Phylogeny, evolution, and biodiversity of the Goniasteridae (Asteriodea; Echinodermata)

Phylogenetic analysis is the most powerful tool for understanding bathymetric and spatial migrations (i.e., onshore-offshore) patterns within the marine realm. The Goniasteridae occupies an ideal phylogenetic position in which to address questions regarding global scale paleoenvironmental and biogeographic shifts. Goniasterids reside within the Valvatoidea, the largest of three major radiations of post-Paleozoic, crown-group Asteroidea. Phylogenetic location is ancestral to several frequently encountered and ecologically significant starfish groups found throughout all of the world's ocean basins. Goniasterid starfishes are predominantly deep-sea taxa, occupying abyssal and continental shelf environments.; A phylogeny of the Goniasteridae was performed, including 98 taxa and 123 morphological characters. The cladistic analysis resulted in 32 most parsimonious trees which displayed broad agreement except for variable positions in five clades. Branch support was low for several branches but homoplasy was rampant at the genus-level analysis and smaller species-level studies demonstrated stronger support for individual genera. In addition to previously unrecognized grouping/clades, several subgroupings previously established within the Goniasteridae are supported by the analysis.; Phylogenetic results demonstrated bathymetric shifts present across several lineages, demonstrating both onshore-offshore and offshore-onshore patterns. Results also showed distribution patterns of goniasterid genera across the Indo-Pacific, Atlantic, and Southern Oceans. More finely resolved biogeographic patterns were available from species-level analyses. Phylogenetic patterns show broad agreement with goniasterid fossil occurrence. Derived goniasterid taxa show largely Cretaceous and Cenozoic occurrence whereas basal goniasterid genera occur in the Jurassic.; To demonstrate more finely resolved phylogenetic patterns, species-level phylogenetic analyses were performed for Iconaster + Glyphodiscus and for Circeaster. These demonstrated bathymetric shifts at a species level in the former and in the latter, biogeographic shifts associated with allopatric barriers formed by historical geologic events such as the closure of the Panamanian Isthmus.; Comprehensive phylogenetic hypotheses for the Goniasteridae provides a strong context for establishment of new genera and species. Goniasterid starfish represent among the most poorly known of asteroid groups. Only 75% of the goniasterid fauna was known at the end of the 20th Century. This study recognizes much of this undescribed biodiversity, including 10 new genera and six new species.