Careproctus orri Kai &Tashiro, 2021

Kai, Yoshiaki, Endo, Hiromitsu, Tashiro, Fumihito & Nakayama, Naohide, 2021, Two new species of snailfishes of the genus Careproctus (Cottoidei: Liparidae) from the western North Pacific Ocean with a range extension of Careproctus brevipectoralis, Zootaxa 4951 (2), pp. 361-371 : 366-367

Careproctus orri Kai &Tashiro sp. nov.

New Japanese name: Kujira-kon’nyaku-uo

Figs. 1C , 2B, 2E , 3B ; Table 1

urn:lsid:zoobank.org:act:05C338DF-2BA4-4EB8-AE56-A7B012BBFE96

Holotype. NSMT-P 53657 , 121.0 mm SL, female, 37.9512ºN, 141.2202ºE, off Miyagi, Japan, 808 m depth, T / V Tanshu-maru , 13 Apr. 1996, coll. by Gento Shinohara.

Paratype. HUMZ 201730, 143.4 mm SL, female, 40.3302ºN, 142.3003ºE, off Iwate, Japan, 640 m depth, 11 Oct. 2007 .

Diagnosis. A species of Careproctus with the following combination of characters: vertebrae 58–60; dorsal-fin rays 52–53, anteriormost dorsal-fin pterygiophore without ray, inserted between neural spines 3 and 4; anal-fin rays 47–49; pectoral-fin rays 34–35; pectoral fin with distinct notch; cephalic pores 2-6-7-2, chin pores single, unpaired; gill slit extending ventrally to 5 th or 6 th pectoral-fin ray; teeth strongly trilobed; pyloric caeca at least 15 to 21; peritoneum white, stomach dark.

Description. Counts and measurements are shown in Table 1 . Paratype data are given in parentheses if different from the holotype.

Body humpbacked and compressed, tapering posteriorly, deepest at nape ( Fig. 1C ). Skin thin, lacking prickles. Head compressed, strongly sloping from nape to snout. Snout blunt, slightly protruding beyond tip of upper jaw. Mouth moderate in size, terminal; maxilla extending to anterior margin of pupil; oral cleft not reaching anterior rim of orbit. Premaxillary teeth strongly trilobed in 11 (9) oblique rows; inner teeth larger ( Fig. 2B ). Mandibular teeth strongly trilobed in 8 oblique rows; inner teeth larger. Diastema absent at symphysis of upper and lower jaws. Orbit and pupil rounded. Nostril single, with short tube at level with middle of orbit. Cephalic sensory pores small: nasal pores 2, maxillary pores 6, preoperculomandibular pores 7, suprabranchial pores 2; cephalic pore pattern 2-6-7-2. Chin pores single, unpaired ( Fig. 3B ). Coronal pore absent. Upper margin of gill slit at level with upper portion of orbit, extending ventrally to pectoral-fin ray 5 (6). Opercular flap slightly angular. Pyloric caeca 21 (at least 15 in paratype), on both left and right sides of visceral cavity.

Vertebrae 60 (58) (11+47–49). Pleural ribs 2, long, present on vertebrae 9–10; anterior rib somewhat slender. Dorsal-fin rays 53 (52). Anteriormost dorsal-fin pterygiophore without ray, inserted between neural spines 3 and 4; dorsal-fin origin above anus, posterior to above tip of opercle. Anal-fin rays 49 (47); anal-fin origin below 8 th dorsalfin ray. Two anal-fin pterygiophores anterior to first haemal spine, each bearing a single ray. Membrane of posterior dorsal- and anal-fin rays attached about equidistant on caudal fin. Caudal fin rounded (broken in paratype). Principal caudal-fin rays 10, single dorsal and anal procurrent rays present (absent). Hypurals and parhypural fused into single plate without slit.

Pectoral fin deeply notched, with 35 (34) rays; upper lobe of 28 rays extending to anal-fin origin (or just beyond), dorsalmost ray lengthening to 6 th (5 th) ray, more ventral rays gradually shortening to shortest ray of notch; lower lobe with 7 (6) thickened rays extending beyond anus, 6 th (5 th) ray from the ventralmost longest, lower rays exserted; rays in notch slightly more widely spaced than rays of lobes. Uppermost pectoral-fin base level with ventral rim of orbit; symphysis of pectoral-fins below posterior rim of orbit. Proximal pectoral radials 4, relatively small and rounded, upper 3 close together, 4th slightly separated from 3rd (3+1) ( Fig. 2E ). No interradial fenestrae between proximal radials. Scapula broad with robust helve. Coracoid triangular with broad lamina. Distal radials present at base of all pectoral-fin rays, except for uppermost and lowermost rays. Pelvic disk moderately large, round, below midway between posterior rim of orbit and gill slit. Anus below gill slit, closer to pelvic disk than anal-fin origin.

Coloration: Live coloration unknown. When preserved, head and body pale brown ( Fig. 1C ). Fins pale brown, distal margins of dorsal, anal, and caudal fins dark. Peritoneum white; stomach dark.

Distribution. Western Pacific Ocean, off the Pacific coast of Tohoku District, northern Honshu Is., Japan, in depths of 640– 808 m.

Etymology. The specific epithet “ orri ” is named for Dr. James W. Orr of Alaska Fisheries Science Center (NOAA), who has contributed greatly to the systematics of snailfishes.

Remarks. The present new species is most similar to Careproctus rausuensis Machi, Nobetsu & Yabe, 2012 in having trilobed teeth, a cephalic pore pattern of 2-6-7-2, single and unpaired chin pores, a pectoral fin with a notch, and counts of dorsal- (52–53 in C. orri sp. nov. vs. 50–55 in C. rausuensis ), anal- (47–49 vs. 45–48), principal caudal- (10 vs. 10–11) and pectoral-fin rays (34–35 vs. 33–37) ( Machi et al. 2012; this study). However, C. orri can be distinguished from C. rausuensis in having a humpbacked body (vs. a rounded dorsal profile), relatively small cephalic pores (vs. large pores), and a small gill slit, extending ventrally to pectoral-fin ray 5–6 (vs. a large gill slit, extending ventrally to pectoral-fin ray 7–11) ( Machi et al. 2012; this study). The new species is further distinguished from the latter in having a more compressed body (body width: 8.9–10.1% SL vs. 17.0–20.1% SL). Careproctus mollis Gilbert & Burke, 1912 , only known from the holotype (off Attu Island in the western Aleutian Islands) and two additional specimens (off Agattu Island in the western Aleutian Islands), is also similar to C. orri sp. nov. in having a humpbacked body, trilobed teeth, a cephalic pore pattern of 2-6-7-2, chin pores in a single pit, a pectoral fin with a notch. Unlike the new species, however, the position of anteriormost dorsal-fin pterygiophore of C. mollis is more posterior, inserted between neural spines 5 and 6 (vs. between 3 and 4 in C. orri ). The counts of pyloric caeca and coloration of stomach also distinguish C. mollis (8 and pale, respectively) from C. orri sp. nov. (at least 15 to 21 and dark) ( Burke 1930; this study). Careproctus longidigitus Kai & Matsuzaki, 2019 and Careproctus staufferi Orr, 2016 also share the following characters with the present new species: trilobed teeth, a cephalic pore pattern of 2-6-7-2, chin pores in a single pit, and a pectoral fin with a notch ( Orr 2016; Kai & Matsuzaki 2019; this study). However, the new species is clearly distinguishable from C. longidigitus in having 34–35 pectoral-fin rays (vs. 28–32) and rays in lower lobe of pectoral fin connected with membrane (vs. filamentous and nearly completely free of membrane) and from C. staufferi in having 58–60 total vertebrae (vs. 44–46), 52–53 dorsal- (vs. 40–42), and 47–49 anal-fin rays (vs. 33–37) ( Orr 2016; Kai & Matsuzaki 2019; this study).

Figures

FIGURE 1. Careproctus cyanogladius sp. nov., BSKU 96466, holotype, 303.6 mm SL, in preserved condition (A), in fresh condition (B); Careproctus orri sp. nov., NSMT-P 53657, holotype, 121.0 mm SL, in preserved condition (C); Careproctus brevipectoralis, BSKU 96445, 194.6 mm SL, in preserved condition (D), in fresh condition (E).

FIGURE 2. Teeth on upper jaw (A–C, bar 0.5 mm) and pectoral girdle (D–F, bar 5 mm) in three species of Careproctus. A: Careproctus cyanogladius sp. nov., BSKU 96466, holotype, 303.6 mm SL; B: Careproctus orri sp. nov., NSMT-P 53657, holotype, 121.0 mm SL; C: Careproctus brevipectoralis, BSKU 96445, 194.6 mm SL; D: C. cyanogladius sp. nov., BSKU 96458, paratype, 161.9 mm SL; E: C. orri sp. nov., HUMZ 201730, paratype, 143.4 mm SL; F: C. brevipectoralis, BSKU 96445.

FIGURE 3. Ventral view of head.A: Careproctus cyanogladius sp. nov., BSKU 96466, holotype, 303.6 mm SL; B: Careproctus orri sp. nov., NSMT-P 53657, holotype, 121.0 mm SL; C: Careproctus brevipectoralis, BSKU 96445, 194.6 mm SL. Red arrows: anteriormost maxillary pores.