Phylogeny and genetic diversity of Caspian pond turtle (Mauremys caspica Gmelin, 1774) in Chaharmahal va Bakhtiari province, Iran

The earliest known turtles are from around 215 million years ago, making turtles one of the oldest reptile groups. So far, about 351 turtle species have been reported worldwide, of which about 40% have been introduced as threatened species in the IUCN Red List. Caspian pond turtle (Mauremys caspica) has a relatively wide distribution in the northern and western Iran. Survival of this species has been severely threatened due to habitat destruction, pollution, and water resource mismanagement in Iran. Here, we investigated the genetic diversity and phylogeny of M. caspica in Chaharmahal va Bakhtiari province. A 1040-bp fragment of the cytochrome b gene was sequenced in 12 individuals across the province. A dataset was created using our sequences together with an additional 23 sequences downloaded from GenBank. Based on phylogenetic trees (maximum likelihood and Bayesian inference), the sequences of M. caspica and M. rivulata were separated with the highest bootstrap and posterior probability. All Caspian pond turtle's sequences fell into two clades: Eastern and Western. The findings revealed that turtles from Chaharmahal va Bakhtiari belong to only one haplotype (MCE2) within the eastern clade. The AMOVA analysis, based on Caspian pond turtle's sequences, show that 82.12% of the overall variation is estimated among the identified clades (Eastern and Western). None of the neutrality indices (Fu’s FS، Tajima’s D and Ramos-Onsins and Rozas’ R2) revealed negative and significant values, and thus, the sudden demographic expansion was rejected in the clades of M. caspica. Caspian pond turtle population, based on cytochrome b, in the study area can be regarded to an evolutionarily significant unit.