Grasseichthys gabonensis Géry, 1964
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Family:  Kneriidae (Shellears), subfamily: Kneriinae
Max. size:  2.06 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater,
Distribution:  Africa: scattered localities in the Ivindo and the larger Ogowe basin of Gabon; reports from the central Congo basin refer to another species (Ref. 81636).
Diagnosis:  Dorsal spines (total): -0; Dorsal soft rays (total): 7-8; Anal spines: -0; Anal soft rays: 9-10; Vertebrae: 35-36. Diagnosis: very small and larval in appearance; body elongate, laterally compressed, shallow (body depth 17.9-20.0% SL in females and 15.2-17.9% SL in males); scaleless; head small (head length 18.0-22.7% SL), with small, terminal mouth and large eyes; teeth absent; interorbital distance narrow (11.9-12.9% HL); gill opening short and located above pectoral fin; pectoral fins positioned ventrally and often splayed out from the body in preserved specimens; caudal peduncle long, with keels of transparent tissue, apparently anterior extensions of caudal fin membrane, reaching forward on both dorsal and ventral edge (ventral extension is more developed); caudal fin forked, with 16 rays, including an unbranched ray on dorsal and ventral edge; fin spines lacking; 2 branchiostegal rays; body semi-translucent, with myomeres clearly visible; lateral line absent; epibranchial organ reduced or absent (Ref. 81636). Description: dorsal fin slightly in front of anal fin (Ref. 91379). Ref. 89095 reports only 6 dorsal and anal soft rays, 4-5 pectoral fin rays and 6 pelvic fin rays (Ref. 89095). Details on osteology of skull and anterior vertebrae with associated structures in Ref. 89095 and 91379; details on hypural complex in Ref. 91379. Coloration: base body colouration of preserved specimens yellowish; skin transparent, with scattered melanophores on body, especially along dorsal and ventral surfaces; melanophores slightly clustered into an indistinct line running along the middle of the abdomen; a distinct, dark mid-lateral line of melanophores runs the full length of the flank, bisecting the angles formed by the myomeres; melanophores also occur along the rays of all fins and in a large, dark, diamond-shaped spot at the base of the caudal fin (Ref. 81636).
Biology:  Open water species, not burrying in sand; forms schools; spawns during the raining season, during which it may be very abundant, forming aggregations in open water areas in the swamps; females of 20-24mm carry about 40 round, ripe eggs of about 0.4mm diameter; males mature at a size of about 18mm total length (Ref. 91379).
IUCN Red List Status: Vulnerable (VU); Date assessed: 16 February 2009 (B1ab(iii)+2ab(iii)) Ref. (124695)
Threat to humans:  harmless
Country info:   

Entered by: Sa-a, Pascualita - 18.06.94
Modified by: Musschoot, Tobias - 05.09.12

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