Eviota springeri, 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 : 71-73

Eviota springeri n. sp.

Springer’s Dwarfgoby ( Figs. 5–6 )

Holotype. USNM 222651, 14.2 mm male, Mauritius, Mascarene Islands, Cargados Carajos Shoals (also known as St. Brandon Rocks, St. Brandon Shoals on collection data), lagoon on west of Frigate Island, ~ 16.6°S, 59.5°E, depth 0-. 9 m, 1 April 1976, field number 76-4, Victor G. Springer.

Paratypes. MAURITIUS, Mascarene Islands, Cargados Carajos Shoals: USNM 222653, 3 (13.1–16.9), taken with holotype; USNM 222652, 1 (9.5), 16.53°S, 59.68°E, 0–2 m, 30 March 1976, VGS 76-1, Springer et al.; USNM 222656, 2 (7.3, 10.9), 16.6°S, 59.52°E, 15.2–21.3 m, 2 April 1976, VGS, Springer et al.; USNM 222655, 1 (13.1), S. Shoals, 16.75°S, 59.57°E, 15.2 m, 11 April 1976, VGS 76-18, Springer et al.; USNM 222657, 10 (11.1–13.4), Raphael Island, 16.4°S, 59.6°E, 0–9.1 m, 12 April 1976, VGS 76-20, Springer et al.; AMS I.22203- 0 0 1, 2 (11.9–15.3), taken with USNM 222657. Agalega Islands: USNM 222654, 1 (14.2), North Island, 10.32°S, 56.58°E, 0–18.3 m, 17 April, 1976, VGS 76-24, Springer et al.; BPBM 26539, 1 (14.0), taken with USNM 222654. SEYCHELLE ISLANDS: ANSP 145657, 1 (11.5), Faon Island, 4.6°S, 55.5°E, 12.2–15.2 m, 28 January 1964, F- 10, Dockins et al.; ANSP 145658, 8 (7.6–11.6), Faon Island, 4.6°S, 55.5°E, 10.7–13.7 m, 29 January 1964, F-11, Böhlke et al.; ANSP 145659, 2 (8.5,11.1), Mahe Island, 4.5°S, 55.5°E, 25.9 m, 15 February 1964, F-52, Dockins et al.; ANSP 145663, 1 (10.7), Mahe Island, Beau Vallon Bay, 4.6°S, 55.4°E, 6.1–7.6 m, 15 March 1964, F-114, Dockins et al.; ANSP 145664, 1 (12.0), Mahe Island, Beau Vallon Bay, 4.6°S, 55.4°E, 12.2–15.2 m, 19 March 1964, F-119, Böhlke et al.; ANSP 145660, 7 (9.1–13.6), Praslin Island, 4.3°S, 55.7°E, 12.2–15.2 m, 22 February 1964, F-61, Böhlke et al.; ANSP 145661, 4 (7.5–10.5), Curieuse Island, ~ 4.2°S, 55.7°E, 10.5–15 m, 24 February 1964, F66, Böhlke et al.; CAS 47915, 2 (12.1,12.6), taken with ANSP 145658. AMIRANTE ISLANDS: ANSP 145662, 2 (10.7,11.8), D’Arros Island, 5.41°S, 53.29°E, 21.3-27.4 m, 8 March 1964, F-103, Böhlke et al. CHAGOS ARCHIPELAGO: ROM 36650, 3 (11.5–12.6), Great Chagos Bank, middle of Three Brothers, 6.18°S, 72.0°E, 7 m, WE 79-43.

Diagnosis. A dark spot at anterior base of first dorsal fin and one medially at end of caudal peduncle; dorsal/ anal fin-ray formula 8/7; cephalic sensory pore system pattern 2, lacking the IT pore; pectoral-fin rays unbranched; first dorsal fin of male may be elongate; fifth pelvic-fin ray small, one-tenth to three-tenths length of fourth pelvicfin ray.

Description. Dorsal-fin rays VI-0,8 (1), VI-I,8* (19); anal-fin rays I,7* (20); pectoral-fin rays 15* (11), 16 (9), all unbranched; pelvic-fin rays I,4 plus a 5th that is 1/10th (17), 2/10ths* (1), or 3/10ths (1) of the 4th; branches on 4th pelvic-fin ray 4–6, average 4.6; segments between consecutive branches of the 4th pelvic-fin ray 2–6, average 3.1; pelvic-fin membrane well developed; branched caudal-fin rays 11* (8); segmented caudal-fin rays 16 (1), 17* (19); scales highly deciduous, lateral scale rows 21 (1), 22* (5); transverse scale rows 5* (3), 6 (1); breast scaleless; precaudal vertebrae 10 (12) plus 15* (12) caudal, total 25*.

Elongation of spinous dorsal fin uncommon; first and second spines in males may be filamentous, the first spine longest, extending at most to base of fourth ray of second dorsal fin; pelvic fins usually extend to origin of anal fin or beyond. Cephalic sensory pore system pattern 2, lacking the IT pore. Male genital papilla not fimbriate.

Measurements (based on holotype and 9 paratypes, 10.5–14.2 mm. Values for the holotype first, followed in parentheses by the range of all types and the mean). Head length 29.6 (29.6–33.0, 31.1); origin of first dorsal fin 35.2 (35.2–40.3, 37.5); origin of second dorsal fin 57.7 (54.8–60.2, 57.1); origin of anal fin 55.3 (55.1–60.3, 57.3); caudal-peduncle length 21.1 (21.1–27.1, 25.1); caudal-peduncle depth 12.7 (10.3–12.7, 11.4); body depth 21.8 (18.2–22.4, 20.5); eye diameter 9.9 (9.9–11.4, 10.8); snout length 4.2 (3.6–4.8, 4.2); upper-jaw length 11.3 (10.3–12.1, 11.2); pectoral-fin length 31.7 (27.1–39.7, 32.6); pelvic-fin length 31.0 (28.7–40.6, 33.2). Pectoral-fin length based on six individuals, pelvic-fin length based on five, maximum measurements probably closest to length in live individuals.

Color of preserved specimens ( Figs. 5–6 ). The outstanding color features are a dark blotch at anterior base of spinous dorsal fin, a dark spot on caudal peduncle over hypural plate, moderately pigmented scale pockets on body, usually some dark pigmentation bordering anal aperature, five subcutaneous ventral midline spots on body from origin of anal fin posteriorly, the five subcutanious bars ascending from these spots, the fifth bar with candelabralike branching at about midline.

Head dorsolaterally, including upper opercle, with brown pigmentation, some of which is arranged in patches behind the eyes, irregularly elsewhere on head and nape. A small dark spot near the upper preopercular pore. Some pigmentation on each side of snout between anterior and posterior nares; remainder of head pale. Upper portion of fleshy base of pectoral with large variously shaped patch of moderately intense brown chromatophores, faint or obscure in some, lower portion of base usually pale. Scale pockets on body with moderately developed pigmentation, usually more intense anteriorly and dorsolaterally. Up to eleven or twelve small dark spots along dorsal midline of body from origin of spinous dorsal fin to end of caudal peduncle, the last spot at base of procurrent rays, spots faded or obscure in some specimens. Anal aperature margined anteriorly with dark pigmentation in most specimens, some specimens with pigmentation completely encircling aperature and others with pigment absent or faded. A large prominent somewhat circular spot on caudal peduncle over the midportion of the hypural plate, spot slightly larger than pupil of eye; spot followed by a very narrow vertical dark bar at immediate base of caudal-fin rays, bar deeper than diameter of spot. Five moderately developed dark spots on ventral midline of body posterior to origin of anal fin; a smaller sixth spot, which may be faint or obscure, at ventral procurrent rays. Dark, rather wide subcutaneous bars ascending from first five spots to slightly above lateral midline of trunk, bars usually broader in upper portions; bars variously shaped but frequently with the second and third bars coalescing at about the midline, the fourth bar with or without branching at about the midline, and the fifth bar almost always multiply branched a little below midline, as in a tridentate candelabra. No subcutaneous bars dorsally on body and peduncle. Two to three diffuse faint subcutaneous patches anteriorly on body, most pronounced on belly.

First dorsal fin with dark blotch basally, most intense anteriorly, obscure or weakly developed in many specimens, outer portion of fin pale or light dusky; second dorsal fin dusky, slightly darker basally, weakly pigmented in some specimens; anal fin variably dusky, about equal in intensity to second dorsal fin, the tips of the rays may be paler. Caudal fin slightly dusky, less intense than second dorsal fin. Pectoral and pelvic fins pale.

The well-developed coloration described above applies to the larger males; females, smaller specimens and poorly preserved material have a reduced and/or faint spot on the first dorsal fin and at the end of the caudal peduncle, and the scale pigmentation is often weakly developed.

Distribution. Known from four widely distributed localities in the Indian Ocean, the Amirantes, Seychelles, Mauritius, and Chagos Archipelago.

Etymology. Named after Victor G. Springer, USNM, who collected a number of the type specimens of this species, as well as many valuable specimens of other Eviota species, thereby contributing greatly to our studies.

Comparisons. Eviota springeri belongs to cephalic sensory-pore pattern 2 of Lachner and Karnella (1980), lacking only the IT pore, has a dorsal/anal fin-ray formula of 8/7, simple pectoral-fin rays, and the 5th pelvic-fin ray one-tenth to three-tenths the length of the 4th pelvic-fin ray (usually one-tenth). The only other Eviota species in this group sharing these characters are E. nigrispina Greenfield & Suzuki , E. rubriceps Greenfield & Jewett , E. storthynx Rofen , and E. ancora Greenfield & Suzuki , all lacking the distinct dark spot at the midbase of the caudal fin present in E. springeri . In addition, E. nigrispina and E. rubriceps both have the scale pockets on the ventral half of the body darkly pigmented, whereas this is not the case in E. springeri . Eviota storthynx also has a dark postocular spot and the caudal fin crossed by dark pigment lines, and E. ancora has five irregular bands of circles of melanophores crossing the caudal fin, all characters lacking in E. springeri .

A single 10.3 mm specimen in poor condition (USNM 222658) from Sri Lanka might possibly be E. springeri .

Figures

FIGURE 5. Eviota springeri, holotype, USNM 222651, 14.2 mm male. Photograph by S. L. Jewett, Smithsonian Institution, NMNH, Division of Fishes.

FIGURE 6. Eviota springeri, paratypes, USNM 222653, 16.4 mm male. Photograph by S. L. Jewett, Smithsonian Institution, NMNH, Division of Fishes.