Parananochromis brevirostris, Anton Lamboj & Melanie L. J. Stiassny, 2003

Anton Lamboj & Melanie L. J. Stiassny, 2003, Three new Parananochromis species (Teleostei, Cichlidae) from Gabon and Cameroon, Central Africa., Zootaxa 209, pp. 1-19 : 7-12

Parananochromis brevirostris , new species

(Figs. 4-9)

Nanochromis cf. dimidiatus - Géry, 1965: 381

Parananochromis sp. “Makokou” - Lamboj, 1999a: 126; Linke & Staeck, 2002: 151.

Holotype. AMNH 232536, male, 42.5 mm SL; Gabon: Ivindo system, Small, shallow creek ca. 200m downstream of IRET station (on opposite side of river), 0°30´34”N, 12°48´33” E, M.L.J. Stiassny & E. Vreven, Jan 1998.

Paratypes. Total of 57 specimens, 21.2-51.2 mm SL, AMNH 230720, 15 males, 6 females, 2 undet. 31.4-42.2 mm SL, Gabon: Ivindo system, Small creek ca. 200m downstream of IRET station (on opposite side of river), 0°30´34”N, 12°48´33” E, M.L.J. Stiassny & E. Vreven, Jan 1998. - AMNH 230707, 4 undet, cleared and stained, 32.0-41.2 mm SL, Gabon: Ivindo system, small creek mouth emptying into Ivindo River, across from IRET field station, 0°30’15.4”N, 12°48’52.4”E, M.L.J. Stiassny et al., Jan. 1998. - MRAC 73-02-P-2147-150, 1 male, 2 females, 1 undet., 21.2-47.4 mm SL, Gabon: Ivindo system, route Makokou-Loloa, 3rd marigot, D.F.E.Thys van den Audenaerde, Nov 1964. - MRAC 93-085-P-0334-0340, 3 males, 4 females, 30.0-45.4 mm SL, Cameroon: Ntem system, riv. Lé, downstream of Abang-Minkoo, 2°20´N, 11°26´E, A. Kamden, May 1993. - MRAC A2-11-P-15, 1 male, 46.2 mm SL, Gabon: Ivindo system, tributary of riv. Aboy, route Makokou-Okondja, 0° 32´N, 12°56´E, A. Lamboj, R. Guggenbühl, P. Sewer & A. Weissenbacher, Jul 1995. - MRAC A2-11-P-16, 1 female, 33.0 mm SL, Gabon: Ivindo system, little creek on route Makokou-Ovan, 7km from Makokou, 0°34´N, 12°45´E, A. Lamboj, R. Guggenbühl, P. Sewer & A. Weissenbacher, Jul 1995. - MRAC A2-11-P-17, 1 undet., 37.8 mm SL, Gabon: Ivindo system, Ngong-Bissoga, route Makokou-Ovan, at village Adoue, 0°31´N, 12°33´E, A. Lamboj, R. Guggenbühl, P. Sewer & A. Weissenbacher, Jul 1995. - MRAC A2-011-P-18, 1 male, 51.2 mm SL, Gabon: Ivindo system, tributary of riv. Aboy, route Makokou-Okondja, 0° 32´N, 12°56´E, A. Lamboj, R. Guggenbühl, P. Sewer & A. Weissenbacher, Jul 1995. - BMNH 2002.8.8.4-6, 2 males, 1 undet., 38.4-48.6 mm SL, Gabon: Ivindo system, tributary of riv. Aboy, route Makokou-Okondja, 0° 32´N, 12°56´E, A. Lamboj, R. Guggenbühl, P. Sewer & A. Weissenbacher, Jul 1995. - NMW 94630, 3 females, 31.6-49.8 mm SL, Gabon: Ivindo system, riv. Zaidie, on bridge of road Makokou-La Scierie-Belinga, 0°44´N, 13°09´E, A. Lamboj, R. Guggenbühl, P. Sewer & A. Weissenbacher, Jul 1995. - MHNG 2640.27, 1 male, 1 undet, 29.4-40.9 mm SL, Djaddie system, marigot in the Djaddie, Mekambo, J.Gery, Aug 1964. - MHNG 2640.28, 2 undet. 31.9-37.9 mm SL, Marigot, Djaddie at Mekambo, J.Gery, Aug 1964. - CU 87042, 2 males, 3 females, 33.2-40.4 mm SL, Gabon: Ivindo system, Small creek ca. 200m downstream of IRET station (on opposite side of river), 0°30´34”N, 12°48´33” E, M.L.J. Stiassny & E. Vreven, Jan. 1998.

Differential Diagnosis. Parananochromis brevirostris is unique among congeners in the absence of scales on the chest and weakly developed, or absent, pharyngeal hanging pad. It is also readily distinguished from all congeners except P. ornatus by the possession of 4 (versus 5) infraorbital bones.

Description. Measurements and meristic counts for holotype and 50 paratypes are given in Table 2.

This is a diminutive species, the largest specimen is a mature male (51.2 mm SL), and the largest female is 38.2 mm SL with ripening eggs in its ovaries. Sexual dimorphism is well developed. Males are usually 20-30 % larger than females, with soft dorsal and anal fin rays more produced. The first ray of pelvic fin is usually the longest in the fin of both sexes, and is produced in males; in females the second ray may occasionally be slightly longer than first. The tips of pelvic fins in large males usually reach the anus. Lappets of spiny dorsal fin are elongated and pronounced, particularly so in males. The caudal fin is rounded in both sexes. Snout is short and rounded (length 19.2-31.3% HL), and the body gracile even in the largest specimens (depth 22.7-31.6% SL).

Osteology and dentition. Infraorbital series (Fig. 2b) with a plate-like first infraorbital followed by three 3 tubular elements. There is a large gap between the third infraorbital and a small fourth infraorbital. Infraorbital 1 with four openings of the laterosensory system. Usually 25 vertebrae, 12 precaudal and 13 caudal (26 vertebrae, 12 precaudal and 14 caudal in two individuals). Premaxilla and dentary with (2) 3-5 rows of numerous, acutely cusped, unicuspid teeth with little size difference between the teeth of inner and outer rows (Fig. 5). Lower pharyngeal bone narrowly triangular, with numerous, slender, shouldered unicuspid teeth on lateral parts of the bone and larger asymmetric bicuspid teeth in the central field.

Gill rakers on first gill arch. Lower limb with 5-8 tuberculate gill rakers, 2-4 pointed gill rakers on the epibranchial. No microbranchiospines are present. The hanging pad on roof of the pharynx is poorly developed or absent.

Squamation. Cycloid, cheek usually naked, occasionally with a single scale row, 3-4 horizontal scale rows on the opercle. Dark spot on outer edge of opercle is unscaled. Chest is naked. Upper lateral line is separated from dorsal-fin base at its highest point (8th pored scale) by 1-1½ scales, at last pored scale by 0-½ scales. No overlap between the end of the upper lateral line and the lower lateral line. Caudal fin scaled basally for about one third of its length; the other fins are unscaled.

Coloration. Living specimens (Figs. 6-9): Base body coloration is grey to light brown, darker dorsally than ventrally. Dark spot on the outer edge of opercle is extended anteriorly and posteriorly into a midlateral stripe. In males the soft dorsal fin and upper margin of the caudal fin have a narrow white border, in females these borders are red. In both sexes these fins have a thin black submarginal band. Soft-dorsal, caudal and posterior parts of the soft-anal fins in both sexes are clear or grey, with rows of dark maculae, which are always more marked in males than in females - females sometimes with immaculate fins. Anterior parts of the anal fin are violet to wine red in males and pale yellow or clear in females. Males with reddish coloration in the lower lobe of the caudal fin. Pelvic fins are pale yellow to reddish, with a dark anterior leading edge; all colorations are more marked in males than in females. Pectoral fins are clear. Sometimes a dark horizontal stripe is visible, passing from the snout through the eye, and extending onto the first third of the caudal fin. Occasionally this stripe is replaced by a row of black spots or blotches. Wellmarked interorbital, nostril, and lachrymal stripes are present on the head. Ripe females have a rosy to orange or violet belly. Lips are light grey to light brown. Body scales with dark margins on the whole body in males, in females such markings are restricted to the dorsal parts of the body.

Preserved specimens (Fig. 4): Coloration of the head and body are brown, with the upper half darker than the ventral parts. A dark, midlateral stripe, is continuous from the eye (merging with the dark opercular spot) and extending onto the first third of the caudal fin. Unpaired fins are dusky grey or brownish. The soft-dorsal, soft-anal, and caudal fin membranes have rows of dark maculae.

Breeding behaviour. In aquaria a pair-bonding, cave-breeding species. For further information on breeding biology see Lamboj, (1999a, as Parananochromis sp. “Makokou” ).

Distribution (Fig. 3). Currently the species is known from scattered localities in the Ivindo and Ntem systems in eastern Gabon and southeastern Cameroon, and from the Ogowe system in the region of Ndjole in Western Gabon.

Etymology. From the Latin brevis, short and rostrum, beak or snout, in reference to the short, rounded snout of the species.

Remarks. This diminutive species is found in abundance in the many small forest creeks and streams (marigots) of the Ivindo River system and is also recorded from the River Lé, a small affluent of the Ntem in similar habitats. Specimens from the Menguengne River (Ogowe system) near the town of Ndjole in western Gabon have been collected and raised in aquaria (Figs 7,9), but not yet preserved. Individuals from the vicinity of Makokou were misidentified by Géry (1965) as Nanochromis cf. dimidiatus .