A new cave-dwelling hadzioid amphipod (Senticaudata, Hadzioidea, Melitidae) from sulfidic groundwaters in Iran

Cave systems fed with hydrogen sulfide-rich groundwater are unique chemoautotrophy-dependent ecosystems. Although globally widespread and known to harbor unique subterranean metazoan communities, they have mostly been studied in Europe and North America, less so in Asia. Here, we report on a discovery of a new species of amphipod crustacean from sulfidic waters of Tashan-Chah Kabootari aquifer from Zagros Mountains in Iran. The new species corresponds morphologically to the melitid genus Tegano Barnard & Karaman, 1982, and Tegano tashanensis sp. nov. is the first amphipod from the superfamily Hadzioidea found exclusively in sulfidic water. Phylogenies derived from the mitochondrial COI and the nuclear 28S rRNA sequences recover T. tashanensis sp. nov. in a clade that contains representatives of the currently para- or polyphyletic genera Barnardomelita, Brachina, Josephosella, and Tegano indicating the need for a revised melitid genus level systematics. This clade comprises marine, freshwater and subterranean species globally distributed in regions that were connected by the ancient Tethys Sea. As such, these taxa may be suitable biogeographic models for studying past dispersal, vicariance and multiple colonization of inland groundwaters.