Mauligobius nigri (GuÈnther, 1861)

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 : 270-274

Mauligobius nigri (GuÈnther, 1861)

( Figure 2C )

Material. Cape Verdes: l 40 1 10 mm, m 70 1 16 mm, and juvenile, 29.5 1 6.2 mm, Ilha de SaÄo Tiago, U. Schliewen.

Associated material.` Niger Expedition’ : HOLOTYPE, 1, l54 1 12.5 mm ( BMNH 1847.4.4), don. L. Fraser.

Generic identi W cation. The present material shares with the type species of Mauligobius , M. maderensis (Valenciennes) , the generic characters of (i) anterior and posterior oculoscapular and preopercular head canals, with pores S, l, K, v, a, B, R; R 1, R 2, and x, d, E, respectively; (ii) seven transverse infraorbital rows (1±7), with inferior sections of 5 and 6 well developed below hyomandibular row b; (iii) anterior dorsal row o with few papillae and well separated from fellow in dorsal midline; (iii) row g ending behind row o; (iv) upper rays of pectoral ®n multi®d and free from membrane; (vi) anterior nostril rim with dermal process; (vii) head scaled, including rear cheek; (vii) pelvic disc anterior membrane with pronounced lateral lobes.

Speci W c identi W cation. This species is very easily distinguished from M. maderensis by (i) extreme proliferation of free pectoral rays; (ii) greater extent of cheek scaling; (iii) short extension of AOS below orbit with extra papilla in largest ®sh; (iv) pattern of infraorbital transverse sensory papillae rows, with juxtaposition of rows 4 and 3; (v) transverse alignment of hyomandibular rostral (mental) row f, (v) anterior nostril with much divided rim process; (vi) ®n ray counts of D2 I /10, A I/8±9, and P 24±26, in contrast to D2 I /13±14, A I/11±12 and P 18±20 for M. maderensis ; and (vii) 40±45 scales in lateral series, against 53±55 (48±57) for M. maderensis . Miller (1984) suggested that Gobius macrophthalmus Osorio, 1911 , from the Cape Verdes, is a junior synonym.

General description. Morphometrics as table 3; note that anal ®n base is shorter than caudal peduncle, a feature usually seen among sleeper gobioids. Otherwise as Generic and Speci W c identi W cation; anterior nostril with rim process divided into several tentacles (®gure 10B);

Fins. D1 VI (VI: 3); D2 I /10 (10:3); A I /8±9 (8:1, 9:1); C 17 articulated; P 24±26 (24:1,25:3,26:2); V I /5 1 I/5. Fin-bases or lengths as table 3; tips of D1 rays

not extending to D2 when depressed; interdorsal space mostly membranous; D2 rear tip about three-quarters of distance to upper origin of C, A rear tip half distance to lower origin of C; P with upper nine rays multi®d and free from membrane, their bases ¯attened and overlapping and each ray divided from near base into about a dozen branches (®gure 10A); V disc rounded, with deep anterior membrane having pronounced lateral lobes, about half width of former, and stout articulated rays much branched (®gure 10C); C rear edge rounded.

Scales. Body with ctenoid scales; in lateral series 40±46 (40: 1,42:1, 43: 2; 44:1; 46:1), in transverse series 15±17; predorsal in median line 18±22 to pore K. Head,

predorsal area (forward of line from upper origin of P to D1 origin) and nape scaled to rear interorbit (pore K) and several more anterior scales into interorbit and rear snout; opercle and cheek scaled, latter to below anterior half of eye, several rows deep from eye to row d; breast scaled completely, about ten to 12 in median line; scales extending onto base of pectoral ®n.

Coloration. Preserved (®gure 2C), body dark, with about a dozen small darker spots along lateral midline but lacking vertical dark bars; head with dark mottling;

®rst and second dorsal ®ns with two or three oblique rows of small white spots; pelvic disc paler than other ®ns.

Lateral-line system (®gure 11). The condition of the holotype did not permit a description of the head lateral-line system ( Miller, 1984) but present material is su ciently well preserved for all diagnostic features to be investigated. Head

with anterior and posterior oculoscapular and preopercular canals, with pores S, l, K, v, a, B, R; R 1, R 2, and x, d, E, respectively. Anterior oculoscapular canal opening at short infraorbital extension, pore S present in largest specimen; Pores R and R 1 contiguous, without intervening papillae. Rows and number of free neuromast organs (sensory papillae) from largest example (SL 70.0 mm), left /right: Anterior lateral-line innervation: (i) supraorbital: dorsal n not evident, o (7/7); rostral s 1 (8,9), s 2 (20,15); (ii) infraorbital transverse 1 and rostral fork c 1, c (,), c form belt of

2 1

papillae in lateral preorbit (63,59), 2 (30,24), 3 (10,13), 4 (15,15); 5s long, to near level of row d (21,20), 5i (14,13), 6s (20,19), 6i (20,14); caudal fork s 3 (8,7), r 1 and r 2 (9,9); rostral fork c 2 (5,7); (iii) hyomandibular longitudinal z (7,7), i (c. 85); median mandibular b (25/24) and d (35,30); ventral mandibular e (c.70); rostral mandibular f transverse, continuous (about 30); ventral opercular ot (50/48) and oi (19,15); dorsal opercular os (22,24). Posterior lateral-line innervation: accessory x 1

(9,12), x 2 (5,3), g (7,7), m (5,5); (ii) posterior lateral la 1 (,), ltm (transverse rows,

each of several papillae, along lateral midline to C origin, not proliferated), and trunk h (,), as 1 (,), as 2 (,), as 3 (,) and lc (three rows along C rays). This species appears to be the only representative among the eastern Atlantic±Mediterranean Mauligobius ± Gobius ±Neogobius clade to possess a transverse row f, otherwise found among many Indo±West Paci®c taxa with longitudinal infraorbital rows, a feature which must be regarded as of independent origin in M. nigri .

Biology. Distribution. The new Cape Verdes material is from San Tiago while Osorio’ s was from Ilheu Raso. The provenance of the holotype, originally given as` Niger’ by Gu Ènther (1861), was discussed by Miller (1984): the Niger expedition of 1841 collected ®sh from the Cape Verdes to Annobon, including the Niger and

Cameroon estuaries and Fernando Po ( Allen and Thomas, 1848). Boulenger (1905) records the species from the mouth of the Rio Benito but the dearth of recent records from elsewhere in West Africa might indicate restriction to the Cape Verdes. Habitat. The largest specimen in the present material was collected in shallow water (less than 50 cm) among large lava-pebbles under strong wave action, while the two smaller examples came from a boundary area between rocks and sand at 2±4 m depth (U. Schliewen, personal communication). The former record supports the suggestion by Miller (1984) that the species is marine and lives in a high energy environment. The short, rounded pelvic disc, with much rami®ed articulated rays, is also seen in freshwater gobies inhabiting fast ¯owing streams, such as Asiatic Rhinogobius species ( Chen et al., 1999) and the sicydiines ( Parenti and Maciolek, 1993). Size. The maximum recorded now is a total length of 86 mm comparable to

that of 87 mm recorded by Osorio (1911).

Figures

FIG. 2. (A) Gnatholepis thompsoni, male, 43.01 13.0mm, SaÄo Vicente; (B) Gobius ateriformis sp. nov., holotype, male, 55.0 1 12.0mm (BMNH), SaÄo Tiago; (C) Mauligobius nigri, female, 70.0 1 16.0mm, SaÄo Tiago.