A New Species of Land-locked Freshwater Shrimp of the Genus <i>Neocaridina</i> (Decapoda: Caridea: Atyidae) from Iki Island, Kyushu, Japan.

Abstract

<b>Hsi-Te Shih, Yixiong Cai, Nobuaki Niwa, and Yasuhiko Nakahara (2017)</b> A new species of land-locked freshwater shrimp, <i>Neocaridina ikiensis</i> (Decapoda: Caridea: Atyidae), is described from Iki Island, Kyushu, Japan, based on morphological and molecular evidence. This new species can be distinguished from its congeners by a suite of characters, including rostrum structure, number of post-orbital rostral teeth, male first and second pleopods and telson structure. The molecular evidence of mitochondrial cytochrome oxidase subunit I (COI) shows this species has sufficient interspecific divergence, and its high intraspecific variation suggests that it evolved on this island over a long period of time. Based on the molecular clock estimation, the speciation of <i>N. ikiensis</i> n. sp. is supposed to be related with the quiescent periods of volcanoes on this island. This is the second native species of <i>Neocaridina</i> known, after <i>N. denticulata</i> (De Haan, 1844), from the main islands of Japan.