TY - JOUR

T1 - The Ordovician diversification of sea urchins

T2 - systematics of the Bothriocidaroida (Echinodermata: Echinoidea)

AU - Thompson, Jeffrey R.

AU - Cotton, Laura J.

AU - Candela, Yves

AU - Kutscher, Manfred

AU - Reich, Mike

AU - Bottjer, David J.

N1 - Funding Information: JRT and DB were funded by US National Science Foundation Grant IOS1240626 to DB and E. Davidson. JRT was also funded by a Royal Society Newton International Fellowship, and a Leverhulme Trust Early Career Fellowship. Funding Information: JRT and DB were funded by US National Science Foundation Grant IOS1240626 to DB and E. Davidson. JRT was also funded by a Royal Society Newton International Fellowship, and a Leverhulme Trust Early Career Fellowship. Thanks are due to A. Molineux and A. Thompson at the University of Texas Non-vertebrate Paleontology Lab, in Austin, T. Ewin at the Natural History Museum, London, G. Mirantsev and S. Rozhnov at the Palaeontological Institute of the Russian Academy of Sciences, Moscow and C. Neumann at the Museum für Naturkunde, Berlin, for access to bothriocidaroid specimens that were photographed and/or measured for the present study. V. Arkadiev at St. Petersburg State University, S. Meng at Greifswald University and I. Zorn at GBA Vienna provided specimen numbers, and J. Kobylinska provided specimen numbers for material in the Polish Academy of Sciences. S. Donovan at Naturalis Biodiversity Center, Leiden, is thanked for alerting JRT to Eggink (1991). JRT is further indebted to G. Mirantsev and to E. Larina, University of Southern California, for help with Russian translation of Männil (1962). L Weist, Baylor University, provided valuable assistance in obtaining SEM micrographs of species of Bothriocidaris. This is a contribution to IGCP project 735 ‘Rocks and the Rise of Ordovician Life: Filling knowledge gaps in the Early Palaeozoic Biodiversification’. Finally, we thank D. Wright, an anonymous reviewer and Associate Editor T. Ewin, for their insightful comments. JRT and DB were funded by US National Science Foundation Grant IOS1240626 to DB and E. Davidson. JRT was also funded by a Royal Society Newton International Fellowship, and a Leverhulme Trust Early Career Fellowship. Publisher Copyright: © The Trustees of the Natural History Museum, London 2022. All rights reserved.

PY - 2022

Y1 - 2022

N2 - The echinoids of the order Bothriocidaroida represent the initial burst of sea urchin diversification. They were the first echinoids to achieve widespread biogeographical dispersal and achieved high levels of species richness compared to other clades of stem group echinoids. Following long-standing controversy regarding their phylogenetic affinities within the phylum Echinodermata, bothriocidaroids are now regarded as echinoids. The species- and genus-level phylogenetic relationships of the bothriocidaroids, are, however, less clearly known. We herein compile a database of bothriocidaroid occurrences, undertake detailed phylogenetic analyses of all named species within the Bothriocidaroida, and provide updated diagnoses for all species. Our phylogenetic analysis includes species belonging to three genera: Bothriocidaris, Unibothriocidaris and Neobothriocidaris. Furthermore, we describe a new species, Neobothriocidaris pentlandensis sp. nov., from the Silurian of Scotland and Sweden, using micro-computed tomography and scanning electron microscopy. This species has implications for understanding the diversity dynamics of bothriocidaroids before and after the Late Ordovician mass extinction and the palaeobiogeographical distribution of bothriocidaroids in the Silurian. Using Bayesian and parsimony-based phylogenetics, we demonstrate that Neobothriocidaris is a distinct clade, and depending upon the analytical technique, Unibothrioidaris and Bothriocidaris are also resolved as monophyletic. Unibothriocidaris appears to have become extinct in the Sandbian, while Neobothriocidaris and Bothriocidaris survived the Late Ordovician extinction events and lasted at least until the Ludlow. Furthermore, we performed statistical time-calibration of our phylogenetic trees and show that bothriocidaroids originated in the Dapingian or Darriwilian, diversifying in the Darriwilian to Sandbian and reaching peak diversity in the Sandbian and Katian. This Sandbian and Katian peak is similar to that observed in other echinoderm clades, as well as other animal groups during the Ordovician radiation, and may be linked to heightened sea level and expansive tropical shelves present in the Upper Ordovician, and to new inhabitable environments linked with Ordovician oxygenation. http://zoobank.org/urn:lsid:zoobank.org:pub:B55D0B22-D4AB-474A-80B9-D19BB43107F0.

AB - The echinoids of the order Bothriocidaroida represent the initial burst of sea urchin diversification. They were the first echinoids to achieve widespread biogeographical dispersal and achieved high levels of species richness compared to other clades of stem group echinoids. Following long-standing controversy regarding their phylogenetic affinities within the phylum Echinodermata, bothriocidaroids are now regarded as echinoids. The species- and genus-level phylogenetic relationships of the bothriocidaroids, are, however, less clearly known. We herein compile a database of bothriocidaroid occurrences, undertake detailed phylogenetic analyses of all named species within the Bothriocidaroida, and provide updated diagnoses for all species. Our phylogenetic analysis includes species belonging to three genera: Bothriocidaris, Unibothriocidaris and Neobothriocidaris. Furthermore, we describe a new species, Neobothriocidaris pentlandensis sp. nov., from the Silurian of Scotland and Sweden, using micro-computed tomography and scanning electron microscopy. This species has implications for understanding the diversity dynamics of bothriocidaroids before and after the Late Ordovician mass extinction and the palaeobiogeographical distribution of bothriocidaroids in the Silurian. Using Bayesian and parsimony-based phylogenetics, we demonstrate that Neobothriocidaris is a distinct clade, and depending upon the analytical technique, Unibothrioidaris and Bothriocidaris are also resolved as monophyletic. Unibothriocidaris appears to have become extinct in the Sandbian, while Neobothriocidaris and Bothriocidaris survived the Late Ordovician extinction events and lasted at least until the Ludlow. Furthermore, we performed statistical time-calibration of our phylogenetic trees and show that bothriocidaroids originated in the Dapingian or Darriwilian, diversifying in the Darriwilian to Sandbian and reaching peak diversity in the Sandbian and Katian. This Sandbian and Katian peak is similar to that observed in other echinoderm clades, as well as other animal groups during the Ordovician radiation, and may be linked to heightened sea level and expansive tropical shelves present in the Upper Ordovician, and to new inhabitable environments linked with Ordovician oxygenation. http://zoobank.org/urn:lsid:zoobank.org:pub:B55D0B22-D4AB-474A-80B9-D19BB43107F0.

KW - Bayesian

KW - Bothriocidaris

KW - extinction

KW - Neobothriocidaris

KW - phylogeny

KW - sea urchin

U2 - 10.1080/14772019.2022.2042408

DO - 10.1080/14772019.2022.2042408

M3 - Journal article

AN - SCOPUS:85129166330

VL - 19

SP - 1395

EP - 1448

JO - Journal of Systematic Palaeontology

JF - Journal of Systematic Palaeontology

SN - 1477-2019

IS - 20

ER -