A new fish of the genus Krusensterniella (Zoarcoidei: Zoarcidae) from the Kuril Islands

Abstract

A new species of prickled eelpouts of the genus Krusensterniella Schmidt, 1904 (subfamily Gymnelinae Gill, 1863) from the waters of the Kuril Islands (Western North Pacific) is described. Moppet eelpout K. infans sp. nov. differs from other species by a combination of characters. Vertebrae are numerous (124 versus 100–122), as well as all spiny rays of the dorsal fin (77 vs. 40–74); number of preoperculomandibular pores is reduced (6 vs. 7 in most species); pungent spines of the dorsal fin (X in number) are located posteriorly (D-fin formula 67 X 44). The holotype, a juvenile with a length of TL 83 mm, is found in the southern group of the Kuril Islands (Urup Strait) at a depth of 240 m. The ancestral form of the prickled eelpouts probably lived in the boreal Pacific waters near the Japanese Islands, where the generalized K. squamosa Chernova, 2022 is found. Other species with similar characters, K. maculata Andriashev, 1938, K. kurilensis Chernova, 2022, and K. pseudomaculata Chernova, 2022, with relatively low number of vertebrae and pungent spines, may have derived in nearby waters, the Sea of Japan and the southern Kuril Islands. Dispersion to the north (into the Sea of Okhotsk) led to the speciation of two pairs of prickled eelpouts. One pair is K. notabilis Schmidt, 1904 and K. infans with low number of pungent spines but numerous vertebrae (113–124); the other pair is K. multispinosa Soldatov, 1922 and K. pavlovskii Andriashev, 1955 with a relatively low number of vertebrae but multiple pungent spines (XV–XXV). This may mean that northward dispersion events could have occurred at least twice.