Epinnula pacifica, Ho & Motomura & Hata & Jiang, 2017

Ho, Hsuan-Ching, Motomura, Hiroyuki, Hata, Harutaka & Jiang, Wei-Chuan, 2017, Review of the fish genus Epinnula Poey (Perciformes: Gempylidae), with description of a new species from the Pacific Ocean, Zootaxa 4363 (3), pp. 393-408 : 401-405

Epinnula pacifica sp. nov.

Figures 1C–D , 2B–C , 3 , 4A–D ; Tables 2–4 New English name: Pacific Domine

Epinnula magistralis (not of Poey): Kamohara, 1938a:48, pl. 3, fig. 3; 1938b: 20; 1940: 93, fig. 43. Matsubara & Iwai, 1952:198.? Parin & Kotlyar, 1991:1004.? Nakamura & Parin, 1993:26. Mundy, 2005:499. Ho & Yee, 2012:62. Stewart, 2015:1605. Hata & Motomura, 2016:11.

Holotype. KAUM-I.72 269, 710 mm SL, off Taira Island , Tokara Islands, Kagoshima Prefecture, Japan, long line, purchased from market, 4.7 kilograms when fresh, 27 Apr. 2015, coll. H. Hata.

Paratypes. BPBM 25938 , 334 mm SL, assumed from Hawaiian Islands (gift from Hawaii Institute of Marine Biology), no other data . BPBM 28876 , 425 mm SL, Hawaiian Islands (gift from Maeda fish market, collected by vessel Shirley Y), 12–13 Feb. 1983 . BPBM 30623 , 477 mm SL, Lanai side, Penguin Bank , off Molokai, Hawaiian Islands, 283 m, hook and line, 3 Feb, 1995, coll. R. Yamashiroya . BSKU 4409 , 312 mm SL, Mimase fish market, Kochi City, 26 Dec. 1954 . FRIP 21307 , 326 mm SL, Cheng-gong , Taitung, SE Taiwan, bottom gill net, 18 Aug. 2005 . KAUM –I. 51544, 750 mm SL, off Yoron Island , Amami Islands, Kagoshima Prefecture, Japan, line fishing, 29 Oct. 2012 (half dissected) . NMMB-P 16629 , 335 mm SL, Nan-fang-ao, NE Taiwan, ca. 300 m, 11 Mar. 2011, coll. H.-C. Ho . NSMT-P 62524 , 219 mm, Odawara, Kanagawa Prefecture, Honshu, Japan.

Diagnosis. A species of Epinnula differing from its only congener in having dorsal-fin XV–XVI, I, 17–18; anal-fin III, 15–16; longest second dorsal-fin ray 2.3–2.9 in HL; pectoral fin long, 1.5–1.8 in HL; pelvic fin short, 1.4–3.2 in HL; origin of anal fin behind that of second dorsal fin; scales on upper lateral-line 185–208, on vertical part of lower lateral line 66–81, on horizontal part of lower lateral line 172–199.

Description. Morphometric and meristic data of the type series are provided in Tables 2–4, respectively. The following data are provided for the holotype, followed by range of all types, except where indicated.

Dorsal fin XVI, I, 18 (2 paratypes with XV, I, 18, 1 with XVI, I, 17); anal fin III, 16; pectoral fin 15 (1 paratype with one side and 1 with both sides 16); pelvic fin I, 5; branchiostegal rays 7; vertebrae 16+16=32. Scales on upper lateral line 207 (right side) or 208 (left side) (185–202 in paratypes); scales on vertical part of lower lateral line 69 (66–81); scales on horizontal part of lower lateral line 196 or 199 (172–197); pyloric caeca 11 (7–11, n=3).

Body rather deep and strongly compressed, body depth at pelvic fin base 4.0 (3.7–4.4) times in SL, body width at pelvic-fin base 9.7 (8.5–10.5, 15.2 in 212 mm specimen) in SL. Head moderately large, head length 3.2 (3.1–3.3) in SL. Dorsal profile of head slightly elevated before anterior nostril, then nearly straight to origin of dorsal fin. Snout bluntly conical Mouth terminal and large, lower jaw slightly projecting beyond tip of upper jaw; maxillary extends to slightly anterior to a vertical of midpoint of eye.

Eye large and round, its diameter 4.8 (4.3 in 750 mm specimen, 3.3–4.0 in others) times in HL; interorbital slightly concaved, with 2 or 4 low longitudinal ridges on each frontal; less bony space width 5.2 (5.4 in 750 mm specimen, 5.3–6.6 in others) in HL, less fleshy width 4.3 (3.6–4.6) in HL. Snout length 1.8 (1.1–1.8) times of eye diameter (1.5–1.8 in two largest specimens, 1.1–1.4 in others). Two nostrils, both at about level of middle of eye; anterior nostril rounded, directed forward; posterior nostril a vertical slit.

Anterior portion of upper jaw with 2 (2–4) large fixed and 2 (1–3) large depressible fang (some are missing or with small regenerating ones); upper jaw with 20 (15–25) blade-like teeth, widely spaced, alternating fixed and depressible ones; lower jaw with a pair of canine-like teeth at front, entirely exposed when mouth closed; lower jaw with single row of 9 (7–9) widely-spaced, blade-like teeth, the first one smallest, gradually larger posteriorly; vomer toothless; single row of 13 (up to 15) small compressed teeth on palatines.

Angle of preopercle armed with 2 small but rather pungent spines; lower margin of preopercle with 2 weak triangular spines; opercle strengthened by 2 obscure ridges, not ending in spines.

Lateral-line origin above upper end of gill opening, running backward to point of bifurcation beneath the fifth dorsal-fin spine (slightly behind in some paratypes); upper lateral line running directly posteriorly about parallel to dorsal contour of body to base of middle caudal-fin rays; lower lateral line running nearly vertically down behind middle of pectoral-fin base, then downward and slightly backward to above origin of pelvic fin, and finally along lower contour of body to base of caudal fin (that of 477 mm specimen runs to caudal peduncle and joins the upper branch).

Head and body mostly covered by small imbricated scales, except for lips (premaxillae), lower jaw, anterior half of snout and maxillary and branchiostegal membranes, which are scaleless. Small scales on inter-radial membranes run to about 1/3 the height above the base of each fin.

Base of spinous part of dorsal fin 2.3 (2.1–2.4) times of soft part; base of soft dorsal fin about as long as that of anal fin and preceded by a weak spine; anal fin opposite soft dorsal, with 3 spines, the first inserted vertically below first soft dorsal-fin ray; margins of soft dorsal and anal fins shallowly but widely concave.

Pectoral fin rather short, 1.6 (1.5–1.8) in HL, extending to below membrane of eighth and ninth dorsal-fin spines. Pelvic fin inserts below middle of pectoral fin, extending to anterior fourth of distance between its origin to the origin of anal fin in two largest specimens, to midway of the distance in other most paratypes, beyond midway in 219 mm specimen; almost to the anus in a 188 mm SL specimen reported in Matsubara & Iwai (1952, specimen not examined); pelvic-fin spine shorter than the fin, broken in the holotype (5.3 in 750 mm specimen; 2.1–2.2 in two smallest specimens, 2.8–4.1 in other specimens) in HL. Caudal deeply forked, upper lobe of caudal fin 1.3 (1.1–1.4) in HL.

Gill rakers small, mostly embedded under the skin, forming many broad, roundish, plates, each armed with 3 or 4 sharp cusps distally and few spines on the surface; 1 or 2 small rakers, armed with small spines alternating those larger rakers; raker at angle of first gill arch T-shaped, with about one third of its entire length exposed; its inner surface not armed with minute spines.

Coloration. When fresh, body uniformly deep grayish with lateral sides silver white; all fins darker ( Figs. 1C– D , 2B , 4D ). Preserved coloration uniformly dark grayish or brownish, with fins slightly darker ( Figs. 4B–C ).

Etymology. The specific name pacifica is derived from the main distribution of the species, the Pacific Ocean.

Distribution. This species is represented by the type series collected from Hawaii, Japan and Taiwan. Also reported from New Zealand ( Stewart, 2015). The holotype was collected by long line from unknown depth, one Hawaiian specimen was collected by hook and line at 283 m, and one specimen was collected by bottom trawl around 300 m.

Remarks. Kamohara (1938) first reported two specimens of E. magistralis collected from Japan, Matsubara & Iwai (1952) reported a third specimen collected from Japan, Ho & Yee (2012) reported one specimen from Taiwan, Hata & Motomura (2016) reported two large specimens from southern Japan, and Stewart (2015) reported specimen from New Zealand. All these records are recognized as representing the new species. One fish collected from Hawaii by an angler ( Fig. 4D , specimen not retained) shows characters similar to E. pacifica sp. nov. and is thus considered as that species.

The teeth on jaws and palatines vary in number, which may be a result of damage or stage of tooth regeneration. There is a mixture of fixed and depressible teeth. BPBM 25938 has 6 well-developed fangs, 3 fixed and 3 depressed, at anterior portion of upper jaws, whereas others have 1–3 of each kind of teeth, except for NSMT-P62524 that has 4 fixed and 1 depressible teeth. Some specimens have relatively small fangs which may be attributed to tooth regeneration.

It is likely that the species typically has 6 fangs, either fixed or depressible, at the front of the roof of the mouth. Upper jaw with single row of alternating fixed and depressible teeth. Although the numbers of teeth vary, the total number of teeth is about 23–25 in all specimens (including the missing teeth usually seen as a hole). There are 2 larger, fixed fangs at front of lower jaw of all specimens. Lower jaw with a single row of 7–8 (typically 8) fixed, widely-spaced, blade-like teeth, the first one smallest, gradually increasing in size posteriorly. There is single row of 6–15 small, blade-like teeth on each palatine. The number of teeth on jaws and palatines does not show any trend with growth, and they seem to be easily lost and regrown.

BSKU 4409 NSMT- TFRI 21307 BPBM 25938 NMMB- BPBM 28876 BPBM 30623 KAUM- KAUM-

P62524 P16629 I72269* I51544

Standard length (mm) 212 219 326 334 335 425 477 710 750

%SL Mean BSKU 4409 NSMT- TFRI 21307 BPBM 25938 NMMB- BPBM 28876 BPBM 30623 KAUM- KSUM-

P62524 P16629 I72269* I51544

Standard length (mm) 212 219 326 334 335 425 477 710 750

%HL Mean

Figures

FIGURE 2. Lateral view of head. A. Epinnula magistralis, neotype, USNM 391434, 820 mm SL B. E. pacifica sp. nov., holotype, KAUM-I.72269, 710 mm SL. C. E. pacificasp. nov., paratype, BPBM 25938, 334 mm SL. Not to scale.

FIGURE 3. Distribution map of known records of Epinnula magistralis (open dots) and Epinnula pacifica sp. nov. (solid dots). One dot may represent more than one record. Question mark meansunidentified record (juvenile).

FIGURE 4. Epinnula pacifica sp. nov. A. Paratype, NMMB-P16629, 335 mm SL, fresh. B. Paratype, BPBM 25938, 334 mm SL, preserved. C. Paratype, NSMT-P62524, 219 mm, preserved. D. Fresh caught individual, from Hawaii, specimen not retained, photo bySteve Wozniak.

FIGURE1. A.Epinnulamagistralis, neotype, USNM391434,820 mm SL,preserved.B. Epinnula magistralis,USNM 37238, 426 mm SL, non-type, preserved. C. Epinnula pacifica sp. nov., holotype, KAUM-I. 72269, 710 mm SL, fresh. D. Epinnula pacifica sp. nov., paratype, KAUM-I.51544, 750 mm SL, fresh. Not to scale.