Chromidotilapia melaniae, Anton Lamboj, 2003

Anton Lamboj, 2003, Chromidotilapia melaniae and C. nana, two new cichlid species (Perciformes, Cichlidae) from Gabon, Central Africa., Zootaxa 143, pp. 1-15 : 2-7

Chromidotilapia melaniae , new species

(Figs. 1-4)

Holotype. AMNH 232533, female, 53.0 mm SL; Gabon: Small creek on route Tchibanga-Mayumbe east of the village Malounga, Yola system; A. Lamboj, D. Altmann, M. Hasselmann, F. Panholzer, July 2000.

Paratypes. All from Gabon. AMNH 232534, 2 females, 52.7 + 60.1 mm SL; same data as holotype. - AMNH 232535, 1 male, 1 undet., 43.0 + 62.8 mm SL; Riv. Biwegeni, 30 km south of Lambarene on route to village Tchad, Ogooue system; A. Lamboj, D. Altmann, M. Hasselmann & F. Panholzer, Aug 2000. - CU 79914, 7 males, 6 females, 5 undet., 34.4-79.5 mm SL; Nyanaga River at Nyanga Bridge, Tchibanga, 2° 55´S, 10° 59´E; J. P. Friel, Ange, July 1999. - MRAC-A2-011-P-7-9, 1 male, 2 females, 46.7-62.4 mm SL; same data as holotype. - NMW 94633, 1 male, 1 female, 1 undet, 41.4-54.8 mm SL; same data as holotype.

Additional material. Four pairs from the type locality and 6 pairs from the same locality as AMNH 232535. Behavioural observations were made on these specimens, but they were not included in the type series.

Diagnosis. A species of Chromidotilapia with the following combination of characters: Dentary pores 5; gill rakers on lower limb of first arch 8-10; lower jaw with 2-3 rows of unicuspid teeth; snout relatively acute; no iridescence on cheek, operculum and flanks; and stressed individuals with two rows of dark longitudinal stripes and small blotches.

Description. Measurements and meristic counts for holotype and 28 paratypes are given in Table 1.

Sexual dimorphism and dichromatism well developed. First ray of pelvic fin longest in both sexes, but always more produced in males than in females. Pelvic fin reaching or overlapping spinous anal fin in both sexes when adducted. Caudal fin rounded. Dorsal head profile straight to moderately curved; pointed snout.

Osteology and dentition. Infraorbital series complete, comprising lachrymal and four additional bones; lachrymal with five openings of laterosensory system. Neurocranial apophysis of Tilapia type. Vertebral count 25-27, 13-14 abdominal and 12-13 caudal.

Premaxilla with 1-3, dentary with 2-3 rows of unicuspid teeth. Anteriorly in lower jaws some teeth orientated posteriorly, not buccally. Lower pharyngeal bone triangular, with shouldered unicuspid teeth in lateral fields and asymmetric bicuspid teeth in central field.

Gill rakers on first arch. Eight-10 tuberculate gill rakers on hypobranchial + ceratobranchial, 5-8 pointed gill rakers on epibranchial. Well developed visor-like hanging pad on roof of the pharynx.

Squamation. Cycloid, 3-4 rows on cheek, 3-4 horizontal rows on opercule. Naked dark spot on outer edge of opercule. Chest scales smaller than body scales.

Upper lateral line separated from dorsal-fin base on highest point (8th pored scale) by 2½-1½ scales, on last pored scale by 1½-½ scales. End of upper lateral line sometimes overlapping lower lateral line by one scale row, about ¼ - 1/3 of caudal fin basally covered with scales; other fins unscaled.

Coloration. Living specimens of both sexes (Figs.2-4): Head and body brown to dark brown. Dark scaleless spot on the outer edge of opercle. Upper lips brown, lower lips white to bluish-grey. Two rows of dark longitudinal stripes and small blotches sometimes visible on flanks (in stressed individuals), often combined with 5-7 dusky vertical bars (Fig.4). Upper longitudinal row begins more or less at highest point of upper lateral line and continues under dorsal fin base. Second row extends from outermost edge of opercle to caudal peduncle. Ventral parts of head, cheek and opercle light brown.

Male coloration (Fig.2): Dorsal fin hyaline to pale blue, with red margin and alternating white and red submargins, remainder of fin with patterns of red blotches (anterior parts) or short vertical stripes (posterior parts). Caudal fin pale violet, upper edge with red margin and white to light blue submargin, midregion with red and light maculae. Anal fin violet, with red and white to light maculae in distal field, dark margin on leading edge. Leading edge of pelvic fin dark violet to dark blue, other parts violet. Pectoral fin hyaline to slightly yellow. Body scales with dark margins.

Female coloration (Fig.3): Spinous dorsal and upper half of soft dorsal fin iridescent white or rosy, same along upper margin of caudal fin. Other parts of both fins violet to bluish, as in anal fin. Leading edge of anal fin with dark margin. Pelvic fins slightly bluish to yellow, with dark leading edge. Pectoral fins hyaline to slightly yellow. Belly of ripe and courting females pale rosy.

Preserved specimens (Fig. 1): Coloration of head and body brown, spots and blotches as in living specimens, but always a darker shade of brown.

Breeding behaviour. In aquaria a monogamous, pair bonding biparental ovophilic mouthbrooder. Eggs are deposited on a hard substrate (rocks, wood) or on leaves. After the entire clutch is deposited, eggs are normally incubated by the female for the first 2 or 3 days. After this a periodical change of incubation between female and male is possible - sometimes several times per day - but in most cases the female is more dominantly involved. In one pair, for one single brood, broodcare by only the male was observed.

Total incubation of eggs and larvae is for 12-14 days in the buccal cavity of the parents. When free swimming, juveniles are protected by both adults for a duration of about 4-6 weeks; during the first weeks - when disturbed or at night - fry are protected in the buccal cavity of both parents. Same is indicated in the wild, where one pair was observed taking care of a number juveniles.

Comparisons. Chromidotilapia melaniae differs from C. schoutedeni (Poll & Thys van den Audenaerde, 1967) in the number of pores on the lachrymal (4 in C. schoutedeni vs. 5 in C. melaniae ). It differs from C. guntheri (Sauvage, 1882) and C. regani (Pellegrin, 1906) in having fewer gill rakers on the lower limb of the first arch (8-10 vs. 11-16), and from C. nana in having 2-3 rows of unicuspid teeth in the lower jaw in adult specimens (vs. one row in C. nana ). It also has a distinctive colour pattern, differing from C. nana in having red spots and tips in the male dorsal, caudal and anal fins, from C. mrac Lamboj, 2002 and C. nana in having two rows of short longitudinal stripes and small blotches on the body when stressed (vs. two rows of large and small blotches), from C. cavalliensis (Thys van den Audenaerde & Loiselle, 1971) , C. guntheri and C. linkei Staeck, 1980 in possessing two rows of interrupted lines and spots vs. two uninterrupted lines, and from C. elongata Lamboj, 1998 in the absence of iridescence on the cheek, operculum and flanks. It differs from C. cavalliensis and C. guntheri in breeding behaviour (biparental in C. melaniae vs. male mouthbrooder in the others). It also differs from C. mrac and C. kingsleyae Boulenger, 1898 in breeding behaviour (female larvophilic mouthbrooder in C. mrac and polygamous ovophilic mouthbrooder in C. kingsleyae ). Finally it also differs from certain congeners in several morphometric details: the snout is more pointed, and head profile less rounded than in C. elongata , and it tends to have a more slender caudal peduncle (10.8-14.5% SL vs. 12.7-16.8% SL), a slightly smaller cheek depth (24.5-33.2% SL vs. 28.2-37.6% SL), and a more acute snout than C. mamonekenei Lamboj, 1998 .

Distribution. Gabon, coastal regions south of Ogooue River and central parts of country south of Lambarene in Ogooue and Nyanga river systems. In Ogooue system sympatric with C. kingsleyae and C. mrac , in western parts of Nyanga system sympatric with C. mamonekenei . Possibly not syntopic with both species.

Etymology. Dedicated to Melanie Stiassny, curator of fishes at the American Museum of Natural History (New York).

Remarks. For a number of years, C. melaniae has been referred to by aquarists as C. spec. “Shiloango” (e.g. Linke & Staeck, 2002), a denotation given to an undescribed species of the genus Chromidotilapia , deposited in the collections of MRAC by Thys van den Audenaerde (1968). These specimens have been examined, but it remains uncertain whether they are conspecific with C. melaniae (pers. obeservation). Therefore the denotation C. spec. “Shiloango” should be used only to refer to the Chromidotilapia specimens from Cabinda, deposited at MRAC, until living specimens from Cabinda are available for comparision of coloration and behaviour with C. melaniae .