IUCN threat status:

Least Concern (LC)

Comprehensive Description

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General Description

Translation of original description by Poll (1945).

Body height included 2 5/6 and head 4 times in total length (minus caudal). Head 2 times as long as wide, slightly longer than deep, snout rounded & not prominent, 4 1/6 times HL. Mouth terminal, narrow, measuring the width of 1/6 of the length of the head. Teeth small, bicuspid, 5 in each jaw with a moderately protruding chin swelling; nares closer to each other than to tip of snout, on an oblique line a little nearer to the eye than the tip of the snout. Eye large, equal to the length of the snout, 4 1/6 times in HL, smaller than the interorbital width which is 3 1/6 times in HL. Dorsal 34, shorter than the distance which separates it from the head, length about 2 times the distance separating it from the tip of the nose; the longest anterior ray goes 2 1/5 times into HL. Anal 29, equidistant from the base of ventral and origin of the caudal fin, its origin below the 10th dorsal ray, its longest ray 1 5/6 times in the length of the head. Pectoral pointed, as long as the head, 2 times as long as the ventrals and extending rostrally to their terminus. Caudal lobes long and pointed. Caudal peduncle 3 times as long as high, measuring ¾ times in head. 138 scales in lateral line, about 14 / 12 about lateral line. On the body 10 / 9 between the origin of the dorsal and anal fins, 8 around the caudal peduncle. Scales along the lateral line very reduced, especially in front of the pelvic fins. Dorsal region dark brown, ventral regions largely free of scales, however finely pitted. Head brown with yellowish areas. The brown color is finely dotted with white [pores]. An oblique, indistinct blackish band between anterior rays of dorsal and anal fins. Dorsal, anal and ventrals somewhat darkened, especially at their base.

1 ex. type 132 mm TL., Busira River, Eala region, VI.l936, received from J. Ghesquière (Belgian Congo Museum, Tervuren).

Affinities: In the group of Gnathonemus in which the origin of the dorsal fin is in advance of the anal and in which the dorsal includes more than 30 rays, Gnathonemus ghesquierei is clearly distinguishable by its large scales and reduced scale counts: 38 lateral line scales and 8 scales around caudal peduncle. Body form, deepest near the origin of dorsal and a profile that descends in a smooth curve to the tip of the snout is reminiscent of some Marcusenius but we prefer to place this species in the genus Gnathonemus due to its terminal mouth and the presence of an chin swelling.

In any case, it is clear that the gap between these two genera is slight and that many species with terminal mouths could fall into either one of them. Compared to the genus Marcusenius, Gnathonemus ghesquierei differs profoundly from those species with dorsal fins in advance of the anal by its larger scales and reduced scale counts.

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© Poll, M.

Source: Africhthy

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