Parananochromis axelrodi, 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 : 3-7

Parananochromis axelrodi , new species

(Fig. 1)

Holotype. AMNH 230714, male, 79.2 mm SL; Gabon: Ivindo system; mouth of Bale creek into Ivindo. Just inside mouth of Bale creek in forest, 0°30´53.9”N, 12°48´21.2”E, J.P. Sullivan et al., Jan 1998.

Paratypes. Total of 8 specimens, 25.6-91.2 mm SL; AMNH 233351, 1 undet., 25.6 mm SL; Gabon: Ivindo River system, lower Bale creek, 0°30´57”N, 12°48´17.8”E, M.L.J. Stiassny et al., Jan 1998. - AMNH 230665, 1 male, 53.7 mm SL; Gabon: Ivindo system; gill net across mouth of Bale creek into Ivindo, 0°30´54.5”N, 12°48´20.5”E, E. Vreven and C. Hopkins., Jan 1998. - CU 87044, 1 undet., 35.0 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. - AMNH 233350, 3 undet., 25.7-51.0 mm SL, 1 spec. 51.0 mm SL cleared and stained, Gabon: Ivindo system, small creek about 200 m downstream of IRET field station (on opposite side of river), 0°30´34”N, 12°48´33”E, M.L.J.Stiassny and E. Vreven., Feb. 1998. - MRAC-A2-046-P- 1, 1 male, 49.5 mm SL, Gabon: Ivindo system, small creek about 200 m downstream of IRET field station (on opposite side of river), 0°30´34”N, 12°48´33”E, M.L.J.Stiassny and E. Vreven, Feb. 1998. - MHNG 2203.047, 1 male, 91.2 mm SL, Gabon: Ivindo system, Bras mort of the Djouah, upstream of Mvaddi, J. Géry, Sept. 1964.

Differential Diagnosis. Parananochromis axelrodi is readily distinguished from P.brevirostris and P. ornatus by the possession of 4 (versus 3) tubular infraorbital bones and a total of 15-18 gill rakers on the outer row of the first gill arch (versus 8-12 in P. brevirostis and 10-13 in P. ornatus ), from P. caudifasciatus and P. gabonicus by number of gill rakers along outer row of first gill arch (15-18 versus 10-14 in P. caudifasciatus and 11-14 in P. gabonicus ), and by its deep-body (BD 35.4-42.2% SL versus 27.0-36.0% in P. gabonicus and 29.7-36.2% in P.caudifasciatus ), and from P. longirostris by body depth (BD 35.4-42.1% SL versus 31.1-35.3% in P. longirostris ), and by its deep caudal peduncle (length as % of depth 57.6-86.5% versus 88.5-105.6% in P. longirostris ).

Description. Measurements and meristic counts for holotype and 8 paratypes are given in Table 1.

A robust, deep-bodied species (BD 35.4-42.2% SL, 40.0-42.2% in specimens over 50 mm SL). The four largest specimens are males (91.2, 79.2, 53.7, 49.5 mm SL) with minimal development of the testes; the remainder are immatures of indeterminate sex. Currently we have limited information on sexual dichromatism in the species. First ray of pelvic fin is the longest in the fin and is produced in large males reaching to, or overlapping the anal fin spines. Caudal fin is rounded.

Osteology and dentition. Infraorbital series (Fig. 2a) first infraorbital (commonly termed the lachrymal) is plate-like and followed by four tubular elements. There is a small gap between the fourth and fifth infraorbitals. Infraorbital 1 has four openings of the laterosensory system. Twenty five vertebrae, of which 13 are precaudal and 12 caudal. Premaxilla and dentary with 1-3 rows of small, acutely pointed, unicuspid teeth. Outer row teeth are slightly larger than those of inner rows. Lower pharyngeal bone is 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 9-12 tuberculate gill rakers, 5-6 elongate gill rakers on the epibranchial. No microbranchiospines are present. A well-developed hanging pad is present on roof of the pharynx.

Squamation. Cycloid, 2-3 rows of scales on the cheek, 3-4 horizontal rows on the opercle. Naked dark spot on the outer edge of opercle. Chest scales are smaller than scales on flanks.

Upper lateral line separated from dorsal-fin base at its highest point (8th pored scale) by 2 scales, at last pored scale by ½-1 scales. No overlap between the end of upper lateral line and lower lateral line. Caudal fin scaled basally for about one third of its length; other fins are unscaled.

Coloration. Living specimens: Base body coloration is pale bronze brown with a dark spot on outer edge of opercle, no other body markings are evident. Dorsal, anal and caudal fin membranes with numerous rows of dark maculae (MLJS, pers. field obs.).

Preserved specimens (Fig. 1): Coloration of the head and body is pale to dark brown and darker dorsally than ventrally. A midlateral stripe is variously developed, passing from the eye through the opercular spot onto the anterior third of the body. The midlateral stripe is interrupted from mid-body to the caudal peduncle, and does not extend over the caudal fin. Four-5 vertical bars are variously developed from the dorsum to somewhat below the midlateral stripe. The unpaired fins are dusky grey to brownish. The soft-dorsal, soft-anal and caudal fin membranes have numerous rows of dark maculae.

Breeding behaviour. No information available.

Distribution (Fig. 3). Currently known only from the Ivindo River system in the regions of Makokou and Belinga, Central Gabon.

Etymology. Named for Herbert Axelrod in recognition of his generous support of ichthyological research and exploration.

Remarks. Despite considerable collecting efforts in the Ivindo River ( Géry, 1965; pers. obs.), particularly in the region of Makokou, very few specimens of P. axelrodi have so far been collected, and the species is currently known only from the nine specimens of the type series. These have all been collected in small forest creeks and streams (marigots), but not in the main channel of the Ivindo River.