Gobius tetrophthalmus, Brito & Miller, 2001

Brito, A. & Miller, P. J., 2001, Gobiid ® shes from the Cape Verde Islands, including two new species of Gobius (Teleostei: Gobioidei), Journal of Natural History 35 (2), pp. 253-277 : 266-269

Gobius tetrophthalmus sp. nov.

( Figures 1D , 6 )

Material. HOLOTYPE:, l62.5 1 15.0 mm ( TFMC VP /441), Ilheu de Sal Rei , Ilha da Boa Vista, 7 October 98 ; PARATYPES: 3 mm, 26 1 6 and 35 1 9 mm ( TFMC VP/442 and VP/443), 48 1 12 mm ( BMNH), Ilha de Santa Luzia (Sur), 11 October 98; 2 ll, 40 1 10 ( TFMC) and 41 1 10 mm ( BMNH), Vila do Maio, Ilha de Maio ,

6 October 98. Also 2 ll, c. 48 1 13 and 50 1 12 mm, Baixo Joao Valiente,

10 November 1996.

Associated material. Bathygobius casamancus : see Miller and Smith (1989) and above; Gobius rubropunctatus and G. senegambiensis : listed above for G. ateriformis .

Generic identi W cation. The present new species has all the diagnostic characters of Gobius as noted above for G. ateriformis .

Speci W c identi W cation. By the possession of (i) divided row d; (ii) about 50 or more scales in lateral series; (iii) complete pelvic disc; (iv) nasal tentacle simple; and (v) pore a at rear of orbit, G. tetrophthalmus resembles G. buchichii Steindachner among temperate Eastern Atlantic species but di OEers from the latter in coloration, with longitudinal banding of the head and vertical dark banding of body rather than the longitudinal series of dark spots on head and body of G. buchichii ( Miller, 1986) . As noted above for G. ateriformis , the tropical G. senegambiensis and

G. rubropunctatus diOEer from G. tetrophthalmus in the presence of (i) a complete row d; and (ii) a wider gap between pores R and R 1 in the posterior oculoscapular groove. In coloration, G. rubropunctatus has a spotted head and body with a conspicuous blotch in the upper anterior corner of the ®rst dorsal ®n. Material of G. senegambiensis does not display the longitudinal striping so evident in G. tetrophthalmus .

The striped head of G. tetrophthalmus is very reminiscent of the coloration of Bathygobius casamancus , a species also present at the Cape Verdes ( Miller and Smith, 1989; see above). However, on more careful examination, basic di OEerences in pattern of striping are easily noted. In particular, longitudinal stripes end posteriorly opposite the ®rst dorsal base in G. tetrophthalmus while in B. casamancus the body displays longitudinal bands to the origin of the caudal ®n ( Miller and Smith, 1989, ®gure 9, plate II). Apart from coloration, B. casamancus has only longitudinal

rows of cheek papillae in contrast to the transverse arrangement in Gobius .

Name. The new species is named for the impression of four eyes when the living specimen is viewed from above, the pale ocellus in the dark band crossing the upper border of each eye lying median to the dark pupil and pale sclera of the eye itself (®gure 1D). This feature may become obscured in preserved material (®gure 6).

General description. See features noted under Generic and Speci W c identi W cation. Body proportions as table 6. Anterior nostril with single triangular or more elongate tentacle, posterior nostril pore-like, with slightly raised edges (®gure 7B). Angle of jaws below anterior edge of pupil; upper lip width equal to or slightly narrower than preorbital width. Teeth caniniform, in three or four rows medially with outer and inner somewhat enlarged.

Fins. D1 VI (6:8); D2 I /13 (12±13; 12:1,13:6); A I /12 (12:6); C 17 articulated; P 21 (20±22; 20:1,21:7,22:3); V I /5 1 I/5. Fin-bases or lengths as table 1; tips of D1 II to D2 I/1, IV and V to D2 /3, and VI to D2 1 /2 when depressed; interdorsal space about ®ve-sixths membranous; D2 rear tip to opposite upper origin or proximal part of C, A rear tip to opposite lower origin of C; P with bi®d upper three rays and tip of fourth free from membrane (®gure 7A); V disc elliptical, with well developed anterior membrane, lacking lateral lobes, and rear edge slightly emarginate, ®fth ray slightly shorter than fourth (®gure 7C); C rear edge rounded.

Scales. Body with ctenoid scales; in lateral series 49±54 (49:1,50:1,51: 1,52:3,53:3;54:1), in transverse series 13±17; predorsal in median line 16±21. Head,

predorsal area (forward of line from upper origin of P to D1 origin) and nape scaled to opposite pore v, 21 in median line from origin of D1; opercle and cheek naked; breast scaled completely, about eight to 11 in median line.

Coloration (®gures 1D, 6). Body pale brown with several dark brown blotches interspersed with pale saddles along dorsal midline, variously sized dark blotches

along lateral midline; ®ne horizontal striae sometimes evident along the body. Breast, underside of body with ®ne dark reticulation, lacking paired abdominal spots. Nape with conspicuous longitudinal dark bands, a median pair from dark blotch on upper border of eye, fading lateral to base of ®rst dorsal ®n, and more lateral band along oculoscapular groove from eye to above pectoral ®n base. Eye blotch encloses more or less distinct pale ocellus. Snout with antrorse V-like dark mark. Cheek and opercle with two dark horizontal bands, upper from jaw and lower along lower border of cheek from behind jaw angle, meeting prominent dark spots on pectoral base, upper P spot more intense. Chin with dark transverse band, and branchiostegal membrane densely stippled. Median ®ns and P dusky, denser at edge; D1 darker proximally, with upper pale band, D2 similar, with three proximal horizontal dark bands, and C with darker lower border; A without basal dark dots. V stippled. Lateral-line system (®gure 8). Head canals and pores as Generic identi W cation. Rows and number of free neuromast organs (sensory papillae) from holotype and two paratypes (SL 48.0± 62.5 mm): Anterior lateral-line innervation: (i) supraorbital: dorsal n (5±11), o (5±9); rostral s 1 (5±6), s 2 (4±5); (ii) infraorbital transverse 1 (14±19), 2 (8±12), 3 (8±11), 5s 1 5i (5±8 1 4±9), 6s 1 6i (4±11 1 7±12); caudal fork

s 3 (3±5), r1 (2±4), r2 (2±3); rostral fork c 1 (5±10), c 2 (3±6), c (5±7), c (9±16); 1 2

(iii) hyomandibular longitudinal z (4±6), i (34±45); median mandibular b (16±23) and d (26±34); ventral mandibular e (53±84); rostral mandibular f (7±12); ventral opercular ot (26±35) and oi (8±9); dorsal opercular os (10±15); (iv) otic tra (1). Posterior lateral-line innervation: (i) supratemporal otic u (1); transverse q (3±4); accessory x 1 (16±20), x 2 (7±10), g (5±10), m (5,7); (ii) posterior lateral primary la 1 (6±10), la 2 (9±12), ltm (transverse rows, each of several papillae, along lateral midline to C origin, not proliferated), and trunk h (16±20), as 1 (13), as 2 (4±6), as 3 (4±5) and lc (three rows along C rays).

Biology. Distribution. Recorded to date only from the Cape Verde archipelago, around which the species appears to be widespread, having been collected at the islands of Santa Luzia, Boa Vista, B. de Joa Äo Valente, and Maio, and observed at SaÄo Nicolau, Sal, and Santo AntaÄo (®gure 9). Habitat. Found at 7±25 m, most commonly on mixed coralline algae (maerl), but also on open sand and rock substrata, often with Gnatholepis thompsoni . Biology otherwise not investigated .

Figures

FIG. 1. Didogobius kochi, dark phase; (B) D. kochi, paler phase retaining prominent anterior vertical dark band; (C) Gobius ateriformis sp. nov.; (D) Gobius tetrophthalmus sp. nov. All from Ilheu do Sal Rei, Boa Vista.

FIG. 6. Gobius tetrophthalmus sp. nov., holotype, male, 62.5 1 15.0mm (TFMC), Ilheu de Sal Rei, Boa Vista, in (A) lateral, (B) dorsal, and (C) ventral views.