the utility of the fossil record for answering questions about the hidden richness of currently species-poor lineages.
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spelling doaj.art-7ccd773482054ad3803107f008f8ba9f2022-12-22T03:01:10ZengBMCBMC Ecology and Evolution2730-71822022-07-0122111510.1186/s12862-022-02043-4Species delimitation and coexistence in an ancient, depauperate vertebrate cladeChase Doran Brownstein0Immanuel Chas Bissell1Stamford Museum and Nature CenterDepartment of Earth and Planetary Sciences, Yale UniversityAbstract Background A major challenge to understanding how biodiversity has changed over time comes from depauperons, which are long-lived lineages with presently low species diversity. The most famous of these are the coelacanths. This clade of lobe-finned fishes occupies a pivotal position on the vertebrate tree between other fishes and tetrapods. Yet only two extant species and fewer than 100 extinct forms are known from the coelacanth fossil record, which spans over 400 million years of time. Although there is evidence for the existence of additional genetically isolated extant populations, a poor understanding of morphological disparity in this clade has made quantifying coelacanth species richness difficult. Results Here, we quantify variation in a sample of skulls and skeletons of the Triassic eastern North American coelacanth †Diplurus that represents the largest assemblage of coelacanth individuals known. Based on the results of these quantitative comparisons, we identify a diminutive new species and show that multiple lacustrine ecosystems in the Triassic rift lakes of the Atlantic coastline harbored at least three species of coelacanths spanning two orders of magnitude in size. Conclusions Conceptions about the distribution of species diversity on the tree of life may be fundamentally misguided when extant diversity is used to gauge signals of extinct diversity. Our results demonstrate how specimen-based assessments can be used to illuminate hidden biodiversity and show the utility of the fossil record for answering questions about the hidden richness of currently species-poor lineages.https://doi.org/10.1186/s12862-022-02043-4CoelacanthsDiversitySpeciationPaleontologyTriassic
spellingShingle Chase Doran Brownstein
Immanuel Chas Bissell
Species delimitation and coexistence in an ancient, depauperate vertebrate clade
BMC Ecology and Evolution
Coelacanths
Diversity
Speciation
Paleontology
Triassic
title Species delimitation and coexistence in an ancient, depauperate vertebrate clade
title_full Species delimitation and coexistence in an ancient, depauperate vertebrate clade
title_fullStr Species delimitation and coexistence in an ancient, depauperate vertebrate clade
title_full_unstemmed Species delimitation and coexistence in an ancient, depauperate vertebrate clade
title_short Species delimitation and coexistence in an ancient, depauperate vertebrate clade
title_sort species delimitation and coexistence in an ancient depauperate vertebrate clade
topic Coelacanths
Diversity
Speciation
Paleontology
Triassic
url https://doi.org/10.1186/s12862-022-02043-4
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