Eviota notata, Greenfield, David W. & Jewett, Susan L., 2012

Greenfield, David W. & Jewett, Susan L., 2012, Two new Gobiid fishes of the genus Eviota from the Indian Ocean (Teleostei: Gobiidae), Zootaxa 3515, pp. 67-74 : 68-71

Eviota notata n. sp.

Barhead Dwarfgoby ( Figs. 1–4 )

Holotype: ANSP 145893, 13.4 mm male, Seychelles, Mahe Island vicinity, inner edge of reef, N. of Anonyme Island, ~ 4.6°S, 55.5°N, 0–1.6 m, 4 February 1964, field number F-23, J.E. Böhlke et al.

Paratypes: SEYCHELLES (collected during the International Indian Ocean Expedition of 1964 by J.E. Böhlke et al.): USNM 221757, 3 (12.4–12.9), taken with holotype. USNM 221755, 5 (10.1–13.7); ANSP 146510, 5 (11.2–12 7); CAS 47917, 3 (11.7–13.3); AMS I. 22204-001, 2 (13.2, 13.8); BPBM 26536, 2 (13.2, 13.3). Above 5 lots from vicinity of Mahe Island, just N. of Anonyme Island,~ 4.6°S, 55.5°E, 0–2.9 m, 10 February 1964, F-37, Böhlke et al.; ANSP 146511, 9 (8.4–14.2), 0–2.9 m, vicinity of Mahe Island, just N. of Anonyme Island,~ 4.6°S, 55.5°E, 0–2.9 m, 2 February 1964, F-17, Böhlke et al.; ANSP 146512, 1 (14.3), Mahe Island, Beau Vallon Bay, ~ 4.6°S, 55.4°E, 6.1–7.5 m, 15 March 1964, F-114, Dockins et al.; ANSP 146513, 2 (12.8, 12.9), Mahe Island, North West Bay, ~ 4.6°S, 55.5°N, 0–4.6 m, 9 February 1964, F-36, Böhlke et al.; ANSP 146514, 9 (7.7–13.9), Praslin Island., ~ 4.3°S, 55.7°E, 7.6 m, 22 February 1964, F-59; Böhlke et al.; ANSP 146508, 1 (11.1), Curieuse Island, ~ 4.2°S, 55.7°E, 11–15 m, 24 February 1964, F-66 Böhlke et al.; ANSP 146515, 1 (11.1), Amirante Islands, African Islands, South Island, ~ 4.8°S, 53.3°E, 0–4.6 m, 2 March 1964, F-75, Böhlke et al. MAURITIUS, Mascarene Islands, Cargados Carajos Shoals (also known as St. Brandon Rocks, St. Brandon Shoals on collection data), collected by V.G. Springer et al. in 1976. USNM 221753, 3 (14.3–15.2), Raphael Island, 16.4°S, 59.6°E, 5–9 m, VGS 76-20; USNM 221751, 15 (11.7–14.9), Raphael Island, 16.4°S, 59.6°E, to 3.7 m, 8 April 1976, VGS 76-12. CHAGOS ARCHIPELAGO (collected by R. Winterbottom and A. Emery in 1979). ROM 36420, 5 (11.7–14.4), Eagle Island, 6.33°S, 71.18°E, 0–. 5 m, WE 79-40; ROM 36419, 5 (11.9–14.2), Eagle Island, 6.33°S, 71.18°E, 0.5–2.0 m, WE 79-41; ROM 36418, 2 (13.3, 14.6), Peros Banhos, 5.44°S, 71.76°E, 3–7 m, WE 79-55; NMC 80-615, 2 (10.8, 13.4), Eagle Island, 6.33°S, 71.18°E, 0–. 75 m, WE 79-37; ROM 36417, 2 (14.6, 15.4), Peros Banhos, 5.44°S, 71.76°E, 7 m, WE 79-06; USNM 221744, 2 (12.6, 13.3), Salomon Island, 5.48°S, 72.38°E, 0–3 m, WE 79-82.

Non-types and questionable identifications: USNM 221750, 2 (10.6, 13.60), Cargados Carajos Shoals, 6–9 m, VGS 76-10. ANSP 146509, 1 (9.9), Amirantes Islands, 9 m, F-82.

Diagnosis. The following combination of characters distinguish E. notata from congeners: Nape with a series of three prominent dark transverse marks, the first two of which are separated into enlarged spots dorsolaterally; dorsal/anal fin-ray formula 7/7; cephalic sensory pore system complete; pectoral-fin rays 10–14 always branched; first dorsal fin not elongate.

Description. Dorsal-fin rays VI-I,6 (1), VI-I,7* (19); anal-fin rays I,6 (2), I,7* (18); pectoral-fin rays 14 (2), 15* (17), 16 (1), rays 10–14 branched; pelvic-fin rays I,4 plus a rudimentary 5th ray (7) or the 5th 1/10 th of the fourth (13); number of branches on the 4th pelvic-fin ray 5–14, average 9.2; number of segments between consecutive branches of the 4th pelvic-fin ray 0–4, average 1.1; pelvic-fin membrane reduced; branched caudal-fin rays 12 (1), 13 (2), 14* (5); segmented caudal-fin rays 17* (20); lateral scale rows 22 (1), 23* (16); transverse scale rows 5* (5); breast scaleless; precaudal vertebrate 10* (3) plus 16* (3) caudal, total 26*; spinous dorsal fin not elongate or filamentous; pelvic fins usually extend beyond origin of anal fin; cephalic sensory pore system pattern 1 (complete); male genital papilla not fimbriate.

Measurements (based on holotype and 9 paratypes, 12.6–15.4 mm. Values for the holotype first, followed in parentheses by the range of all types and the mean). Head length 31.7 (28.4–31.7, 29.6); origin of first dorsal fin 37.7 (33.2–39.3, 36.9); origin of second dorsal fin 59.3 (56.8–60.8, 58.2); origin of anal fin 59.3 (58.6–62.3, 60.1); caudal-peduncle length 26.1 (23.7–29.8, 26.2); caudal-peduncle depth 11.6 (10.1–12.0, 11.3); body depth 19.0 (16.2–19.0, 17.7); eye diameter 9.7 (9.1–10.9, 10.2); snout length 4.8 (3.8–4.8, 4.2); upper-jaw length 10.8 (8.1–11.1, 9.7).

Color of preserved specimens ( Figs. 1–3 ). The most prominent color marks are located on the head and nape, dorsally and dorsolaterally, and consist of a series of transverse marks, each composed of from 1–3 parts. The anteriormost transverse mark, immediately behind the eye, usually consists of a collection of moderately dark brown chromatophores. The following three transverse marks are the most prominent feature of this species’ color pattern: the first of these consists of two dark oval shaped patches, usually separated from each other at the midline but sometimes continuous; the next mark consists of three more or less circular spots arranged transversely, the two lateral spots intense dark brown, and the single spot along midline a less dense aggregate of chromatophores; the third prominent transverse mark usually is a continuous, weak to moderate bar, consisting of more loosely arranged chromatophores than the previous two marks, the bar sometimes divided into three parts as was the previous transverse mark; rarely, an additional very weak narrow bar just anterior to and touching the origin of the dorsal fin, which may be reduced to two weak aggregates of chromatophores on either side of the midline. Remainder of head with rather conspicuous scattered dark brown chromatophores, mainly on cheek but also present, though smaller and weaker, on opercle and snout.

Body with a series of up to ten spots along dorsal midline from origin of first dorsal fin to upper caudal-fin base, those on caudal peduncle weak or obscure except for the last, bordering the procurrent rays, which is well developed; spots merge into dark markings on the dorsal fins. Scale pockets outlined with dark chromatophores giving the appearance of a diamond pattern, most intense on upper body although sometimes obscure throughout. Body also with pale brown, uniformly scattered chromatophores, becoming faint in the upper anterior region of body. Five subcutaneous ventral midline spots and lower body bars from origin of anal fin to midcaudal peduncle where the fifth bar is integrated with an enlarged subcutaneous midcaudal peduncle spot; caudal peduncle spot variable in size and shape; upper portion of post-anal body with four subcutaneous bars, including the midcaudal peduncle bar, the third and fourth lower body bars merging into one, the third, upper body bar at the midline; a brown spot present at base of lower procurrent caudal-fin rays, similar to one on upper caudal peduncle. Three diffuse subcutaneous bars on belly anterior to origin of anal fin, the first two extending up to lateral midline from ventral region, but the third shorter, not extending to midline. Fleshy base of pectoral fin variable, many specimens with upper and lower weak clusters of chromatophores separated by a pale area in middle portion, others with diffusely scattered chromatophores on base, and in many specimens the upper and lower portions pale, with a cluster of chromatophores in midsection.

Degree of pigmentation of the first dorsal fin variable but a basic pattern persists: the minimal amount of pigmentation on the fin is in the form of three dark bars that extend diagonally from the lower, middle and outer portions of the first spine to corresponding dark spots on the midline of the body, this condition is commonly found in females. The first dorsal fin of males may appear as above, but usually is more fully pigmented: the pale band in the outer portion of the fin, as described above, is usually darkly pigmented but not always of the same intensity as the dark bars bordering it; the middle pale band may be fully or partly pigmented, as is the outer pale band, or, commonly, the fin is completely or nearly completely dark with the pale bands reduced to small areas corresponding in position to the pale areas between the midline body spots. Second dorsal and anal fins in both sexes moderately dusky, in females the second dorsal may be non-uniformly pigmented, the dark body spots extending somewhat into fins. Rays of pectoral and caudal fins finely marginated with chromatophores, the caudal fin somewhat darker, pelvic fins pale.

No sexual dichromatism other than that described above for the dorsal fins was noted.

Color of fresh specimen ( Fig. 4 ): Color of freshly collected paratype ROM 36417, 14.6 mm, male. Background color of head and body white, probably translucent when alive. Dark pigment pattern as described for preserved specimens. A yellow bar running from anteroventral portion of eye to under head. A second yellow area over the opercle, and a third on the upper portion of the pectoral-fin base. Sides of body with a slight yellowish tinge from anal-fin origin back to caudal-fin base. Pupil of eye sky blue, top of iris with two red spots. A reddish area on the posterior half of the upper jaw. Second dorsal, anal and caudal fins with a yellowish tinge overlaying a heavy peppering of dark chromatophores.

Distribution. Known from three island groups in the western and central Indian Ocean: the Seychelles and Amirante Islands; Mauritius, Mascarene Islands, Cargados Carajos Shoals; and the Chagos Archipelago.

Etymology. The specific epithet is from the Latin word nota meaning mark, in reference to the large, dark marks on the head and nape.

Comparison. Eviota notata belongs to the cephalic sensory-pore pattern 1 of Lachner and Karnella (1980). Eviota notata differs from all other species in this group by almost always having a dorsal/anal fin-ray formula of 7/7. The inclusion of E. notata brings the number of species in this group to 29.

Figures

FIGURE 1. Eviota notata, holotype, ANSP 145893, 13.4 mm male. Drawn by Jack R. Schroeder.

FIGURE 2. Eviota notata, holotype, ANSP 145893, 13.4 mm male. Dorsolateral view showing dark transverse marks on nape. Photograph by Kjell Sandred, Smithsonian Institution.

FIGURE 3. Eviota notata, paratype, USNM 221755, 13.7 mm gravid female. Photograph by Kjell Sandred, Smithsonian Institution.

FIGURE 4. Eviota notata, paratype, ROM 36417, 14.6 mm male. Photograph of freshly collected paratype by R. Winterbottom.