Comprehensive Description
provided by Smithsonian Contributions to Zoology
Eviota bifasciata
MATERIAL EXAMINED.—158 specimens from 8 localities totaling 69 males, 50 females, and 39 juveniles; total size range 7.6–22.5; largest male 22.5, largest female 17.7; smallest gravid female 12.6.
Holotype: USNM 219276 (22.5), male; Philippine Islands, Palawan Province, Bararin I., 23 May 1978, Smithsonian team, SP78–20.
Paratypes: PHILIPPINE ISLANDS: USNM 219272, 4 (15.3–21.8), 3 males (21.8), 1 female (15.3); same data as holotype. JAVA SEA: AMS I.20794–001, 2 (21.5, 22.3), males; Bawean I. or Pulau Seribus (collections mixed), Mar-Apr 1974, V. G. Springer. KARIMUNDJAWA ISLANDS (collected by V. G. Springer in 1974); USNM 219277, 1 (15.8), female; 29 Mar, VGS 74–28. USNM 219275, 14 (14.1–17.9), 4 males (17.9), 10 females (16.8); 30 Mar, VGS 74–30. MOLUCCAS: (collected by V. G. Springer in 1973): USNM 210148, 1 (12.7), male; Saparua, 17 Jan, VGS 73–12,Rumphius Exp. 1, sta IP–1. USNM 210248, 5 (7.6–10.7), juv.; Ambon I.,8 Jan, VGS 73–4, Rumphius Exp. 1, sta MO-2. USNM 209638, 14 (10.7–18.7), 3 juv., 8 males (18.7), 3 females (12.9); Ceram, 10 Jan, VGS 73–6, Rumphius Exp. 1, sta Li-1. ANSP 141129, 2 (10.1, 13.5), 1 juv., 1 male (13.5); Ceram, 10Jan, VGS 737, Rumphius Exp. 1, sta Li-1. CAS 43547, 8 (10.6–14.7), 4 juv., 1 male (14.7), 3 females (13.0); Ceram, 9 Jan, VGS 735,Rumphius Exp. 1, sta Pi-1. PAPUA NEW GUINEA: USNM 219273, 18 (12.1–17.4), 13 males (17.4), 5 females (14.7); Madang Harbor, 30 May 1970, B. B. Collette, 1495. AMS I.20800-001, 6 (13.5–16.1), 3 males (16.1), 3 females (14.7); same data as above.USNM 219669, 12 (9.7–18.4), 2 juv., 6 males (18.4), 4 females (15.4); Kranket Is., 7 Nov 1978, V. G. Springer, 78–23. USNM 219668, 65 (7.6–21.8), 22 juv., 24 males (21.8), 19 females (17.6); Hermit Is., 1 Nov 1978, V. G. Springer, 78–13. USNM 219670, 2 (16.2, 17.2), males; Hermit Is., 2 Nov 1978, V. G. Springer, 78–16.
Other Material: PALAU ISLANDS: CAS 43789, 1 (10.2), juv., Iwayama Bay, 18 Nov 1957, DeWitt, sta 57–59, GVF Reg. 1439. CELEBES: USNM 219278, 1 (10.8), juv., Kabaena I., 24 Feb 1974, V. G. Springer, 74–1. BORNEO: USNM 219274, 1 (17.7), female; Pulau Gaya, Darvel Bay, 1 Feb 1965, Cohen and Davis, Te Vega cr. 6, sta 213.
DIAGNOSIS.—Pectoral fin rays simple; spinous dorsal fin elongate or filamentous in both sexes, the second to fourth spines longest; fifth pelvic fin ray well developed, six-tenths to eight-tenths length of fourth ray; cephalic sensory pore system lacking the IT and the PITO pores, and the AITO pore may be single or double; posterior rays of second dorsal and anal fins elongate; central rays of caudal fin may be elongate, forming a lanceolate fin; basal portion of second dorsal and anal fins and membrane of elongate rays brown to black; upper and lower posterior portion of caudal peduncle and caudal fin with black streaks.
DESCRIPTION.—Dorsal fin VI-I,8(1), VI-1,9-(27), VI-I,10(3); anal fin I,8(9), I,9(19), I,10(1); pectoral fin 14(4), 15(22), 16(5); pelvic fin I,4 6/ 10(9), I,4 7/10(14), I,4 8/10(2); fourth ray of pelvic fin with 2–5 branches, averaging 3.2; segments between consecutive branches of the fourth pelvic fin ray number 4–10, averaging 6.1; pelvic fin membrane well developed; branched caudal fin rays 8(1), 10(1), 11(11), 12(2); segmented caudal fin rays 17(29); lateral scale rows 22(8); transverse scale rows 6(2), 7(5); scales with 28–32 ctenii, 9–10 primary radii, 1–2 secondary radii; breast usually scaled.
The cephalic sensory pore system is pattern 3, except that 11 of 30 specimens have a double bilateral AITO pore. The cutaneous papilla system is pattern B, as described for Eviota lachdeberei.
The first five dorsal spines elongate or filamentous in males, the second, third or fourth may be longest, the longest filament extending to beyond end of base of second dorsal fin, the fifth and sixth spines may be slightly elongate in some specimens; dorsal spine elongation reduced in females, found only in the first three spines, the second may be filamentous, extending at most to base of third ray of second dorsal fin; the pelvic fin commonly extends beyond origin of anal fin, but shorter in some specimens.
Genital papilla in male not fimbriate, long and slender, slightly bilobed at tip, its maximum length to base of third anal fin ray; female papilla short, bulbous, with 2–3 fingerlike projections at each side of tip, and extends to anal spine.
Gravid females range in size from 12.6–17.7 mm SL.
Vertebrae 10(9) precaudal and 14(1), 15(8) caudal, total 24(1), 25(8).
COLOR IN PRESERVATION.—Chin black; snout blackish, pigmentation extending to interorbital area; a small dark, mostly subcutaneous spot, smaller than pupil, beneath upper preopercular pore; cheek and opercle with uniformly scattered chromatophores, often faded or pale; some scattered chromatophores on occiput on each side of midline, rest of nape mostly pale; base of pectoral fin with a dark spot on upper portion, sometimes deep, with weak extension onto lower base, spot often diffuse; scales margined with single rows of chromatophores, more developed on lower half of trunk; spinous dorsal fin finely dusky, larger specimens with a narrow dark band basally; ends of filmanentous spines may be tipped with brown; basal third of second dorsal fin dark brown, the posterior elongate portion brownish black to distal margin, the outer anterior portion of the fin pale to dusky; basal third of anal fin dark brown, elongate posterior portion brownish black, outer anterior portion pale to dusky; the longest portions of the second dorsal and anal fins are also the darkest; end of upper portion of caudal peduncle, in the region at the procurrent rays, and upper part of caudal fin with dark brown streak extending about halfway out the length of caudal fin; a similar but darker streak on lower part of caudal peduncle, along ventral midline posterior to anal fin, and extending halfway out the lower part of caudal fin as a streak; the lower streak is widest at the lower part of hypural base, where it occupies about a fourth to a third the height of the caudal peduncle, and tapers caudad as it extends out the caudal fin; tips of lower procurrent rays excluded from dark streak; basal third of central area of caudal fin pale, remainder of fin finely dusky; pectoral fins pale; pelvic fins pale to finely dusky in larger specimens. No ventral midline spots or subcutaneous bars.
The color pattern is weaker and not as extensively developed in females or juveniles, compared to the larger males. In females, the spot on the preopercle often weak or obscure; spot on upper pectoral base greatly reduced and of weaker intensity; dark streak on upper part of caudal peduncle and caudal fin greatly reduced and faint; streak on lower part of peduncle and fin somewhat reduced; pigmentation of dorsal and anal fins reduced and, in smaller specimens, fins nearly pale; pigmentation outlining scales much reduced.
GEOGRAPHIC DISTRIBUTION.—Restricted to the Philippine Islands, Indonesia, Papua New Guinea, and Palau Islands. Known from seven localities: the Java Sea; Kabaena Island, lower Celebes; Darvel Bay, northeast Borneo; Palawan Province, P.I.; Ceram and Saparua; Iwayama Bay, Palau Islands; Madang Harbor, Papua New Guinea (Figure 64).
ETYMOLOGY.—The specific name bifasciata, derived from the Latin, is in reference to the upper and lower dark streaks on the caudal peduncle and caudal fin.
- bibliographic citation
- Lachner, Ernest A. and Karnella, Susan J. 1980. "Fishes of the Indo-Pacific genus Eviota with descriptions of eight new species (Teleostei, Gobiidae)." Smithsonian Contributions to Zoology. 1-127. https://doi.org/10.5479/si.00810282.315
