Careproctus lycopersicus Orr, 2012

Kai, Yoshiaki, Matsuzaki, Koji & Mori, Toshiaki, 2019, First Records of the Snailfish Careproctus lycopersicus (Cottoidei: Liparidae) from the Western North Pacific, Species Diversity 24, pp. 115-118 : 115-118

Careproctus lycopersicus Orr, 2012

[New standard Japanese name: Tomato-kon’nyaku-uo] ( Figs 1 , 2 ; Table 1)

Careproctus lycopersicus Orr, 2012: 257 , figs 1A, 2A (original description, type locality: 56.0153°N, 168.8771°W, Bering Sea, 1096 m depth).

Materials examined. FAKU 145976, 168.6 mm SL, male, off Rausu , Menashi, Hokkaido, Japan, 500–750 m depth, 5 September 2017, F/ V Houyu-Maru . FAKU 145977, 176.3 mm SL, male, off Rausu , Menashi, Hokkaido, Japan . FAKU 146592, 204.4 mm SL, male, 44.313°N, 145.416°E, off Rausu , Menashi, Hokkaido, Japan, 800–1000 m depth, 14 May 2018, F/ V Houyu-Maru . FAKU 146593, 182.4 mm SL, female, 44.062°N, 145.364°E, off Rausu , Menashi, Hokkaido, Japan, 570–825 m depth, 25 August 2018, F/ V Houyu-Maru .

Diagnosis. Careproctus lycopersicus is distinguished from all other species of Careproctus by the following combination of characters: vertebrae 45–50; dorsal-fin rays 42–45; anal-fin rays 34–38; pectoral fin deeply notched with 33–38 rays; large pelvic disk> 29.9% HL (> 9.0% SL); teeth strongly trilobed on both jaws, inner teeth weakly trilobed or shouldered; cephalic pore pattern 2-6-7-1, chin pores paired; gill slit extending ventrally to pectoral rays 4–12; body bright red in life.

Description of Sea of Okhotsk specimens. Measurements are given in Table 1. Body robust, tapering posteriorly, rounded in cross section anterior to anus, deepest at nape. Skin relatively thick; prickles absent. Head robust and large, dorsal profile strongly sloping from nape to snout. Snout blunt, slightly protruding beyond tip of upper jaw. Mouth terminal and large; maxilla extending to mid orbit or to posterior margin of orbit; oral cleft extending to anterior margin of orbit. Premaxillary teeth strongly trilobed in 8–10 oblique rows forming broad bands; inner teeth becoming larger, weakly trilobed or shouldered. Mandibular teeth trilobed in 8 oblique rows; inner lycopersicus .

teeth becoming larger, weakly trilobed or shouldered ( Fig. 2A ). Diastema absent at symphysis of upper and lower jaws. Orbit round, relatively small. Nostril single, with short tube at level with middle of orbit. Pores of cephalic lateralis of moderate size: nasal pores 2, maxillary pores 6, preoperculomandibular pores 7, suprabranchial pores 1; cephalic pore pattern 2-6-7- 1. Chin pores paired in separate pits. Interorbital pore absent. Gill slit large, upper margin well above level of dorsal margin of orbit, extending ventrally to pectoral rays 4–12. Opercular flap angular or rounded, pointing posterodorsally.

Vertebrae 47–48, precaudal 12 and caudal 35–36. Dorsalfin unlobed, rays 42–44, tip of rays slightly exserted. Anteriormost dorsal-fin pterygiophore inserted between neural spines 3 and 4, bearing single short ray. Membrane of posterior dorsal-fin rays continuous with caudal fin. Anal-fin rays 35–36. Anal-fin origin below vertebrae 14. Membrane of posterior anal-fin rays continuous with caudal fin. Caudal fin slightly rounded. Principal caudal-fin rays 10; dorsal procurrent rays 2, ventral procurrent ray 1. Hypurals and parhypural fused into single plate. Pleural ribs 2 pairs, on abdominal vertebrae 9–10 or 10–11.

Pectoral fin deeply notched, with 34–38 rays, just reaching or not reaching to level of anal-fin origin; upper lobe with 27–28 rays; lower lobe moderately elongate with 9–10 rays, 6th ray from ventral side longest, just reaching to anus. Tip of pectoral-fin rays free of membrane, lower rays more strongly exserted. Uppermost pectoral-fin base level with region between ventral margin of orbit and cleft. Lowermost pectoral-fin base posteriorly below posterior margin of orbit. Proximal pectoral radials 4 (3+1) ( Fig. 2B ). Upper and lower part of radials 1 and 2 deeply notched; upper part of radial 3 deeply notched, crescent shaped; radial 4 rounded. Interradial fenestrae 3, blunt triangular shaped, extending between scapula and proximal radials 1–3. Scapula broadly Y-shaped with strong helve, extending closely to uppermost proximal radial. Coracoid with broad triangular head and long thin helve. Pelvic disk large, round; length (31.3–37.4% HL) slightly longer than wide (30.0–34.1% HL). Anus posterior to gill slit, slightly closer to pelvic disk than to anal-fin origin. Pyloric caeca 12–17.

Coloration ( Fig. 1 ). In life, head, body, and fins uniform bright red; distal margins of posterior dorsal, anal, and pectoral fins faintly dark in males. In preservation, head and body pale; distal margins of posterior dorsal, anal, and pectoral fins faintly dark in males; stomach and peritoneum pale or dusky.

Distribution. Known from the Bering Sea, eastern Aleutian Islands, and southern Sea of Okhotsk (Nemuro Strait) at depth of 304–1096 m ( Orr 2012; this study).

Remarks. The present specimens from the southern Sea of Okhotsk were identified as Careproctus lycopersicus on the basis of having a deeply notched pectoral fin with 34–38 rays, a large pelvic disk> 31.3% HL (> 9.7% SL), strongly trilobed teeth on both jaws, a cephalic pore pattern of 2-6-7-1, paired chin pores, and a large gill slit ( Orr 2012). The shape of the pectoral-fin girdle and most of the measurements are also similar between the specimens from the Sea of Okhotsk and the type specimens, however, the ventral margin of gill slit (extending ventrally to pectoral-fin ray 4–11 in the former vs. 8–12 in the latter) is slightly different ( Table 1; Orr 2012). In addition, the type specimens of C. lycopersicus have strongly trilobed teeth in 9–20 oblique rows forming the broad bands and have 8–13 pyloric caeca ( Orr 2012; this study), but the present specimens have strongly trilobed teeth in 8–10 oblique rows, inner teeth becoming larger, weakly trilobed or shouldered ( Fig. 2B ) and have 12–17 pyloric caeca. The previously known maximum size of the species is 142.6 mm SL (UW 119817), but the present specimens were much larger, 168.6–204.4 mm SL. We herein considered the above continuous differences between the specimens from the Sea of Okhotsk and the type specimens are attributed to intraspecific variations, however, further study, including genetics, may demonstrate that they represent two different species.

Among the species of Careproctus known from the western North Pacific, Careproctus sinensis Gilbert and Burke, 1912 and Careproctus zachirus Kido, 1985 are similar to C. lycopersicus in having a cephalic pore pattern of 2-6-7-1 ( Kido 1985, 1988; Matsuzaki et al. 2017; this study). However, C. lycopersicus is clearly distinguishable from both species in having a gill slit extending ventrally to pectoral rays 4–12 (vs. entirely above the pectoral fin). The cephalic pore pattern of Careproctus surugaensis Murasaki, Takami and Fukui, 2017 , known only from the holotype collected from Suruga Bay, Japan, is unknown because of the poor condition of the holotype ( Murasaki et al. 2017). The counts of dorsal-, anal-, and pectoralfin rays of C. surugaensis are similar to those of C. lycopersicus (47, 39, and 32 vs. 42–47, 33–38, and 33–38), but the pelvic disk length and body depth at pelvic disk of the former (7.9% SL and 16.6% SL) is somewhat smaller than the latter (9.7– 11.9% SL and 24.8–30.3%) ( Table 1; Murasaki et al. 2017). The former is further distinguishable from the latter in having a light orange body (vs. a bright red body).

A new standard Japanese name, Tomato-kon’nyaku-uo, is proposed here for C. lycopersicus , “tomato” being Japanese for “tomato plant (= Solanum lycopersicum Linnaeus, 1753 )” applied for its scientific name ( Orr 2012). “Kon’nyaku-uo” refers to the species of Careproctus in Japanese.

Comparative materials. Careproctus lycopersicus: UW 119816, paratype, 113.5 mm SL, 52.650°N, 172.24°W, 397 m depth, 26 June 1997, F/V Dominator; UW 119817, paratype, 142.6 mm SL, 60.264°N, 179.168°W, 877 m depth, 12 July 2000, F/V Morning Star. Careproctus sinensis: USNM 73339, holotype, 57.9 mm SL, 38.583°N, 138.683°E, 366 m depth, 18 July 1906, R / V Albatross . Careproctus zachirus: HUMZ 88338, holotype, 252.0 mm SL, 51.585°N, 179.360°W, 300– 350 m depth, 7 July 1980; FAKU 120206 , 206.0 mm SL, 53.300°N, 170.750°E, 131 m depth, 4 October 1980 .

Figures

Fig. 1. Careproctus lycopersicus from the Nemuro Strait, Hokkaido, Japan (A: FAKU 146593, 182.4mm SL, fresh condition; B: FAKU 145976, 168.6mm SL, preserved condition) and one of the paratypes from the Bering Sea (C: UW 119816, 113.5mm SL, preserved condition).

Fig. 2. Mandibular teeth (A) and right pectoral girdle (B) of Careproctus lycopersicus (FAKU 145977, 176.3mm SL). Scale bars 1mm (A) and 5mm (B).