Pelvicachromis taeniatus (Boulenger, 1901)

Lamboj, Anton, Bartel, Daniela & Dell’Ampio, Emiliano, 2014, Revision of the Pelvicachromis taeniatus-group (Perciformes), with revalidation of the taxon Pelvicachromis kribensis (Boulenger, 1911) and description of a new species, Cybium 38 (3), pp. 205-222 : 216

Pelvicachromis taeniatus (Boulenger, 1901)

(Fig. 7)

Holotype. – BMNH 1901.1 .28.21, male, 60.3 mm SL, Nigeria, mouth of Ethiop River, Niger Delta ( Sapele Station ), W.J. Ansorge coll.

Additional specimens. – AMNH 97565 , 1 male , 2 females, 36.3-58.3 mm SL, Nigeria, Niger River system.

Diagnosis

A moderately gracile species, with rounded head and well-developed sexual dimorphism and dichromatism. Differs from all congeners by a coloration in male caudal fin with a white to yellow upper half of this fin, having a number of black dots in the dorsal half, without any margin, and a black margin with a white to pale bluish submargin in the lower half of this fin (vs no margin/submargin in lower half of this fin in all congeners with exception of P. drachenfelsi sp. nov. and a white margin and black submargin in upper half of caudal fin in P. drachenfelsi sp. nov.). Females differ from females of P. drachenfelsi sp. nov. and P. kribensis in having two or three horizontal dark bars in the caudal fin (vs none in P. drachenfelsi sp. nov. and one in some populations of P. kribensis ). Differs from P. drachenfelsi sp. now. in a caudal peduncle shorter then deep (vs usually longer then deep). Differs from P. humilis , P. rubrolabiatus and P. signatus in absence of seven-eight dark, vertical bars on body and in three tubular infraorbital bones vs two. Differs from P. silviae in lesser body depth (29.9-36.4% SL vs 37.4-43.0%, mean 34.6 vs 39.2%), shorter pre-anal distance (62.8-66.7% SL vs 66.2-69.8%, mean 65.6 vs 68.3%), shorter prepelvic distance (36.0-37.5% SL vs 37.9-44.3%, mean 36.9 vs 39.8%), and more spines in dorsal fin (17-18 vs 14-16). Differs from P. subocellatus in lesser body depth in males in lappet-like elongation of some rays of caudal fin (vs no such elongation). Differs from P. roloffi ( Thys van den Audenaerde, 1968) in greater caudal peduncle length (12.4-14.1% SL vs 9.4-12.2, mean 13.2 vs 10.7%) and more pored scales of lateral-line (26-28 vs 24-26). Differs from P. sacrimontis Paulo, 1977 in shorter interorbital distance (21.4-26.8% HL vs 29.4-45.3%, mean 23.7 vs 36.0%). Differs from P. pulcher (Boulenger, 1901) in shorter preorbital distance (18.6-21.2% HL vs 21.0-33.8%, mean 20.2 vs 24.9%), and in rows of dots in the central field and lower part of the male caudal fin (vs absence).

Description

Measurements and meristic counts for holotype and 3 additional specimens are presented in table III. Small cichlid species with body moderately gracile, dorsal head profile rounded and short snout. Ventral body wall gently rounded toward caudal peduncle, more rounded in ripe and gravid females. Caudal fin rounded. Caudal peduncle shorter than deep. Sexual dimorphism well developed, with males usually 10-15% larger in SL than females and with soft dorsal, anal and pelvic fins more elongated. First ray of pelvic fin always longest in males, in females second ray of this fin always longest. In males, tip of pelvic fin can reach or overlap origin of anal fin.

Osteology and dentition. – Infraorbital bone series with lachrymal and three additional tubular bones and a gap between 2 nd and 3 rd tubular infraorbital; lachrymal with four openings of laterosensory system.

Premaxilla with 1 or more often 2 rows, dentary with 2 rows of regularly set unicuspid teeth. Anteriorly in the lower jaw a few teeth orientated posteriorly, not buccally. Lower pharyngeal bone triangular, with unicuspid to weakly bicuspid teeth on lateral parts of this bone, and asymmetric bicuspid teeth in the central field.

Gill rakers on first gill arch. Nine to 10 tuberculate gill rakers on ceratobranchials, 5 or 6 pointed gill rakers on epibranchials. Well-developed hanging pad on roof of pharynx.

Scales. – Cycloid, 2 or 3 rows of scales on cheek; 4 horizontal rows on opercle. Dark spot on outer edge of opercle unscaled. Chest-scales smaller than body scales, 3 or 4 scales between pectoral and pelvic fins. Upper lateral-line separated from dorsal-fin base anteriorly by two and a half to three and a half scales, at the 8 th pored scale by one or one and a half scales, and at last pored scale by a half or one scale. End of upper lateral-line never overlapping lower lateral-line, usually separated from beginning of lower lateral-line by no to two rows of scales. About 1/5 to 1⁄4 of caudal fin covered with scales, all other fins unscaled.