Eumicrotremus jindoensis Lee and Kim, 2017

Lee, Soo Jeong, Kim, Jin-Koo, Kai, Yoshiaki, Ikeguchi, Shin’Ichiro & Nakabo, Tetsuji, 2017, Taxonomic review of dwarf species of Eumicrotremus (Actinopterygii: Cottoidei: Cyclopteridae) with descriptions of two new species from the western North Pacific, Zootaxa 4282 (2), pp. 337-349 : 344-346

Eumicrotremus jindoensis Lee and Kim , new species

http://zoobank.org/urn:lsid:zoobank.org:act:03B6D01F-9690-4C95-A117-33E0B8D22BD7 [New Korean name: Gin-kko-ri-eom-ji-do-chi]

( Figs. 1 E, F, 2C, 3C; Table 1)

Lethotremus awae (not of Jordan and Snyder, 1902): Ding, 1987: 408, Liaoning; Jin, 2006: 619, fig. 277, Liaoning, Shandong, northern East China Sea.

Holotype. PKU 10232* (mtDNA only), 19.7 mm SL, Jin-do, southwestern coast of Korean Peninsula, 18 April 2013, bag net, 20–30 m depth, coll by Jin-Koo Kim.

Paratype. PKU 10233* (mtDNA only), 24.8mm SL, collection data as for holotype.

Diagnosis. A species of Eumicrotremus with the following combination of characters: no spiny tubercles or fleshy papillae on body; anterior one to three mandibular pores each with a short barbel-like tube; interorbital pore absent; suborbital pore present; opercular flap triangular; papillae on ventral disk absent; caudal-fin long, 32.7–42.1% of SL.

Description. Counts and proportional measurements are shown in Table 1. Body globose, completely naked without spiny tubercles or fleshy papillae; caudal part of body compressed. Interorbital space broad, flat. Eye moderately large, located much closer to snout than to gill opening. Mouth large, somewhat oblique; upper jaw projecting slightly beyond lower jaw; posterior margin of maxilla reaching below level of center of orbit. Jaws with conical teeth irregularly arranged in two or three rows; teeth on innermost row somewhat larger. Teeth on vomer and palatine absent. Gill slit short, its length much shorter than orbit diameter, located below origin of first dorsal fin and not reaching upper pectoral origin. Opercular flap triangular, directed posterodorsally,

Cephalic pores small or indiscernible ( Fig. 2 B). Nasal canal with no visible pores; interorbital canal without pores; postorbital canal with postbranchial pore; infraorbital canal without pores; operculomandibular canal with four mandibular pores along lower jaw, posterior three (third only in paratype) with a short barbel-like tube; anteriormost pore below tip of mandibular, second below posterior part of lower jaw, third below center of orbit; fourth at posteroventral margin of preopercle. Free neuromasts reduced or indiscernible.

Two dorsal fins, first dorsal fin somewhat shorter than second; first dorsal fin without spiny tubercles; second dorsal fin located slightly anterior to opposite anal fin, length and height almost equal, without spiny tubercles. Second dorsal and anal fins extending beyond caudal fin base when depressed. Caudal fin long, rounded, its length greater than pelvic disc length. Pectoral fins short, posterior tips not reaching level of posterior margin of pelvic disk; pectoral-fin base long, lowermost point below posterior margin of orbit. Pelvic disc large, somewhat elliptical, without papillae ( Fig. 3 ). Anus located much closer to ventral disk than to anal fin origin.

Eumicrotremus awae Eumicrotremus uenoi Eumicrotremus jindoensis

Non-type Holotype Paratypes Other materials Holotype Paratype Color in preservative ( Fig. 1 C, D). In 70% ethanol, head and body pale with numerous melanophores, except around anus. First dorsal fin dark; second dorsal, anal, caudal and pectoral fins translucent. Ventral disc white, with dark margin.

Distribution. In addition to the type locality, literature records ( Ding, 1987; Jin, 2006) suggest that the species is distributed in the Yellow Sea ( Fig. 4 ; see below Remarks).

Etymology. The specific name “ jindoensis ” is derived from the type locality, Jin-do Island.

Remarks. Li’s (1955) description of “ L. awae ” on the basis of specimens collected from the Bohai Sea, China, included barbel-like tubes under the mandible, a triangular opercular flap, and a pale body with numerous melanophores. Those characters closely matched the present specimens of E. jindoensis . Although Li (1955) noted that the specimens lacked sensory pores, this may have simply reflected the difficulty of discerning them. However, the caudal fin length (27.5% SL) closely matched those of E. awae and E. uenoi , making the identification of Li’s (1955) species somewhat equivocal. The descriptions of L. awae given by Ding (1987) and Jin (2006) agreed with the present specimens of E. jindoensis in having barbel-like tubes under the mandible, a triangular opercular flap, a pale body with numerous melanophores, and no (= indiscernible) sensory pores. Jin (2006) also noted a long caudal fin (32.1% SL), similar to the present specimens of E. jindoensis .

Figures

FIGURE 1. Three dwarf species of Eumicrotremus from the western North Pacific. (A) Eumicrotremus awae, FAKU 135824, 24.4 mm SL, fresh condition; (B) E. awae, FAKU 134725, 18.1 mm SL, fresh condition; (C) E. uenoi, FAKU 136008, holotype, 14.2 mm SL, fresh condition; (D) E. uenoi, PKU 10248, non-type, 17.2 mm SL, fresh condition; (E) E. jindoensis, PKU 10232, holotype, 19.7 mm SL, preserved condition; (F) E. jindoensis, PKU 10233, paratype, 24.8 mm SL, preserved condition. Scale bars equal to 5 mm.

FIGURE 2. Sensory pores of the three dwarf species of Eumicrotremus. (A) Eumicrotremus awae, KPM-NI 31619, 22.2 mm SL; (B) E. uenoi, FAKU 136008, holotype, 14.2 mm SL; (C) E. jindoensis, PKU 10232, paratype, 19.7 mm SL. INP, internasal pore; IOP, interorbital pore; SOP, supraorbital pore; SOP’, branch from supraorbital pore; SUP, suborbital pores; OMP, operculomandibular pores.

FIGURE 3. Ventral disk of three dwarf species of Eumicrotremus. (A) Eumicrotremus awae, CAS-SU 6971, holotype, photo by California Academy of Sciences; (B) E. uenoi, FAKU 136008, holotype, 14.2 mm SL; (C) E. jindo, PKU 10232, holotype, 19.7 mm SL.

FIGURE 4. Collection cites of three dwarf species of Eumicrotremus from the western North Pacific. Squares, stars, and circles indicate E. awae, E. uenoi and E. jindoensis, respectively. Closed symbols—based on specimens examined in this study; open symbols—based on literature records.