Abstract

Understanding the distribution of taxa in space and time is key to understanding diversity dynamics. The fossil record provides an avenue to assess these patterns on vast timescales and through major global changes. The Eublastoidea were a conservatively plated Paleozoic echinoderm clade that range from the middle Silurian to the end-Permian. The geographic distribution of the eublastoids, as a whole, has been qualitatively assessed but has historically lacked a quantitative analysis. This is the first examination of the Eublastoidea using probabilistic methods within the R package BioGeoBEARS to assess macroevolutionary trends. Results provide an updated understanding of eublastoid diversity with new peaks and troughs in diversity through their evolutionary history. Lithology is examined in an evolutionary framework and does not have clear evolutionary trends, and there is much work to be done regarding environmental preferences. Biogeographic patterns do not recover precise group origins but do support the previous work that outlines Eublastoidea as a Laurentian clade. Sympatric speciation events dominant the clade's history but are likely exaggerated due to the highly combined areas. Vicariance events are rare and restricted to the Silurian and Devonian, and dispersal events are more common throughout the evolutionary history. Pathways allowing for lineage migrations are noted between southern Laurussia and China in the Devonian and Carboniferous and southern Laurussia and eastern Gondwana in the Carboniferous. Future work will include the addition of more non-Laurentian species into the estimated phylogeny to better estimate these global patterns.

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