2003 Seattle Annual Meeting (November 2–5, 2003)

Paper No. 2
Presentation Time: 8:15 AM


MAH, Christopher, Department of Geology, Univ of Illinois, 245 NHB, 1301 W. Green, Urbana, IL 61801, mah@uiuc.edu

Phylogenetic analysis provides the most powerful available tool for understanding bathymetric and spatial migration (i.e., onshore-offshore) patterns within the marine realm. The asteroid family Goniasteridae (Valvatida, Jurassic-Recent) occupies an ideal phylogenetic position for addressing questions of global-scale environmental/paleoenvironmental and biogeographic shifts because it is basal within the largest of three major radiations of post-Paleozoic, crown-group Asteroidea, and it is ancestral to several frequently encountered and ecologically significant families that occur globally. Goniasterids today are found primarily in abyssal and deeper continental shelf environments. A phylogenetic analysis of the Goniasteridae developed from 80 taxa and 80+ morphological characters was developed, recovering a tree topology that shows several recurring, relatively well-supported clades. Pseudarchaster (Jur-Rec) and Paragonaster are basal or near basal to several other clades, including the shallow-water, tropical Oreasteridae and Ophidiasteridae, and they are a sister taxon to a clade containing the deep-water genus Anthenoides . Phylogenetic results further suggest multiple incursions of goniasterid genera into the Atlantic Ocean Basin, and species-level analyses of genera containing Atlantic members supports multiple invasions of the Atlantic Ocean Basin via different routes, including the Indian Ocean as well as through the Panamanian seaway. The tree recovered by the complete analysis is tested by and compatible with known occurrences of fossil goniasterids. Although the fossil record is incompletely known, abundance of goniasterids has been underestimated due to their propensity to disarticulate. Isolated goniasterid ossicles are quite common in certain localities, for example, in shallow-water Eocene to Pleistocene deposits from Florida and the Tropical Atlantic region including Jamaica. These occurrences are important because Atlantic goniasterids found in this region today are restricted to deep-water.