Identification genus Lydia (Brachyura: Oziidae) based on molecular and ultrastructure studies of the first male gonopod

Lydia genus belongs to the sub kingdom crustaceans and the class of true crabs. Lydia tenax is The only species from Lydia genus that was found in the Persian Gulf. since in the maritime domain there are a lot of undescribed species so the traditional identification methods based on morphological characteristics is difficult to identify them. The COI gene to identify and determine the limits to species widely used. for this purpose, molecular marker COI gene and ultrastructure first male gonopods was used for the possibility of hidden species among 3 morphotype is shown for this species. therefore sampling from this species were donefrom rocky shores along Bushehr province. then the first male gonopods was separated and photographed by scanning electron microscopy (SEM). for molecular studies samples of DNA extracted by using phenol-chloroform and mitochondrial cytochrome oxidase subunit gene segment (COI) was PCR and sequenced. the results of present study showed that the nucleotide sequence of the mitochondrial gene fragment (COI) is not identical in all samples examined and from these 3 morphotypes, Lydia sp.FCH species was more different with other morphotypes and it was placed in a separate clade. ultrastructure study of the apical part of the first male gonopods showed that there are differences in the apical part of 3 morphtypes. what was obtained from this study showed that It is very important to investigate the first male gonopod and COI gene in separation of species since, identification of species is difficult for many similarities morphology.