World Travelers: DNA Barcoding Unmasks the Origin of Cloning Asteroid Larvae from the Caribbean

Abstract

The identity of wild cloning sea star larvae has been a mystery since they were first documented in the Caribbean. The most commonly collected cloning species was thought to belong to the Oreasteridae, on the basis of similarity with sequences fromOreaster reticulatusandOreaster clavatus. This larval form has recently been linked to a rare benthic juvenile. As part of two larger DNA barcoding projects, we collected cloning asteroid larvae from the Caribbean coast of Panama and compared them to a large reference database of tropical echinoderms. Morphological and DNA barcode data from the cytochromecoxidase subunit I gene demonstrated that Panamanian larvae belonged to the same operational taxonomic unit as those recovered in previous studies of cloning larvae from the Caribbean. Much to our surprise, sequences from these larvae clearly identified them as belonging toValvaster striatus, a species typically considered to be endemic to the Indo-West Pacific. A lineage ofMithrodia clavigerathat occurs in both the Caribbean and the Indo-West Pacific also has cloning larvae, suggesting that this unusual life history has allowed larvae to pass around the Cape of Good Hope and the Benguela upwelling region, which is a barrier to dispersal for most tropical marine invertebrates.