Epinnula magistralis Poey, 1854

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 : 395-401

Epinnula magistralis Poey, 1854

Common name: Domine

Figures 1A–B , 2A , 3 ; Tables 1–2

Epinnula magistralis Poey, 1854:369 , pl. 32, figs. 3–4 (original locality: Havana, Cuba). Günther, 1860:349; Goode & Bean, 1896:198, pl. 57, fig. 211; Jordan & Evermann, 1896:880. Parin & Nakamura, 2003:1817 (in part).

Neotype (herein designated). USNM 391434 (820 mm SL), 25°56.814'N, 79°18'W, north of Bimini, Bahamas, western Atlantic Ocean , hook and line, 472–488 m, coll. R. Schatman, 18 Dec. 1995.

Non-types. USNM 37238 (1, 426 mm SL), Caribbean Sea , western Atlantic Ocean , 1885, coll. United States Fish Commission. UF 34950 (1, 348 mm SL), Virgin Island , 8 miles south of St. Thomas , Caribbean Sea, western Atlantic Ocean, 176 m, 26 Oct. 1981 , coll. R. Heagey. UF 233577 (1, 147.5 mm SL), sta. 2457, 23°34.5'N, 79°07'W, Great Bahama Bank , southwest of Andros Island, Bahamas, western Atlantic Ocean, 457.2 m, 40-ft trawl, coll. M/ V Silver Bay, 5 Nov. 1960 .

Diagnosis. A species of Epinnula differing from the only congener in having dorsal-fin XV–XVI, I, 15–16; anal-fin III, 13–14; snout long, length 2.5–3.0 in HL; eye small, diameter 4.1–4.5 in HL; dorsal fin low, first dorsalfin spine 3.4–5.8 in HL, longest second dorsal-fin ray 3.0– 3.5 in HL; pectoral fin short, 2.0– 2.1 in HL; pelvic fin short, 3.7–4.7 in HL; origin of anal fin behind that of second dorsal fin; scales on upper lateral-line 196–227, on vertical part of lower lateral line 83–98, on horizontal part of lower lateral line 201–237.

Description. Morphometric and meristic data are given in Tables 1 and 2, respectively. Data below are provided for the neotype, followed by range for the three other specimens, except where indicated.

Dorsal-fin XV, I, 16 (XVI, I, 16 in 147.5 mm specimen; XVI, I, 16 in 348 mm specimen; XV, I, 15 in 426 mm specimen); anal fin III, 13 (1 with III, 13; 2 with III, 14); pectoral fin 15; pelvic fin I, 5; branchiostegal rays 7; vertebrae 16+16=32 (n=2). Scales on upper lateral line 214 (left side)/227 (right side) (196–225); on vertical part of lower lateral line 96/98 (83–86), and on horizontal part of lower branch of lateral line 237/232 (201–228+); number of pyloric caeca unknown, but appeared to be only a few.

Body rather deep and strongly compressed, body depth at pelvic-fin base 4.6 (4.5–5.6) times in SL, body width at pelvic-fin base 10.6 (9.7–10.6) in SL. Head moderately large, 3.2 (2.9–3.2) in SL. Upper profile of head gradually elevated from the tip of snout, then nearly straight to origin of dorsal fin. Snout bluntly conical. Mouth terminal and large, lower jaw slightly projecting beyond tip upper jaw; maxillary extends to a vertical of midpoint of eye.

Eye large and round, its diameter 2.5 (2.5–2.8; 3.0 in 147.5 mm specimen) times in HL; interorbital slightly concaved, one low longitudinal ridge on each frontal, least bony width 5.2 (4.9–7.1) in HL, least fleshy width 3.9 (3.9–4.7) in HL. Snout length 1.8 (1.5–1.8, 1.2 in 147.5 mm specimen) times eye diameter. Two nostrils, both at about level of middle of eye; anterior nostril rounded, directed forward; posterior nostril a vertical slit.

Front of mouth roof with 2 (2–3) fixed and 3 (3) large depressible fangs; upper jaw with 16 (15–19) blade-like teeth, widely spaced, anterior 3 (3–4) and posterior 3 (3–4) teeth fixed, others alternating fixed and depressible ones; lower jaw with a pair of canine-like teeth at front, entirely exposed when mouth closed; lower jaw with 7 or 8 (7–11) fixed blade-like teeth, the first one smallest, gradually larger posteriorly (some depressible teeth may present alternating with the fixed teeth, judging from the holes remaining in UF 34950); vomer toothless; single row of 10 or 12 (10–15) small conical teeth on palatines.

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

UF 233577 UF 34950 USNM 37238 USNM UF 233577 UF 34950 USNM 37238 USNM

391434* 391434*

Standard length (mm) 147.5 348 426 820 147.5 348 426 820 Lateral-line origin above upper end of gill opening, running backward to point of bifurcation beneath between fifth and sixth dorsal spines; upper lateral line running directly backward about parallel to dorsal contour of body to base of middle caudal-fin ray; lower branch running nearly vertically 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 middle caudal-fin ray.

Head and body mostly covered by small imbricate scales, except for lips, lower jaw, anterior half of snout and maxilla and branchiostegal membrane, which are scaleless.

Base of spinous part of dorsal fin about 2.4 (2.4–2.7; 3.0 in 147.5 mm SL specimen) of soft part; base of soft dorsal-fin about as long as that of anal fin and preceded by a weak spine anteriorly; 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, 2.0 (2.0–2.2) in HL, extending to below eighth dorsal-fin spine in neotype. Pelvic fin inserts below middle of pectoral fin, long (2.4 in HL) in 147.5 mm specimen, gradually becoming very short in adults (4.7 in HL in neotype); the fin extending to about vertical of tip of pectoral fin in neotype and to about half way between its origin and origin of anal fin in 147.5 mm specimen; pelvic-fin spine as long as longest ray in 147.5 mm specimen (2.4 in HL), and very short in neotype (7.1 in HL). Caudal fin deeply forked, upper lobe of caudal fin 1.3 (1.3–1.4; 1.7 in 147.5 mm specimen) 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 with 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 spines.

Coloration. Fresh color unknown. When preserved, body uniformly grayish to yellowish brown; ventral side of body pale or bright white.

Distribution. Known only from the Caribbean Sea off Cuba (original type locality), Bahamas (neotype locality) and Virgin Islands ( Fig. 3 ). Bathymetric range 176– 488 m. The species is most likely mesopelagic.

Etymology. The specific name magistralis meaning master or great, and may refer to its large size, based on Poey (1854). The common name, Domine, also means master or lord.

Remarks. Epinnula was previously recognized as a monotypic genus and now comprises two distinct species. Because there is no extant type specimen, the proposal of a neotype for the type species Epinnula magistralis is justified. Accordingly, a specimen (USNM 391434, 820 mm SL) from north of Bimini, Bahamas, is herein proposed as the neotype.

The records reported from the western Pacific Ocean are now recognized as a different species that is described below. The status of the only Indian Ocean record, reported by Parin & Kotlyar (1991; question mark in distribution map, Fig. 3 ), has not been confirmed, but it may also belong to the new species. See below for detailed comparison of E. magistralis to the new species.

Although there are several specimens recorded as this species in collections (e.g., UF & TU), examination on these specimens by the first author or colleagues has revealed only few that can be confirmed as E. magistralis , while others are misidentifications of other gempylids.

Some growth changes were observed in the four specimens examined. The head length shows negative allometric growth, the smallest specimen with head length 34.7% SL, whereas the largest specimen is 31.3% SL. The eye is relatively large in the smallest specimen (9.6% SL) and relatively small in the largest specimen (7.0% SL), and snout length is 1.5–1.8 times eye diameter in 3 larger specimens, whereas in the smallest specimen it is only 1.2 times eye diameter. The length of dorsal-fin spines also appears to become gradually shorter with growth.

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).

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.