Eviota rubrimaculata, Suzuki, Toshiyuki, Greenfield, David W. & Motomura, Hiroyuki, 2015

Suzuki, Toshiyuki, Greenfield, David W. & Motomura, Hiroyuki, 2015, Two new dwarfgobies (Teleostei: Gobiidae) from the Ryukyu Islands, Japan: Eviota flavipinnata and Eviota rubrimaculata, Zootaxa 4007 (3), pp. 399-408 : 404-407

Eviota rubrimaculata n. sp.

Redspot Dwarfgoby

New Japanese-name: Zakuro-Isohaze ( Figs. 7–10 )

Eviota sp. 4. Suzuki 2014: 517 (Yoron Island, the Ryukyu Islands, Japan).

Holotype. KPM-NI 30770, 12.0 mm, female, off Maehama, Yoron Island, the Ryukyu Islands, Japan, 6-8 m depth, 27°01ʹ13ʺN, 128°26ʹ26ʺE, KAUM Fish Team, 14 Aug. 2012.

Diagnosis. A species of Eviota with cephalic sensory-canal pore system pattern 2 (lacking only H [IT] pore); some pectoral-fin rays branched; dorsal/anal fin-ray formula 9/8; 5th pelvic-fin ray absent; no prominent distinct dark spots on pectoral-fin base; no caudal-peduncle spot over preural centrum; no postocular spots; no strong, dark spots on caudal fin. Two dark spots over anal-fin base; first dorsal fin clear with some light orange on anterodorsal portion and dark distal margin; second dorsal fin with red-orange spots on basal half, distal margin black and yellow; body with bright red markings.

Description. Dorsal-fin rays VI-I,9, first dorsal fin triangular in shape, first spine longest and slightly elongated, but all spines not filamentous (not extending back to origin of second dorsal fin), all second dorsal-fin soft rays branched except first soft ray, the last ray branched to base; anal-fin rays I,8, all soft rays branched, the last ray branched to base; pectoral-fin rays 16, 11–15th rays branched, pectoral fin reaching to above third anal-fin soft ray base; pelvic fins without basal membrane, no pelvic frenum, pelvic-fin membrane reduced, pelvic-fin rays I,4, 4th pelvic-fin ray with 5 branches, 1-2 segments between branches, pelvic fins reaching to anal-fin origin; 13 branched and 17 segmented caudal-fin rays; lateral scale rows 23, transverse scale rows 5, no scales on head, nape, breast, pectoral-fin base, midline of belly and narrow areas along base of first dorsal fin, scales on body finely ctenoid except belly where they are cycloid; cephalic sensory-canal pore system pattern 2 (lacking only the H (IT) pore): anterior oculoscapular canal with pores B', single C, single D, E and F', two preopercular-canal pores, N' and O'; female urogenital papilla smooth, bulbous, with six short finger-like projections on end, not reaching to anal-fin origin; mouth oblique, both jaws equal, maxilla extending posterior to vertical at center of pupil; anterior nares tube not extending to upper lip and not dark in color; gill opening extending forward to below posteroventral edge of operculum, gill membranes attached anteriorly to isthmus.

Measurements. Standard length 12.0 mm; head length 31.7; origin of first dorsal fin 42.9, slightly behind above posterior end of pectoral-fin base; origin of second dorsal fin 62.7; origin of anal fin 64.3, at vertical through second soft ray base of second dorsal fin; caudal-peduncle length 23.0; caudal-peduncle depth 11.1; body depth 20.6; eye diameter 9.5; snout length 6.0; upper-jaw length 11.5; pectoral-fin length 31.7; pelvic-fin length 30.2.

Color in preservative of holotype ( Figs. 7 & 8 ). Background color of head and body translucent gray. Iris of eye black, pupil clear. A large brown-orange blotch behind upper half of eye and top of head. Cluster of dark chromatophores on snout above nares tube, another dark cluster at end of upper jaw. Scattered individual or clusters of dark chromatophores on side of head, more concentrated around eye, with a line of dark chromatophores extending from eye at five o’clock position to gular area. Operculum with scattered dark chromatophores and a pinkish wash extending to pectoral-fin base through cluster of dark chromatophores crossing center of base. Body with very few small dark chromatophores, mostly above midline. Edges of scales on dorsum under second dorsal fin dark. First dorsal fin mostly clear with a few dark chromatophores along basal half and more on distal margin of fin. Second dorsal fin with scattered dark chromatophores on rays and small dark chromatophores on distal margin. Caudal fin with a few scattered dark chromatophores on rays. Anal fin dusky, darker than other fins. Pectoral and pelvic fins immaculate.

Color of fresh holotype ( Figs. 9 & 10 ). Background color of head and body translucent gray-white. Most obvious markings red spots on areas as described below. Pupil of eye black, iris silver with red spokes radiating out from the pupil. Red blotches around eye; two between eye and upper jaw, one at eight o’clock, a second at seven o’clock. Long red line extending from under eye at six o’clock down behind jaws onto gular area. Side of head with several scattered large red spots mixed with black chromatophores extending up to behind eye. Series of red lines extending back from lower edge of preoperculum and operculum across branchiostegals. Pectoral-fin base with two red bars, one dorsal and one ventral, separated by yellow area filed with small dark chromatophores. Top of head, nape and area under pectoral-fin base white, side of abdomen with two large red spots followed by smaller spot above anal opening. Lower part of abdomen white, both upper and lower areas heavily peppered with large dark chromatophores. Upper half of body translucent gray with just a few scattered scales with dark margins. Grayblue line along vertebral column. Ventral half of body with six red spots, two over anal-fin base and four more on ventral edge of caudal peduncle. Each of these spots, except last at caudal-fin base, with dark subcutaneous bar extending up to just below vertebral column. Series of small white spots, about half the size of pupil, on body; anteriormost behind second large red spot on abdomen, second above anal-fin origin, third above center of anal fin, fourth at end of anal fin, fifth and sixth on caudal peduncle near vertebral column, and seventh at top of caudal peduncle. First dorsal fin clear with some light orange on anterodorsal portion and a dark distal margin. Second dorsal fin with red-orange spots on basal half, distal margin black and yellow. Anal fin black, with two red areas extending from body spots onto basal portion of fin. Caudal fin with scattered orange spots on central rays and light gray spots on remaining rays. Pectoral and pelvic fins immaculate.

Distribution. Yoron Island, the Ryukyu Islands, Japan (Suzuki 2014; in this study).

Etymology. The specific epithet is an adjective from the Latin rubra (red) and macula (spot) in reference to the distinctive red spots on E. rubrimaculata ’s head and body.

Comparisons. Eviota rubrimaculata is most similar to E. flavipinnata , differing only in lacking the 5th pelvicfin ray, whereas it is 12% of the 4th ray in E. flavipinnata , and in coloration, with the first dorsal fin mostly clear and anal fin black in E. rubrimacula , whereas it is bright golden-yellow and anal fin orange in E. flavipinnata . The specimens of E. flavipinnata and E. rubrimaculata are both females, eliminating sexual dimorphism as an explanation of color differences between the two. The separation from other species of Eviota with cephalic sensory-canal pore pattern 2 (lacking only the H [IT] pore) and branched pectoral-fin rays, is the same as for E. flavipinnata (Table 1), with the fresh coloration also differing from E. afelei , E. bimaculata , and E. punctulata ( Figs. 4 , 5 , 6 ).

Remarks. Both E. flavipinnata and E. rubrimaculata share many characters in common, differing only in the development of the 5th pelvic-fin ray and major differences in fresh coloration. In their discussion of cryptic goby species within the Coral Triangle, Tornabene et al. (2015) demonstrated that coloration in various Eviota complexes appears to evolve rapidly, before their genetic differences are reflected in their morphology. It is possible that this may be another example of species that have evolved recently.

Figures

FIGURE 4. Eviota bimaculata, freshly collected specimen, Jurien Bay, Australia. Photograph by J. B. Hutchins.

FIGURE 5. Eviota punctulata, freshly collected specimen under water, Fiji. Photograph by J. E. Randall.

FIGURE 6. Eviota afelei, freshly collected specimen, Moorea. Photograph by J. T. Williams.

FIGURE 7. Eviota rubrimaculata, preserved holotype, KPM-NI 30770, light background. Photograph by Toshiyuki Suzuki.

FIGURE 8. Eviota rubrimaculata, preserved holotype, KPM-NI 30770, dark background. Photograph by Toshiyuki Suzuki.

FIGURE 9. Eviota rubrimaculata, freshly collected holotype, KPM-NI 30770, dark background. Photograph by Hiroshi Senou.

FIGURE 10. Eviota rubrimaculata, freshly collected holotype, KPM-NI 30770, light background. Photograph by Hiroshi Senou.