Skip to main content
Article
Estimating Dispersal and Evolutionary Dynamics in Diploporan Blastozoans (Echinodermata) Across the Great Ordovician Biodiversification Event
Paleobiology
  • Adriane R. Lam, University of Massachusetts
  • Sarah L. Sheffield, University of South Florida
  • Nicholas J. Matzke, University of Auckland
Document Type
Article
Publication Date
1-1-2020
Digital Object Identifier (DOI)
https://doi.org/10.1017/pab.2020.24
Disciplines
Abstract

Echinoderms make up a substantial component of Ordovician marine invertebrates, yet their speciation and dispersal history as inferred within a rigorous phylogenetic and statistical framework is lacking. We use biogeographic stochastic mapping (BSM; implemented in the R package BioGeoBEARS) to infer ancestral area relationships and the number and type of dispersal events through the Ordovician for diploporan blastozoans and related species. The BSM analysis was divided into three time slices to analyze how dispersal paths changed before and during the great Ordovician biodiversification event (GOBE) and within the Late Ordovician mass extinction intervals. The best-fit biogeographic model incorporated jump dispersal, indicating this was an important speciation strategy. Reconstructed areas within the phylogeny indicate the first diploporan blastozoans likely originated within Baltica or Gondwana. Dispersal, jump dispersal, and sympatry dominated the BSM inference through the Ordovician, while dispersal paths varied in time. Long-distance dispersal events in the Early Ordovician indicate distance was not a significant predictor of dispersal, whereas increased dispersal events between Baltica and Laurentia are apparent during the GOBE, indicating these areas were important to blastozoan speciation. During the Late Ordovician, there is an increase in dispersal events among all paleocontinents. The drivers of dispersal are attributed to oceanic and epicontinental currents. Speciation events plotted against geochemical data indicate that blastozoans may not have responded to climate cooling events and other geochemical perturbations, but additional data will continue to shed light on the drivers of early Paleozoic blastozoan speciation and dispersal patterns.

Comments

Data available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.4tmpg4f6j

Rights Information
Creative Commons Attribution 4.0
Citation / Publisher Attribution

Paleobiology, v. 47, issue 2, p. 198-220

Citation Information
Adriane R. Lam, Sarah L. Sheffield and Nicholas J. Matzke. "Estimating Dispersal and Evolutionary Dynamics in Diploporan Blastozoans (Echinodermata) Across the Great Ordovician Biodiversification Event" Paleobiology Vol. 47 Iss. 2 (2020) p. 198 - 220
Available at: http://works.bepress.com/sarah-sheffield/16/