Occurrence and biogeographic significance of Heliaster (Echinodermata: Asteroidea) from the Pliocene of southwest Florida

Abstract

Whole body asteroid fossils are rare in the geologic record and previously unreported from the Cenozoic of Florida. However, specimens of the extant species,Heliaster microbrachiusXantus, were recently discovered in upper Pliocene deposits. This marks the first reported fossil occurrence of the monogeneric Heliasteridae, a group today confined to the eastern Pacific. This discovery provides further non-molluscan evidence of the close similarities between the Neogene marine fauna of Florida and the modern fauna of the eastern Pacific. The extinction of the heliasters in the western Atlantic is consistent with the pattern of many other marine groups in the region which suffered impoverishment following uplift of the Central American isthmus.