Eviota specca, Greenfield, David W., Suzuki, Toshiyuki & Shibukawa, Koichi, 2014

Greenfield, David W., Suzuki, Toshiyuki & Shibukawa, Koichi, 2014, Two new dwarfgobies of the genus Eviota from the Ryukyu Islands, Japan (Teleostei: Gobiidae), Zootaxa 3774 (5), pp. 481-488 : 485-487

Eviota specca n. sp.

Speckled Dwarfgoby

New Japanese-name: Kumadori-Isohaze ( Figs. 4 & 5 )

Holotype. NSMT-P 114945, 12.1 mm, immature, Hatoma-jima Island, the Ryukyu Islands, Japan, 24.4721N, 123.8019E, 5–14 m depth, field number S-18742, Toshiyuki Suzuki, Koichi Shibukawa, Masatomi Suzuki & Akira Kawai, 14 August 2010.

Diagnosis. The following combination of characters distinguish E. specca from congeners: cephalic sensorypore system pattern 1 (complete), dorsal/anal-fin formula 8/8; body heavily sprinkled with chromatophores; pigment on upper pectoral-fin base; four subcutaneous body bars between anal-fin origin and caudal-fin base; no occipital spot; opercular membrane pale; first dorsal fin sprinkled with small melanophores and chromatophores; caudal peduncle without distinct dark spot or bar; cheek crossed by dark lines, no red spots.

Description. Dorsal-fin rays VI-I,8, 4–8th soft rays branched, the last ray branched to base; anal-fin rays I,8, 6– 8th soft rays branched, the last ray branched to base; pectoral-fin rays 16, 11–15th rays branched, pectoral fin reaching to 4th anal-fin ray base; pelvic fins without basal membrane, no pelvic frenum, pelvic-fin membrane reduced, pelvic-fin rays I,5, 4th pelvic-fin ray with 6 branches, 1 segment between branches, 5th segmented pelvicfin ray 3.5% of 4th ray, pelvic fins reaching to second anal-fin ray base; caudal-fin broken; lateral scale rows 22, transverse scale rows 5, no scales on head, nape, breast, pectoral-fin base, belly and narrow areas along bases of first dorsal fin, scales on body finely ctenoid; vertebrae 10+16 = 26; dorsal-fin spines not filamentous, not extending back to origin of second dorsal fin; cephalic sensory-pore system pattern 1 (complete): anterior oculoscapular canal with pores B', single C, single D, E, F and G', two preopercular-canal pores, N' and O'; immature genital papilla undeveloped, not reaching to anal-fin origin; mouth oblique, both jaws equal, maxilla extending posterior to vertical at center of pupil; anterior tubular nares extending to upper lip and dark in color; gill opening extending forward to a quarter from posterior end of opercular membrane, gill membranes attached anteriorly to isthmus, without free fold.

Measurements. Standard length 12.1 mm; head length 30.3; origin of first dorsal fin 38.6, above posterior end of pectoral-fin base; origin of second dorsal fin 58.3; origin of anal fin 60.6, at vertical through 1st soft ray of second dorsal fin; caudal-peduncle length 25.2; caudal-peduncle of moderate depth 12.6; body of moderate depth 21.3; eye diameter 9.1; snout length 5.9; upper-jaw length 11.8; pectoral-fin length 33.9; pelvic-fin length 31.5.

Color in preservative of holotype ( Fig. 4 ). Background color of head and body very pale yellow, almost white. Body with heavy sprinkling of small chromatophores, head with fewer larger chromatophores in the following patterns: triangular concentration of chromatophores on top of head behind eye; concentration of chromatophores on operculum just posterior to preoperculum, forming bar, a cluster of chromatophores above this at upper edge of operculum. Three bars under eye: first angling anteroventrally across jaws; second under middle of eye, extending ventrally behind jaws; third, the most distinct, behind and slightly below middle of eye, extending posteroventrally across cheek. Jaws with smaller scattered chromatophores and melanophores. Anterior tubular nares sprinkled with melanophores. Pupil of eye clear, iris black. Nape crossed by four bars composed of scattered chromatophores. Top of pectoral-fin base with bar of chromatophores, angling back posteroventrally. Body with six subcutaneous bars: first behind the pectoral-fin base extending dorsally to first three elements of first dorsal fin; second at posterior half of first dorsal fin; third from origin of second dorsal fin to anal-fin origin; fourth at end of anal fin, fifth and sixth on caudal peduncle, sixth bar slightly darker at its center. Top of bars visible as dark blotches on dorsal surface of body, three under first dorsal fin and three under second dorsal fin. Dorsal, anal, and caudal fins heavily peppered with chromatophores and melanophores, latter mostly on upper half of fins, distal margins clear. Pectoral-fin membranes clear, rays with narrow dark margins. Pelvic fins immaculate.

Color of fresh holotype ( Fig. 5 ). Background color of head and body translucent white. The basic color pattern same as described for preserved holotype, but dark markings on head, nape, dorsal surface of body, and pectoral-fin base are underlain with yellow. The anteroventral bar under the eye that crossed the jaws also has a slight reddish tinge. There also is a light scattering of small yellow spots mixed with darker chromatophores on the body, more concentrated on dorsal half. Bases of dorsal fins with yellow mixed with dark chromatophores on lower half and spines, rays whitish.

Distribution. Iriomote-jima Island, the Ryukyu Islands, Japan ( Suzuki et al., 2004; in this study). Etymology. The specific epithet is based on the Anglo/Saxon specca (speckled) referring to the heavy speckling of chromatophores over the body. The name is treated as a noun in apposition.

Comparisons. Eviota specca is a member of the cephalic sensory-pore pattern 1 (complete) with 32 described species ( Greenfield & Jewett, 2014 - Table 1). Only eight of the species in pattern 1 share the dorsal/anal-fin formula of 8/8 with E. specca : E. distigma Jordan & Seale, E. herrei Jordan & Seale, E. monostigma Fourmanoir , E. nebulosa Smith , E. nigramembrana Greenfield & Suzuki , E. nigripinna Lachner & Karnella , E. randalli Greenfield , and E. winterbottomi Greenfield & Randall. The complete pectoral-fin base is dark in E. monostigma (upper half in E. specca ); three subcutaneous body bars between anal-fin origin and caudal-fin base in E. randalli (four in E. specca ); opercular membrane dark in E. nigramembrana (clear in E. specca ); E. distigma with two dark spots on pectoral-fin base in males and with an obvious dark spot on the caudal peduncle over the posteriormost subcutaneous bar (both absent in E. specca ); body deep in E. herrei , 24.8–28.5% SL (more slender in E. specca , 21.4%) and 5th pelvic-fin ray 20% of 4th (3.5% in E. specca ); E. nigripinna with an obvious dark spot on the caudal peduncle, the dorsal fin solid black, and the nape crossed by four orange bars (all absent in E. specca ); E. nebulosa has a caudal spot located above the midline on the posteriormost subcutaneous bar, no dark pigment on pectoral-fin base, and dorsal fin with broad dark and light bars ( E. specca lacks a caudal spot above the midline, has pigment on the upper pectoral-fin base, and the dorsal fin is not crossed by dark and light bars); E. winterbottomi has a complete dark bar over the posteriormost subcutaneous bar, whereas it is not obvious in E. specca and E. winterbottomi has round red spots on the cheek in life ( E. specca lacks them).

Remarks. One other species of Eviota also has a heavy speckling of chromatophores on the body like E. specca , E. piperata ; however, it lacks the IT pore, has small chromatophores covering the head as well as the body, the entire pectoral-fin base is covered with pigment, and has larger chromatophores on the dorsal fins ( Greenfield & Winterbottom, 2014).

Figures

FIGURE 4. Preserved holotype of Eviota specca, NSMT 114945. Photograph by Toshiyuki Suzuki.

FIGURE 5. Freshly collected holotype of Eviota specca, NSMT 114945. Photograph by Koichi Shibukawa.