Molecular Phylogeny of the Coral-Reef Echinoderms

Abstract

: Echinoderms are one of the dorminant inverterbrates of Indo-Westpacific coral reefs. In order to understand phylogenetic relationship among the tropical Echinoderms, we analyzed DNA sequence of 12 Asteroidea species, 10 Echinoids and 10 Holothuroids sampled from Guam. One to three individuals of each species were used for DNA sequencing of mitochondrial cytochrome oxidase subunit (COI) and 16S genes. Molecular phylogeny among the species was reconstructed by the method of ML, ME, MP using the PAUP* program. The trees were made for each class of Echinoderms. The tree of the class Echinoidea shows that three species of family Diadematidae made a clade district from other families and that H. mammailatus is closely related with the family Echinometridae. In the tree of the class Asterozoa, six species of family Ophidiasteridae formed a monophyletic clade among the 12 species investigated. In the class Holothuroidea, two species of family Stichopodidae were closely related with T. ananas. Two Bohagchia species made a monophyletic clade while the species of family Holothuroidae show paraphyletic relationships. This study can be expanded to echinoderms in the other tropical regions to examine the evolutionary history of the coral reef Echinoderms