Morphological and molecular investigation of some xanthid crabs from the Egyptian coast of the Red Sea

Abstract

Family Xanthidae comprises 15 subfamilies and over 600 accepted species; they are represented well in the foreshore marine environments. Members of family Xanthidae are multi-colored crabs, usually inhabiting rocky coasts, coral reefs, and mud flats, all of which are well represented along the Egyptian coast of the Red Sea. Here, we utilized cytochrome oxidase subunit I (COI) sequences combined with morphology to provide information on some xanthid specimens collected from the Egyptian coast of the Red Sea. Six species within four genera (Leptodius, Etisus, Cyclodius, Chlorodiella) were collected. Genetic distances combined with morphological analyses showed intraspecific variations between two morphotypes of Leptodius exaratus. Two Etisus species were examined, E. laevimanus and E. sp. The latter Etisus sp. was close to E. frontalis, especially with regard to frontal lobe morphology, but different in male's first gonopod, with interspecific genetic distances. We also identified Chlorodiella nigra and C. laevissima. Obtained genetic distances between two morphotypes of Cyclodius granulatus revealed that these morphotypes are also likely cases of intraspecific variation. The results of this study should provide a basis for future work on family Xanthidae along the coasts of the Red Sea, which is needed as data remain scant.