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

Asteroidae, or starfish, is one of the classes of phylum Echinodermata that its phylogenetic relationships have not been studied in the Persian Gulf so far. In this research, the morphological identification, molecular analysis and phylogeny of 40 asteroid samples were studied from the northern islands of the Persian Gulf. For this purpose, starfish samples were identified using morphological characteristics. The molecular identification was performed based on two fragments of mitochondrial cytochrome oxidase subunit I (COI) and mt 16S rRNA. The phylogenetic relationships of asteroids were analyzed using maximum likelihood, maximum parsimony and Bayesian methods. Eleven species of starfishes belonging to 6 genera as well as 5 families have been identified including Luidia hardwicki, Astropecten hemprichi, Astropecten indicus, Astropecten polyacanthus phragmorus, Astropecten polyacanthus polyacanthus, of Culcita novaeguineae, Pentaceraster mammillatus, Linckia laevigata, Linckia multifora, Aquilonastra iranica and Aquilonastra watersi. Since the species of Linckia laevigata (orange-green morph) and a specimen of Astropecten polyacanthus polyacanthus have been identified based on molecular analysis, this technique can be a useful tool in asteroids along with morphological studies. The obtained interspecies distances in genera Luidia and Astropecten suggest cryptic speciation might have occurred in these genera. 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 morphological taxonomic and phylogenetic analyses.