日本列島の太平洋側で採集されたヒメタツHippocampus haemaの形態的および遺伝的特徴

抄録

Hippocampus haema Han, Kim, Kai & Senou 2017 has been found along the coast of the Sea of Japan from Akita Prefecture to Yamaguchi Prefecture in Honshu, the Yatsushiro Sea in Kyushu, and the southern coast of the Korean Peninsula. However, there were no records of this species from the Pacific side of the Japanese Archipelago, with the exception of an example of a partial mitochondrial DNA sequence recently deposited in the DNA data bank. We collected a seahorse specimen from the seagrass bed at Koyadori Fishing Port in Onagawa Town, Miyagi Prefecture, on the Pacific Ocean side on 29 August 2022. Based on morphological characteristics and mitochondrial DNA analysis, this specimen was identified as H. haema. This study provided detailed morphological information and the DNA sequences of the specimen and compared them with previous morphological and DNA data on H. haema and the related species. The values for the 16 morphological characters examined were within the range of previously reported values for H. haema, except for the coronet height from the mid-point of the cleithral ring (CHMC). Small but substantial number of nucleotide substitutions were found between this specimen and previously reported H. haema in Japan, and phylogenetic analysis showed that this specimen belonged to the Korean clade.