Holotype

MIMB 2382: female, 340 mm SL, bank east of Krusenstern Strait, Kuril Islands, 47°50′N, 154°25′E, commercial trawl, 550 m, 1 October 1996, Seitoku Maru, tr. 93, L. A. Borets.

Paratypes

MIMB 2380: male, 287 mm SL, off Lovushki Rocks, 48°27′N, 153°52′E, bottom trawl, 368 m, 9 July 1993, Akademik Oparin, tr. 11. MIMB 2381: female, 283 mm SL, off Lovushki Rocks, 48°26′N, 153°52′E, bottom trawl, 190 m, 9 July 1993, Akademik Oparin, tr. 13. Same general locality as holotype, all from vessel Tomi Maru 53 by commercial trawl: MIMB 3171: male, 270 mm SL, 47°49′N, 154°26′E, 644–700 m, 14 September 1997, tr. 87. MIMB 3172: female, 307 mm SL, 47°56′N, 154°31′E, 403–400 m, 15 September 1997, tr. 94. NSMT P-57330: 5 males, 243–309 mm SL and 1 female, 261 mm SL, 47°55′N, 154°30′E, 380–413 m, 10 December 1998, tr. 95. MIMB 3173: female, 335 mm SL, same collection as preceding. NSMT P-57331: male, 270 mm SL, 47°55′N, 154°30′E; 426–443 m, 11 December 1998, tr. 96. MIMB 3019: 4 males, 238–313 mm SL and 5 females, 268–326 mm SL, 47°56′N, 154°31′E, 400–408 m, 11 December 1998, tr. 97. NSMT P-57332: female, 281.5 mm SL, 47°55′N, 154°31′E, 426–445 m, tr. 98. MIMB 3020: male, 251 mm SL and 2 females, 255–325 mm, 47°57′N, 154°30′E, 370–440 m, 11 December 1998, tr. 99. MIMB 3021: 2 males, 300–321 mm SL and 5 females, 221–330 mm SL, 47°56′N, 154°30′E, 400–430 m, 12 December 1998, tr. 100. HUMZ 161930–161936: 4 males, 222–304 mm SL and 3 females, 291–305 mm SL, 47°50′N, 154°26′E–47°56′N, 154°34′E, 376–685 m, 12 December 1998, tr. 101. MIMB 3022: male, 295 mm SL, 48°05′N, 154°25′E, 201–220 m, 31 December 1998, tr. 139. MIMB 3023: male, 248 mm SL, 47°55′N, 154°30′E, 441–488 m, 31 December 1998, tr. 142.

Diagnosis

A species of Lycenchelys as defined by Anderson (1994), distinguished from all congeners with the following combination of characters: pelvic fins and pyloric caeca absent; vertebrae 28–31 + 103–110; dorsal fin origin associated with vertebrae 2–3; postorbital pores five (rarely four or six); occipital and interorbital pores present; pseudobranch filaments 5–10; vomerine and palatine teeth present; lateral line ventral, complete.

Counts and measurements

Values for holotype first, followed by range of paratypes in parentheses: vertebrae 30 + 107 = 137 (28–31 + 103–110 = 132–139); D 132 (128–134); A 111 (107–115); C 10 (9–11); P 16 (13–17); pelvics absent; vomerine teeth 10 (4–13); palatine teeth 14/14 (8–18/7–16); gill rakers 3 + 12 = 15 (2–3 + 8–12 = 10–15); branchiostegal rays 6 (6); pseudobranch filaments 7 (5–10). Following measurements in percent SL: head length 13.3 (12.2–15.9); head width 6.3 (4.6–6.8); head depth 5.9 (5.1–6.5); pectoral fin length 6.7 (5.5–7.0); predorsal length 13.7 (12.4–15.2); preanal length 30.9 (28.7–33.7); body height 6.1 (4.9–7.2); gill slit length 5.0 (3.8–5.6). Following measurements in percent HL: head width 47.5 (32.7–49.2); head depth 44.4 (37.6–46.5); upper jaw length 41.0 (33.5–45.5); pectoral fin length 50.1 (39.0–51.3); snout length 25.9 (24.9–30.0); eye diameter 16.2 (14.0–18.3); gill slit length 37.5 (28.7–36.5); interorbital width 6.7 (4.1–6.8); interpupillary width 23.3 (14.9–22.6); caudal fin length 15.5 (12.4–18.2). Pectoral base/length ratio: 46.0 (38.3–50.8).

Description

Based on 14 males and 16 females, all adults or subadults, the largest, a 340-mm SL female (holotype), the smallest a 221-mm SL female. Head elongate, ovoid, dorsoventrally depressed; nape almost flat; snout tip steeply sloping. No sexual dimorphism exhibited in head lengths or widths, as in some congeners. Scales absent on head and nape (rarely present on nape in sparse, scattered pattern), extending anteriorly to just below dorsal fin origin; scales absent on pectoral fin and base, in pectoral axil and ventral surface of abdomen. Scales present on dorsal and anal fins to about half their height (or more in largest specimens). Eye slightly ovoid in smallest specimens, more rounded in largest, entering dorsal profile only in largest. Gill slit extending ventrally to opposite ventralmost pectoral ray or slightly above it. Opercular flap at upper end of gill slit well developed, rounded; slit extending forward about one eye diameter. Pectoral fin origin well below body midline, insertion on abdomen; posterior margin of fin wedge-shaped; lowermost 5–6 rays thickened and slightly exserted, definition better in smallest specimens. No ventral abdominal plica (fold).

Mouth subterminal, upper jaw extending to middle of eye or slightly beyond. Males with longer upper jaws than females: upper jaw 36.9–45.8% HL, x̄ = 40.8, SD = 2.87 in 13 males 251–321 mm SL; upper jaw 33.5–41.0% HL, x̄ = 35.9, SD = 2.26 in 14 females 252–340 mm SL. Nostril tube not reaching upper lip when pressed forward. Lips thin, no lower lip lobe. Oral valve not reaching anterior edge of vomer. Jaw teeth small, retrorse, in single row in both jaws posteriorly, these more widely spaced in males than in females. Females with more numerous and generally smaller teeth than males: male dentary teeth 15–26, x̄ = 20.9, SD = 3.48 in same sample as jaw lengths above; females with 26–36 dentary teeth, x̄ = 28.8, SD = 2.94. Numbers of premaxillary teeth statistically insignificant between the sexes. Vomerine teeth in a patch, increasing in number with growth; palatine teeth in a single row.

Cephalic lateralis system with usually five postorbital pores arising from frontal-lateral extrascapular commissure; variation is of two specimens with a pore (number 2 in both) absent on one side, five on the other, and two with an extra (sixth) pore on one side, five on the other. Two pairs of anterior supraorbital (nasal) pores, one set anteromesial to nostril tube, the other posteriorly. Usually eight suborbital pores, six arising from ventral ramus of bone chain under eye and two from ascending ramus behind eye (formula 6 + 2); variation great in suborbitals, as is typical in zoarcids: six specimens with pattern 6 + 2/6 + 3, two with pattern 6 + 2/6 + 1 and one with pattern 6 + 3/6 + 3. Eight preoperculomandibular pores, four arising from dentary, one from anguloarticular and three from preopercle. Interorbital pore single, present in all, set on line through anterior margins of eyes. Occipital pores usually three, a median one set posteromesial to two laterals; two specimens with anomalous fourth pores set off main channel of occipital commissure, one posteriorly, the other right laterally. Body laterally line ventral, complete to tail tip, steeply bowed under pectoral fin.

Dorsal fin origin above pectoral base or anterior quarter of pectoral fin, associated with vertebrae 2–3, with no free supraneurals. First dorsal pterygiophore bearing usually one ray, less often two. Anal fin origin associated with fourth-to-last precaudal to ultimate precaudal vertebrae, with 4–9 ray-bearing pterygiophores inserted anterior to haemal spine of first caudal vertebra. First anal pterygiophore bearing almost equally one or two rays; last anal ray associated with second preural vertebra. Caudal fin with 1–3, usually two, epural, 4–5, usually four, upper hypural and 4–5, usually four, lower hypural rays.

Gillrakers short, roughly triangular, outermost on upper limb and dorsalmost on lower limb bifurcating at tips in larger specimens; lower rakers longer and more slender in largest fish. Pseudobranch filaments long, generally more numerous than in deeper-living congeners (usually 6–8). Pyloric caeca undeveloped.

Coloration

Two color morphs exist in L. fedorovi, unrelated to sex or size. Uniformly pigmented specimens are solid black without any patterning. Variegated specimens (Fig. 1) have dark brown to black mottling dorsally, the markings becoming more spotlike posteriorly, especially in smaller specimens. The heads and pectoral fins of variegated specimens are brown; ventral surface of abdomen gray, median area of body and ventral area of tail light brown. Whitish blotch on dorsal part of caudal region in both morphs, with markings in larger specimens (white area absent in one fish). Eye dark blue.

Distribution

Distributional data from the type series and other specimens not available to us indicate that L. fedorovi may have an exceedingly restricted range relative to congeners. The species became known only in 1993 after decades of commercial and scientific trawling on the Pacific side of the Kuril Islands and southeastern Kamchatka (Orlov, 1998). So far it is known only from a rise complex stretching from east of Krusenstern Strait to the outer shelf just southeast of Onekotan Island in depths of 190–700 m. Because the frequency of occurrence increases with depth (Table 1), it is reasonable to assume that the species ranges deeper than 800 m. However, lowest preferred temperature appears to be approached above 600 m. Specimens were caught at near-bottom temperatures of 1.70–4.15 C. Temperatures from 2.5–3.5 C seem most optimal, 78% of all specimens were taken in this range, which corresponds to depths of about 450–550 m (Table 1).

Table 1. Frequency Distribution of Lycenchelys fedorovi by Depth of Capture (n = 171) and Near Bottom Temperature (n = 141)

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High-relief rocky sea floor, steep trench gradients, and strong near-bottom currents around the northern and central Kuril Islands has produced favorable conditions for the development of a benthic community dominated by sponges, hydrozoans, and anthozoans (Udintsev, 1955; Kuznetsov, 1959). Our data on distribution and feeding (below) for L. fedorovi in this community parallels that for another fish, the cottid Thyriscus anoplus (Tokranov, 1998). Thus, habitat specificity and substrate fidelity in L. fedorovi and T. anoplus may explain why these species have not been encountered north of Fourth Kuril Strait and off southeastern Kamchatka (Orlov, 1998), where the main bottom type is sand-gravel (Bezrukov and Murdmaa, 1959), dominated by ophiuroids, infaunal polychaetes, and bivalves (Kuznetsov, 1959).

Etymology

Named in honor of our friend and colleague Vladimir Vladimirovich Fedorov, Zoological Institute, St. Petersburg, Russia, in recognition of his numerous contributions to the ichthyology of the North Pacific.

Food habits

Species of Lycenchelys are benthic infaunal and epifaunal predators. Diets have been reported infrequently and, depending on locality, rely chiefly on bivalves, crustaceans, gastropods, and, to a lesser extent, polychaetes and ophiuroids (Andriashev, 1954; Wenner, 1978; Anderson, 1995). Dominant crustacean taxa include ostracods, cumaceans, amphipods, and isopods.

Stomachs and anterior intestines of 25 specimens of L. fedorovi contained chiefly gammaridean and caprellidean amphipods, with polychaetes, isopods, and an ostracod of minor importance (Table 2). Important prey reported for other specis of Lycenchelys in other localities (cited above) were absent or unimportant, such as cumaceans, scaphopods, gastropods, bivalves, and ophiuroids. Prey lengths were generally small compared to mouth size, with 67% of total items 2–10 mm in length, 28% 10–20 mm and 5% 20–50 mm.

Table 2. Food Items of Lycenchelys fedorovi by Frequency and Weight Percentages

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Reproduction

During December 1998, all L. fedorovi females examined (252–335 mm SL) contained ova in early stages of development. These eggs were whitish, irregular in shape, with diameters up to 1.0 mm. Flattened residual eggs were found in the ovary of one female. Their in vivo size was estimated at 3–4 mm in diameter, similar to that reported for ripe eggs in other species of Lycenchelys (Anderson, 1995). The opened ovipores of several December females were observed; none in July samples. One female, 312 mm SL, collected in July 1999 contained 60–70 yellowish eggs, 1.5–2.1 mm in diameter; three others contained undeveloped eggs up to 1.0 mm.

Yao and Crim (1995a,b) reported that the ovipore of another zoarcid, Zoarces americanus (as Macrozoarces), opened 16–22 h prior to oviposition, which occurred 6–17 h after copulation. This suggests that many of the December L. fedorovi females were in a postspawning condition because some mature residual eggs were found in this winter sample and normal, developing eggs were found in summer. A possible late summer and autumn spawning season is thus suggested for L. fedorovi.

Comparisons

Andriashev (1955) grouped North Pacific species of Lycenchelys into shallow-dwelling “bathyal” and deeper-living “abyssal” forms, a step mostly corroborated worldwide by Anderson (1982, 1988, 1995). The bathyal (upper slope) forms are characterized by having large eyes, usually fewer than 25 precaudal vertebrae, occipital and interorbital pores present, 3–4 postorbital pores, and are often colored (reddish) or have variegated pigment patterns on bodies and fins. The bathyal L. fedorovi generally fits the above characterization with one notable exception, its high precaudal vertebral count (28–31). This character and others, such as head pore patterns, pigmentation, and counts, ally it with L. maculatus Toyoshima, 1985, described from off northern Honshu, Japan. It differs from L. maculatus in its lack of pelvic fins and predorsal scales, usually five postorbital pores, and its whitish tail tip. We believe that Toyoshima's (1985) comparison of L. maculatus with another pigmented congener, the western Arctic L. kolthoffi as an “ally,” is typological, in that L. kolthoffi is probably more closely related to another western, pigmented, bathyal eelpout, L. sarsi (MEA, unpubl.). Both western forms differ from L. fedorovi and L. maculatus in their fewer vertebrae and more posterior dorsal fin origins. Thus, phylogenetic analysis of this large genus will have to rely on more than a few meristics, morphometrics, and external characters to sort out natural subsets of taxa than prescribed previously.