Neotrygon yakkoei, a new bluespotted maskray (Dasyatidae) from Japan

Abstract

Neotrygon yakkoei (Dasyatidae), a new species of bluespotted maskray from Japan, previously confused with Neotrygon kuhlii (Müller and Henle 1841) or Neotrygon orientalis Last, White and Séret 2016, is described on the basis of 35 specimens [146.4–425.2 mm disc width (DW)] from Japan. The new species is characterized by the following characteristics: greenish brown body in fresh with a single dark mask-like marking between eyes (often indistinct); fewer spots (mean 20.4 spots); small pale blue spots [its diameter 1.2–3.4% (mean 2.6%) of DW] surrounded by dark brown outer rings when fresh; and longer head length 35.9–43.4% (mean 39.1%) of DW. Molecular analysis based on 576 bp of partial COI mitochondrial gene also supports that N. yakkoei is a distinct species from all other congeners, except for Neotrygon vali Borsa 2017, which lacked genetic data. The new species is currently known only from Japan: Hokkaido (Japan Sea and Pacific sides), Wakasa Bay (Japan Sea), the Izu and Ogasawara islands, the Pacific coast of Japan from Sagami Bay to southern Kyushu, and the Osumi, Amami, Okinawa, and Yaeyama islands.