The Department of Geological Sciences Colloquium Series presents Dr. William I. Ausich on “Assembling the Echinoderm Tree of Life—Problems and Some Solutions to the Base of the Echinoderm Tree” on Friday, Feb. 28, at 2 p.m. in Clippinger 205.
Dr. William Ausich
Ausich is Professor Emeritus of Earth Sciences and Director of the Orton Geological Museum at the School of Earth Sciences, Ohio State University.
Abstract: What are the deep phylogenetic roots among the Echinodermata? The Assembling the Echinoderm Tree of Life project is tackling this and other aspects of echinoderm phylogeny. Only five classes of echinoderms are living in today’s oceans, which provides very little information about the Paleozoic origination and divergences of this group that had as many as 21 class-level clades during the Cambrian and Ordovician. Genomic information cannot address this question, and the very high morphologic disparity among echinoderms hinders morphologic comparisons. Questions include: When echinoderms originated from early chordates, were they radiate, helical, or lateralized and from whence did they arise? Are crinoids a clade independent from other stalked echinoderms, or are blastozoans and crinoids a single clade? New fossil evidence supports the hypothesis that the earliest echinoderms were lateralized. Application of the Universal Elemental Homology scheme among stalked echinoderms provides a new means by which to evaluate the phylogeny of stalked echinoderms.
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