Epinnula 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 : 394-395

Epinnula Poey, 1854

Epinnula Poey, 1854:369 (type species: Epinnula magistralis ; by original designation and monotypy). Collette et al., 1984:600. Nakamura in Masuda et al., 1984:226. Parin & Kotlyar, 1991:137. Nakamura & Parin, 1993:26. Parin & Nakamura, 2003:1814.

Diagnosis. Members of Gempylidae with a deep and compressed body; entire body covered with minute imbricated scales. Several fangs either fixed or depressible, on anterior portion of upper jaw. Vomer without teeth. Palatine with single row of small conical teeth. Lateral line bifurcating beneath anterior part of spinous dorsal; upper lateral line continuing roughly parallel to dorsal profile to base of caudal fin; lower lateral running vertically to lower base of pectoral fin and then along the lower body profile to base of caudal fin. Dorsal fin inserted above upper angle of gill opening; two dorsal fins close to each other with a deep notch between the fins. Pelvicl fin welldeveloped, fin spine and rays well developed. Finlets and keels absent on tail. Gill raker at angle of first gill arch Tshaped, with smooth inner surface. Pyloric caeca 7–11. Epineurals 2. Dorsal fin XV–XVI, I, 15–18, anal fin III, 13–17, pectoral fin 15 or 16, and pelvic fin I, 5.

Description. Body deep, slender and laterally compressed; deepest at level of pelvic fin, gradually narrowing to caudal peduncle; dorsal profile of body straight, ventral slightly convex; body depth at pelvic-fin base 3.7–4.6 in SL. Head moderately large, 2.9–3.3 in SL; head triangular in lateral view; dorsal profile of head broadly curved and straight behind the eye or evenly straight. One or two small spines on lower angle of preopercle. Snout triangular, broadly pointed anteriorly. Mouth large, rear end of maxilla reaches level of eye center or nearly so; lower jaw extends anterior to upper jaw; several fangs, either fixed or depressible, at anterior portion of upper jaw, single row of smaller compressed teeth on upper jaw, alternating fixed and depressed ones; a pair of large canines near tip of lower jaw, exposed externally when mouth closed; single row of scattered compressed teeth on lower jaw, teeth larger than those on upper jaw; vomerine teeth absent; a single row of conical teeth on each palatine.

Two dorsal fins close to each other with a deep notch between the fins; first dorsal-fin relatively high, 4th to 7th spines longest, its origin above upper end of gill opening; second dorsal fin about same height as first dorsal or slightly higher, a slight concavity at middle portion of the fin. Pectoral fin originating at level of second dorsal-fin spine, moderately long, straight dorsally, rounded ventrally and posteriorly, the 4th or 5th ray longest, rays gradually shorter ventrally. Ventral fin originating at level of 5th dorsal-fin spine, very large in juveniles, small in adults. Anal fin slightly smaller than second dorsal fin, its origin at posterior one-third of body. Finlets absent from caudal peduncle; caudal fin deeply forked, upper lobe slightly larger than lower lobe.

Body scales cycloid, small and deciduous, covering most parts of head and maxilla, small naked areas on anterior snout and premaxilla; most of lower jaw naked. First dorsal fin naked, scales on base of other fins. Lateral line scales slightly larger than body scales, upper lateral line beginning above upper end of gill opening, running roughly parallel to dorsal profile of body, then gradually descending from origin of second dorsal fin to base of caudal fin; lower lateral line originating from the upper lateral line at about level of 5th to 6th dorsal-fin spine, its vertical portion wave-shaped, its horizontal portion running parallel to lower body profile, then gradually rising from middle of body to base of caudal fin.

Fresh and preserved body color generally dark gray with all fins darker.

Size. To about 1 m TL.

Etymology. The name Epinnula refers to the lack of spinules [referred to as finlets herein].

Remarks. Poey (1854) defined the genus as " first dorsal fin continuous, extending to the second dorsal fin, the second terminates without spinules; ventral fin present on abdomen; second lateral line similar to coselete [girdle], but without difference in the size of scales; no keel or membranous crest on caudal peduncle; teeth pointed and compressed, anterior ones larger and canines; no teeth on vomer and palatine; not many pyloric caeca. " He suggested that the genus Epinnula " should be placed between Thyrsites and Gempylus [under the family Gempylidae ], to which it resembles in having extension of the first dorsal to the second, the naked caudal peduncle [e.g. lack of finlets], the teeth on the jaws, and the low number of pyloric caeca. "

The "second [dorsal fin] terminates without spinules" likely infers the lack of finlets in this genus. Moreover, there is single row of teeth on palatine in all specimens examined and “no teeth on palatine” as stated by Poey (1854) is apparently a mistake.