Abyssobrotula hadropercularis Ohashi & Nielsen, 2016, sp. nov.

• Main Authors: Ohashi, Shinpei, Nielsen, Jørgen G.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2016
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Actinopterygii; Ophidiiformes; Ophidiidae; Abyssobrotula; Abyssobrotula hadropercularis; Kamchatka
• Online Access: https://zenodo.org/record/6063884; https://doi.org/10.5281/zenodo.6063884

Abyssobrotula hadropercularis sp. nov. (Figs. 1–6, Table 1) Holotype. NSMT-P 121429, 200 mm SL, female, Kuril-Kamchatka Trench (46 ° 55.53 ′N, 160 ° 2.84 ′E – 46 ° 54.14 ′N, 160 ° 1.99 ′E), R/V Hakuho-maru, st. NBD- 2, beam trawl, 5204–5205 m, 31 May 2014. Paratype. NSMT-P 121428, 149 mm SL, male, Kuril-Kamchatka Trench (47 ° 0.22 ′N, 160 ° 2.62 ′E – 47 ° 0.91 ′N, 160 ° 1.29 ′E), R/V Hakuho-maru, st. NBD- 1, beam trawl, 5179–5223 m, 27 May 2014. Diagnosis and similarity. Abyssobrotula hadropercularis differs from A. galatheae, the only other species of the genus, by the following characters (A. galatheae mentioned in parenthesis): Opercular spine pointed and strong (vs. flat and weak), pectoral fin rays 14–15 (vs. 10–11), head length 22.0– 22.5 % SL (vs. 17.5–19.5), diameter of pigmented eye 1.2–1.3 % SL (vs. 0.7–0.9), preanal length 42.5 % SL (vs. 33.0– 41.5), prepelvic length 14.0– 14.5 % SL (vs. 10.5–12.5), rakers on anterior gill arch robust and close-set (vs. thin and well separated). Description. Selected meristic and morphometric characters are shown in Table 1. The description is based on the holotype, differences observed in the paratype mentioned in parenthesis. Body compressed with tapering tail, depth at anus about 7 times in SL. Head inflected downward, its length slightly less than half preanal-fin length. Cycloid scales in some parts of head and body (Fig. 2), but empty scale pockets indicate that most areas of body and head covered with scales. Judging from the loose skin, snout and dorsal part of head seem to have been swollen. Two pairs of nostrils with wide opening between tip of snout and eye: Anterior nostril circular at tip of snout and posterior nostril between anterior nostril and eye, slightly exposing lateral ethmoid. Eye small, 3.8 (4.6) times in snout length. Mouth inferior, upper jaw long, posterior margin extending well behind eye. Supramaxilla elliptical. Opercle robust, but its dorsal margin extremely thin making rudimentary bulge above spine; its spine pointed and strong not ...