Morphological identification and phylogenetic analysis of Asteroidea (Echinodermata) in the northern coast of the Persian Gulf

Asteroidae, or starfish, have about 1900 extant species as one of the classes of phylum Echinodermata. Thirty specimens of starfishes were collected from the northern islands of the Persian Gulf for morphological identification, molecular analysis and phylogeny. The first starfish samples were distinguished morphologically then they were identified after DNA extraction by CTAB and Chelex 5% and its amplification based on 16S rRNA gene in molecular analysis. The phylogenetic relationships of asteroids were analyzed using maximum likelihood, maximum parsimony and Bayesian methods. The morphological and molecular identifications displayed 6 species of Luidia hardwicki, Astropecten indicus, Aquilonastra watersi, Aquilonastra iranica, Linckia laevigata and Pentaceraster mammillatus belonging to 5 genera and 2 families. Our results showed Luidia hardwicki and Astropecten indicus species were grouped with sequences of the same species from GenBank in separate clades. As Aquilonastra watersi and Pentaceraster mammillatus in 16S rRNA gene are reported for the first time so their sequences were placed in sister groups with Aquilonastra yairi and Pentaceraster cumingi, respectively. Since the species of Linckia laevigata species (orange-green morph) have been identified based on molecular analysis, this technique along with morphological studies can provide more complete results for Asteroids. The results of Asteroidae classifications at the genus and family levels indicated phylogenetic tree of mt 16S rRNA gene based on Bayesian method is consistent with previous phylogenetic results.