Labeo fulakariensis, Sinaseli M. Tshibwabwa, Melanie L. J. Stiassny & Robert C. Schelly, 2006

Sinaseli M. Tshibwabwa, Melanie L. J. Stiassny & Robert C. Schelly, 2006, Description of a new species of Labeo (Teleostei: Cyprinidae) from the lower Congo River., Zootaxa 1224, pp. 33-44 : 38-40

Labeo fulakariensis , new species.

(Figures 3-5; Table 3)

Holotype: AMNH 236426: Channel in rocks, 1 km upstream of Foulakari, Congo main channel, Lower Congo River, Rotenone. Republic of Congo (4º34.71 S - 14º59.74 E). 07.VIII.2004; SL: 111.6 mm.

Paratypes: AMNH 236427: Channel in rocks, 1 km upstream of Foulakari, Congo main channel, Lower Congo River, Rotenone. Republic of Congo (4º34.71 S - 14º59.74 E). 07.VIII.2004; SL: 86.1 mm. AMNH 236428: Mbouono, rotenone applied to partially isolated pool of Congo main channel, downstream of Brazzaville, Lower Congo River. Republic of Congo (4º20.19 S - 15º11.02 E). 20.VIII.2004; SL: 130.3 mm. ZSM 34488: Rapids near Yelala. Rotenone applied to high gradient riffle with aquatic macrophytes, flowed through holes and under cracks into several pools, fish collected at downstream constriction; Lower Congo River. Democratic Republic of Congo (5º43.51 S - 13º32.50 E). 12.VII.2005; SL: 124.2 mm.

Differential diagnosis

Labeo fulakariensis is distinguished from all Congolese Labeo except L. greenii and L. reidi by the combination of plicate lips, characteristic striping of the flanks, and a dark spot restricted to the midbase of the caudal peduncle. Labeo fulakariensis is distinguished from L. greenii in the possession of a concave dorsal fin (vs. falciform in greenii), a flat dorsal profile between the eyes (vs. rounded in greenii), and a snout without a deep transverse furrow or upwardly directed fleshy anterior appendage (vs. snout with deep transverse furrow and upwardly directed fleshy appendage in greenii). L. fulakariensis is distinguished from L. reidi (a species known only from the Middle Congo) by the position of eye which is supero-lateral (vs lateral in L. reidi ), 16 circumpeduncular scales (vs. 17 to 20 in L. reidi ), and the maxillary barbels which are well-developed but smaller than in L. reidi and never visible externally (in L. reidi , maxillary barbels are well-developed, larger and always visible externally).

Description

Based on the holotype and three paratypes. Maximum size 179.7 mm SL. Counts and proportional measurements are presented in Table 3. Body robust, more-or-less laterally compressed, flanks with longitudinal striping, and a large black spot situated at the base of the caudal peduncle. Genital opening situated near the anal fin origin. Mouth large, rostral lobe denticulate; lips with transverse plicae on the inner surface. Maxillary barbels welldeveloped, hidden at the corners of the mouth; rostral barbels small and hidden beneath rostral lobe. Interorbital profile flat, snout not prominent, with few tubercles, and without a deep transverse furrow or fleshy appendage at its anterior end. Eyes in supero-lateral position and not visible from the ventral face. Dorsal fin concave with 4 unbranched and 10 branched rays. Pectoral fins in latero-ventral position, distant from pelvic fins, their tips extending just beyond the origin of the dorsal fin; pelvic fins short, not reaching the genital opening. Anal fin not reaching the extremity of the scaly caudal fin. Caudal fin deeply notched, with pointed lobes; the upper lobe slightly more developed than the lower. Thirty-one to 32 vertebrae. Thirty-eight to 39 pored scales in lateral line, 61/2 scale rows between dorsal fin origin and lateral line, 4-5 scales rows between lateral line and pelvic fin insertion, and 16 circumpeduncular scales.

Coloration

Alcohol preserved specimens are dark brown dorsally and beige-yellow ventrally; lighter from the genital opening to the inferior part of the scaly caudal fin. The scales of each longitudinal flank row bear a more-or-less well marked black spot in the midfield. The resulting patterning on the flanks resembles a series of longitudinal stripes although each “stripe” is composed of a series of unconnected black scale spots. A large black spot is present on the caudal peduncle; the caudal spot is restricted to the caudal peduncle and does not extend onto the scaly caudal fin base. A well-developed and strongly marked post opercular spot is present just above the pectoral fin. All fins are whitish with a smoky grey overlay.

Reproduction Unknown.

Distribution and habitat

Collected from the main channel of the Congo River in the lower rapids, from near Brazzaville to Yelala (See Fig. 5). Pending the results of ongoing biodiversity studies in this area, current distributional data suggest that Labeo fulakariensis is restricted to the Lower Congo River a region already characterized by another endemic Labeo , L. rectipinnis (Tshibwabwa, 1997) and numerous other endemic fish species (Thieme et al., 2005).

Specimens were captured either in protected backwaters influenced by periodic surges, or in flowing water comprised of alternating riffles and pools in rock fissures along the bank of the Congo. Smooth rock faces in these habitats bore visible tracks with the characteristic lip imprints of grazing Labeo .

Etymology

Named in reference to the Foulakari River, Republic of Congo, in the vicinity of which most of the type series was collected.