Eviota ancora, Greenfield, David W. & Suzuki, Toshiyuki, 2011

Greenfield, David W. & Suzuki, Toshiyuki, 2011, Two new goby species of the genus Eviota from the Ryukyu Islands, Japan (Teleostei: Gobiidae), Zootaxa 2812, pp. 63-68 : 63-66

Eviota ancora n. sp.

Hookcheek Pygmygoby New Japanese name—Bonbori-Isohaze ( Figs. 1– 3 )

Eviota sp. 7. Senou et al., 2004: 147 (underwater photograph, Iriomote-jima Island, the Ryukyu Islands, Japan, 6 m depth).

Holotype: OMNH-P21096, 14.0 mm SL male, Japan, the Ryukyu Islands, Iriomote-jima Island, Uehara Beach, (24°25’03.27”N, 123°48’07.36”E), T. Suzuki & M. Suzuki, August 19, 2005.

Diagnosis. The following combination of characters distinguishes E. ancora from congeners: cephalic sensory-pore system pattern group 2 (lacking only IT pore); dorsal/anal fin-ray formula 8/7; pectoral-fin rays simple; 5th pelvic-fin ray 10% of 4th; no conspicuous dark marks on body; scales not strongly pigmented; caudal fin with five irregular bands of circles of dark chromatophores crossing the fin; live or fresh specimens with a hook-shaped orange mark on side of the head.

Description. Dorsal-fin rays VI+I,8; anal-fin rays I,7; pectoral-fin rays 16, rays not branched; 5th segmented pelvic-fin ray 10% of 4th ray; branches on 4th pelvic-fin ray 4, 4 segments between branches; 12 branched caudalfin rays; segmented caudal-fin rays 17; lateral scale rows 23; transverse scale rows 7; breast and pectoral-fin base scaleless; anterior spines of first dorsal fin extending just past origin of second dorsal fin; pelvic fins reaching to third anal-fin ray; cephalic sensory-pore system pattern group 2 (only IT missing); male genital papilla non-fimbriate.

Measurements. Standard length 14.0 mm; head length 32.5; origin of first dorsal fin 37.5; origin of second dorsal fin 58.2; origin of anal fin 61.1; caudal-peduncle length 27.1; caudal-peduncle depth 13.6; body depth 20.7; eye diameter 8.2; snout length 4.3; upper-jaw length 12.5; pectoral-fin length 31.1; pelvic-fin length 35.7.

Color. Color of freshly collected male holotype, OMNH-P21096: ( Fig. 1 ) Body translucent with a series of eight internal dark dashes spaced above vertebral column, with silver dashes between them. Another series of dark triangular spots below the vertebral column, the ones over the abdomen larger. Six internal dark marks between the anal-fin origin and caudal-fin base with silver between them. Abdomen silver, with two orange bars crossing it dorsoventrally. Head translucent with an orange bar under the eye and another orange stripe behind the eye extending posteriorly to the opercle. A silver area above this orange stripe extending across the cheek and onto the pectoralfin base. A short orange area above the silver area behind the eye. A crescent shaped orange mark on the posterior portion of the opercle, joining the orange stripe from the eye to form a hook-shaped mark. Orange extends from the crescent to the ventral portion of the pectoral-fin base. Tubular nostrils orange. Entire side of head with a heavy peppering of small, black chromatophores. Nape with four distinct orange spots extending from behind the eyes to the first dorsal-fin base. Nine dark spots on dorsal midline extending from first dorsal fin to caudal-fin base. First dorsal fin with a band of small, black chromatophores along its base. Lower third of second dorsal fin with scattered dark chromatophores and some orange pigment; distal two thirds crossed by three bands of dark chromatophores on rays. Anal fin dusky. Caudal fin with five irregular bands of circles of small, black chromatophores on larger red spots crossing the fin; lower portion of caudal fin dusky. Pectoral and pelvic fins clear.

Color in life: ( Fig. 2 ) Color similar to fresh specimen except: area under eye is white; spots on dorsal midline dark orange; dorsal portion of eye white with orange marks; black and orange areas over silver abdomen more obvious; pupil green surrounded by an orange ring and the iris is black; and the hook-shaped orange mark on side of head obvious.

Color of holotype in preservative: ( Fig. 3 ) Background color of body and head pale yellowish with no bold markings. Scattered small black chromatophores on snout, both jaws, top of head behind eyes, and on side of head on cheek and opercle. A few scattered small, black chromatophores on pectoral-fin base, with some extending onto the ventral part of the fin. Three small clusters of small, black chromatophores spaced out along midline of nape in front of first dorsal fin. A scattering of small, black chromatophores along base of first dorsal fin. A few clusters of chromatophores, similar to those on the nape, along the base of the second dorsal fin and the dorsal and ventral surfaces of the caudal peduncle. Second dorsal fin with a few small chromatophores scattered over entire fin, with a greater concentration on the distal margin. Anal fin more heavily peppered than second dorsal fin, making it darker than the other fins. Caudal fin with five irregular bands of circles of small chromatophores crossing the fin. Pelvic fins immaculate.

Distribution. Amami-oshima Island, Kume-jima Island and Iriomote-jima Island, the Ryukyu Islands, Japan ( Senou et al., 2004; In this study).

Etymology. The specific epithet is an adjective from the Latin ancora (hooked) referring to the distinctive orange hook-shaped marking on the side of the head.

Comparisons. Eviota ancora belongs to the cephalic sensory-pore pattern group 2 of Lachner and Karnella (1980), lacking only the IT pore. Eviota ancora differs from all other species of Eviota by its distinctive color pattern, particularly the hook-shaped orange coloration on the side of the head. It differs from species in cephalic sensory-pore pattern group 2 as follows: the following species have branched pectoral-fin rays whereas they are simple in E. ancora – E. afelei , E. bimaculata , E. hoesei , E. indica , E. japonica , E. latifasciata , E. pellucida , E. prasina , E. punctulata ,, E. queenslandica , E. rubra , E. rubrisparsa , E. saipanensis , E. tigrina , E. variola , and E. zonura ; from those with simple pectoral-fin rays by having a dorsal/anal fin-ray formula of 8/7 whereas, E. cometa , E. sigillata , E. spilota , and E. zebrina usually have values of 9/8 or 9/7; from those with dorsal/anal values of 8/7 by having a shorter 5th pelvic-fin ray, 10% the length of the 4th ray, whereas it is longer (modally 40%) in E. pellucida and E. prasites ; and from E. storthynx , with shorter 5th pelvic-fin rays, by lacking the dark occipital spot present in that species.

Remarks. Eviota ancora shares the most characters with E. storthynx , but differs greatly from it in color.

Figures

FIGURE 1. Freshly collected male holotype of Eviota ancora, OMNH-P 21096. Photograph by Toshiyuki Suzuki.

FIGURE 2. Underwater photograph of Eviota ancora, about 2.2 cm TL, Kasari-wan Inlet, Amami-oshima Island, the Ryukyu Islands, Japan, 14 m depth. Photograph by Hiroyuki Kanehara.

FIGURE 3. Preserved holotype of Eviota ancora, OMNH-P 21096. Photograph by D. W. Greenfield.