Description of Heteromysis (Olivemysis) ekamako sp. nov. (Mysida, Mysidae, Heteromysinae) from a marine cave at Nuku Hiva Island (Marquesas, French Polynesia, Pacific Ocean)

Abstract

Combined faunistic and genetic studies in the marine Ekamako Cave at the southern coast of Nuku Hiva, Marquesas, in the central Pacific, yielded Heteromysis (Olivemysis) ekamako as a new species. This taxon differs from its congeners by a specific combination of morphological characters: flagellate, modified spines dorsally on each of the three segments of the antennular peduncle, a large smooth spine at the tip of only the second male pleopod, series of small flagellate spines along the oblique terminal margin of only the third and fourth male pleopods, and by 2–3 simple spines medially near the statocyst on the endopods of uropods. Although abundant at the entrance of Ekamako Cave, it has not been observed in nine additional submersed marine caves investigated at the Marquesas.