Eumicrotremus uenoi Kai, Ikeguchi & Nakabo, 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 : 342-344

Eumicrotremus uenoi Kai, Ikeguchi & Nakabo , new species

http://zoobank.org/urn:lsid:zoobank.org:act:CE26C460-30E0-4488-A0F0-9E7AF3FF22C0 [New Japanese name: Sakura-dango-uo; Korean name: Eom-ji-do-chi] ( Figs. 1 C, D, 2B, 3B; Table 1)

Lethotremus awae (not of Jordan and Snyder, 1902): Kido, 1984: 337, pl. 303-I, in part, Sado Is., Niigata; Nakabo, 1993: 577, in part (Sado Is., Niigata); Nakabo, 2000: 622, in part (Sado Is., Niigata); Suzuki et al., 2000: 25, listed (Kasumi, Hyogo); Nakabo, 2002: 662, in part (Sado Is., Niigata); Nakabo and Kai, 2013: 1202, key, in part (? western coast of Honshu Is., from Aomori southward to Nagasaki); Kim, 2015: 154 ( Jeju Island ).

Lethotremus sp.: Kai et al., 2015: 398, fig. 3, Wakasa Bay, Kyoto

Eumicrotremus awae (not of Jordan and Snyder, 1902, new combination): Oku et al., 2017: 4, Sado Is., Niigata.

Holotype. FAKU 136008*, 14.2 mm SL, off Honjyo, Kyotango, Kyoto, western coast of Honshu Is, 100 m depth, 12 June 2014, R/V Ryokuyo-maru, coll. by F. Tashiro.

Paratypes. Twenty-six specimens, all from the western coast of Honshu Is. FAKU 132061* (1 specimen), 134174* (1), 10.7–10.8 mm SL, off Honjyo, Kyotango, Kyoto, 90 m depth, R/V Ryokuyo-maru. FAKU 135360* (3), 3.9–4.3 mm SL, Notojima, Ishikawa. FAKU 137315* (1), 6.66 mm SL, Sado Is., Niigata. HUMZ 79055 (1), 79071 (1), 79078 (1), 79079 (1), 79085 (1), 79087 (1), 79092 (1), 79094–79098 (5), 13.9–19.9 mm SL, Sado Is., Niigata. HUMZ 154412 (1), 154197 (1), 11.3–13.3 mm SL, Yamagata. OMNH-P 7508–7511 (4), 10.3–12.3 mm SL, Kasumi, Hyogo. PKU 56887 (1), 56889 (1), 4.2–10.0 mm SL, Otomi, Fukui.

Other materials. Five specimens. NIBR-P 4830 (1), 17.9 mm SL, Jeju Is.; PKU 6929–6930 (2), 9416* (mtDNA only, 1), 10248 (1), 8.2–17.2 mm SL, Busan, southern coast of Korean Peninsula; PKU 9198* (mtDNA only, 1), 14.3mm SL, Tongyeong, southern coast of Korean Peninsula.

Diagnosis. A species of Eumicrotremus with the following combination of characters: no spiny tubercles or fleshy papillae on body (weak if present); anterior three mandibular pores each with a barbel-like tube; interorbital and suborbital pores usually present; opercular flap rounded; ventral disk with many papillae; caudal-fin relatively short, 19.5–31.4% of SL.

Description. Counts and measurements are shown in Table 1. Holotype data given first, followed by paratype data in parentheses if different. Body globose, completely naked, lacking spiny tubercles or fleshy papillae except for larger specimens [some specimens> 18 mm SL (HUMZ 79094, 79096, 79098) with weak fleshy papillae posteriorly on body]; caudal peduncle compressed. Interorbital space broad, slightly concave. Eye small, lower margin above level of snout. Two nostrils, anterior with relatively long tube, posterior without (or with short tube). Mouth terminal, wide, slightly oblique, posterior margin of maxilla reaching to level with anterior margin of orbit (or center of orbit). Jaws with small conical teeth, arranged in four (five) diagonal rows on premaxilla, three (three to five) on dentary. Teeth on vomer and palatine absent. Gill slit short, its length much shorter than orbit diameter. Opercular flap small, rounded, directed posterodorsally.

Cephalic pores small, obscure. Nasal canal with two pores, one anterior to nostrils, the other just behind anterior nostril; interorbital canal with single median interorbital pore (absent in some paratypes: FAKU 134174, FAKU 137315, HUMZ 79094, HUMZ 79098, OMNH-P 7508, OMNH-P 7510); postorbital canal with two pores, supraorbital pore (SOP) anteriorly (except for one paratype, OMNH-P 7511) and postbranchial pore posteriorly; infraorbital canal with two (two or three) suborbital pores; operculomandibular canal with four mandibular pores along lower jaw, anteriormost pore below tip of mandibular without tube, second below posterior part of lower jaw without tube (sometimes a short tube), third below center of orbit without tube (sometimes a short tube); fourth at posteroventral margin of preopercle with relatively long tube. Free neuromasts, reduced or indiscernible, originating from above gill slit and extending downward to level at mid-body, posteriorly extending to caudal portion. In some paratypes, a pair of neuromasts present on anterior base of first dorsal fin and dorsoposterior part of eye.

Two dorsal fins; first dorsal fin shorter than second (higher in juveniles and larger specimens), 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 not reaching caudal fin base when depressed. Caudal fin short, rounded; its length usually shorter than pelvic disc length. Pectoral fins short, posterior tips usually not reaching level of posterior margin of pelvic disk; pectoral-fin base long, lowermost point below posterior margin of orbit. Pelvic disc large, round, slightly constricted anteriorly, with many papillae. Anus approximately midway between posterior margin of pelvic disc and anterior origin of anal fin.

Color when fresh ( Fig. 1 E, F). Based on holotype and three paratypes, FAKU 134174, 137315, 135360. Body and head variable, from dark or light green (FAKU 134174) to dark red (FAKU 137315) overall with or without dark brown dots. FAKU 137315 with short white bars radiating from eye. Juveniles with a white line running longitudinally through eyes, and a white transverse band between trunk and caudal regions of body. First dorsal fin variable, from dark or light green (FAKU 134174) to dark red (FAKU 137315); second dorsal, anal and caudal fins, and dorsal portion of pectoral fin translucent, lowermost five (five or six) pectoral fin rays dark brown; ventral disc white, margined with dark brown.

Color in preservative. In 70% ethanol, body and head dark, with or without dark brown dots. Juveniles with a white ring running longitudinally through eyes, and a white transverse band between trunk and caudal regions of body. Dark spot on supraorbital pore. Tubes of mandibular pores dark. Larger specimens (> ca. 18.0 mm SL) with a dark spot above anal fin origin. First dorsal fin pale; second dorsal fin, anal fin, and caudal fin translucent; dorsal portion of pectoral fin translucent, lowermost five (five or six) rays dark.

Distribution. Known from the southern coast of Korean Peninsula (Busan, Tongyeong and Jeju Island) and off the western coast of Honshu Is. from Yamagata southward to Hyogo ( Fig. 4 ).

Etymology. Named in honor of Dr. Tatsuji Ueno, formerly of the Hokkaido Fisheries Experimental Station, who contributed greatly to the systematics of Cyclopteridae .

Remarks. Eumicrotremus uenoi has long been confused with E. awae , but is distinguishable from the latter in usually having interorbital and supraorbital pores. The former is distributed from Yamagata southward to Hyogo, western coast of Honshu Is. and along the southern coast of the Korean Peninsula (based on voucher specimens), being allopatric to E. awae ( Fig. 4 ). Although many authors have reported “ L. awae ” from (or near) the distributional range of E. uenoi , including Shiogaki and Dotsu (1973) (Nagasaki, coast of northern East China Sea ), Honma et al. (2006) (Niigata), Nagamatsu (2009) ( East China Sea ), Yamasaki (2013) (Nagasaki) and Kawano et al. (2014) (Aomori southward to Nagasaki, western coast of Honshu Is.), these reports cannot now be attributed with certainty to E. uenoi due to their lacking definitive descriptive characters. Although Suzuki et al. (2000) listed L. awae from Kasumi, Hyogo, their specimens were actually E. uenoi and are now included among the paratypes of that species. In addition, Kim (2015) reported and described L. awae on the basis of specimens collected from Jeju Island . Examination of four of those specimens confirmed their identity as E. uenoi due to the presence of interorbital and supraorbital pores, and many papillae on the ventral disk. Chu & Jin’s (1963) description of L. awae from the northern East China Sea noted many papillae on the ventral disk, as found here in specimens of both E. awae and E. uenoi . However , the present specimens of both species differed from Chu & Jin’s (1963) description in lacking spots on the second dorsal and anal fins.

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 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.