Careproctus globulus Chernova, Thiel & Eidus, 2020

Chernova, Natalia, Thiel, Ralf & Eidus, Irina, 2020, Four new species of Careproctus (Cottoidei: Liparidae) from the deep-water vicinity of the southern Kuril Islands (Western North Pacific), Zootaxa 4821 (1), pp. 71-87 : 84-85

Careproctus globulus Chernova, Thiel & Eidus , new species

English name: Globular snailfish

( Fig. 8 C , 9 , 10 B )

urn:lsid:zoobank.org:act:F1EEAF80-9E78-41E8-A762-2EAA18FC542E

Holotype: ZMH 26374, juvenile, 43 mm SL, Pacific entrance of the Bussol Strait, 46°36.465´ N, 151°34.6´ E, Agassiz trawl, depth 2350–2358 m, 24 July 2015, R / V “ Akademik M. A. Lavrentyev ”, cruise 71, station 8–7, collector I. Eidus.

Diagnosis. A species of Careproctus with the following combination of characters: vertebral column with a deep curve, vertebrae 46 (8+38). Pleural ribs absent. D 42 (including 5 precaudal), A 36, P about 24, C 8 (principal rays). Hypural plate unslitted. Pores 2-5-6-1. Head 24.4 % SL, preanal 34.9 % SL; pelvic disk 38 % lc. Pale pinkish when fresh, head and peritoneum black.

Description. Fresh specimen ( Fig. 8 C ). Body pale, translucent. Head massive globular. Anterior part of head and belly black because of ink-black orobranchial cavity and peritoneum, tail pale pinkish.

Preserved specimen. Anterior part of body globular, caudal part low and elongated. Head deep and wide (76 and 71 % lc). Snout short and abruptly blunt. Snout skin fold does not cover the upper jaw. Nostril at level of upper half of eye. Eye large (29 % lc). Mouth terminal, horizontal. Oral-cleft end under anterior margin of pupil. Chin massive, angular when viewed from below. Teeth simple, with small lateral shoulders, in a few regular oblique rows. In anterior part of jaws are 5 teeth in oblique rows. Gill slit reaching to the 3 rd pectoral-fin ray. Pore formula unusual: nasal 2, infraorbital 5, preoperculomandibular 6, suprabranchial 1.

Radiograph. Vertebral column with a deep curve. Vertebrae 46 (precaudal 8, caudal 38). Pleural ribs absent. Dorsal-fin rays 42 (precaudal 5). Anal-fin rays 36, the first ray inserts behind the 2 nd haemal spine. Rayless pterygiophores absent; anteriormost dorsal-fin ray inserted between neural spines 3 and 4. Hypural plate unslitted. C 8 (4+4) principal.

Dorsal and anal fins low. Pectoral fin notched; lower lobe rays elongated and filamentous at the ends. Pectoral fin includes about 24 rays (about 17 in upper lobe, 7 in lower lobe). Pelvic disk not large. Anus twice closer to disk than to anal-fin origin.

Preserved specimen pale, disk uncolored. Peritoneum and orobranchial cavity black.

Distribution. The type specimen was found on the Pacific side of the Bussol Strait at a depth of 2350–2358 m (in the same trawl as C. pulcher ).

Environmental conditions. Same as for C. pulcher .

Etymology. The name is derived from the Latin word “globula”, as the anterior part of the body is almost spherical.

Comparative note. Globular body and strongly curved vertebral column are among the main characters of the liparid genus Psednos Barnard ( Chernova 2001; Andriashev 2003). However, Careproctus globulus differs from all Psednos species by the presence of the pelvic disk (absent in the latter) and by an un-transformed structure of the cephalic sensory system, as the disposition of pores is typical for Careproctus but not for Psednos (i.e., the coronal pore is absent; the upper nasal pore opens lower than the nostril). Additionally, the holotype of 43 mm SL is a juvenile, and Psednos includes dwarf species which are already adult at this length.

Not a single species of Careproctus is known with the following combination of characters: vertebrae 46 (abdominal 8), principal caudal-fin rays 8, absence of pleural ribs, one suprabranchial pore, and strongly curved vertebral column.

Careproctus globulus was found in the same trawl as C. pulcher , but undoubtedly, it is a new species. If compared with the juvenile C. pulcher , С. globulus differs from the latter by its spherical body and deep curve of vertebral column ( Fig. 10 B ), by the absence of pleural ribs, number of principal caudal-fin rays (8 vs. 10) and by its black peritoneum.

Figures

FIGURE 8. Fresh juveniles: A–B, Careproctus pulcher sp. nov., 38 and ca. 48 mm SL; C, holotype of Careproctus globulus sp. nov., 43 mm SL, ZMH 26374.

FIGURE 9. Careproctus globulus sp. nov.: A–B, holotype, ZMH 26374, juvenile 43 mm SL.

FIGURE 10. Radiographs of juveniles: A, paratype of Careproctus pulcher sp. nov., 38 mm SL, ZMH 26371; B, holotype of Careproctus globulus sp. nov., 43 mm SL, ZMH 26374.