Potamothrissa acutirostris (Boulenger, 1899)
Sharpnosed sawtooth pellonuline
photo by FAO

Family:  Clupeidae (Herrings, shads, sardines, menhadens), subfamily: Dorosomatinae
Max. size:  7 cm SL (male/unsexed)
Environment:  pelagic; freshwater,
Distribution:  Africa: widespread in Congo River basin (Ref. 188, 28136) in the Democratic Republic of the Congo (Ref. 93833, 122734) and Central African Republic (Ref. 45441), also Lake Mweru in Zambia (Ref. 52959).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 13-14; Anal spines: 0-0; Anal soft rays: 16-20. Diagnosis: Body slender, its depth 19-27% of standard length; pre-pelvic scutes fairly strongly keeled, beginning under or just before pectoral fin base, 11-13 pre-pelvic and 10-12 post-pelvic scutes; snout pointed; lower jaw not projecting, included in upper when mouth closed, deepest at mid-point of jaw, with small saw-like teeth on either side; pre-maxillae with rather peg-like teeth, those near mid-line pointing forward; maxilla very slender, its blade over 3 times as long as deep, upper edge ridged, lower edge without denticulations; posterior supra-maxilla very small, spatulate, its shaft about as long as its blade; lower gillrakers 16-18 (Ref. 188). It differs from Potamothrissa obtusirostris and P. whiteheadi in its pointed snout, more gillrakers, 16-18 vs. 14-16 and 14-17 respectively, and first pre-pelvic scute beginning under or just before pectoral fin base (Ref. 188, 28136). Other pellonulines lack saw-like teeth at the sides of the lower jaw (Ref. 188). Description: Body slender, its depth 19-27% of standard length (Ref. 188). Caudal peduncle a little longer than deep (Ref. 1877, 1878, 93833). The upper profile of the head is a little less oblique than the lower profile; snout, acutely pointed and and projecting slightly beyond lower jaw, is as long as eye diameter, which is one third of head length and slightly exceeds interorbital width; maxillary extending a little beyond anterior border of eye; a well-developed adipose eye lid; teeth unequal in size, none very strongly enlarged (Ref. 1877, 1878). Gill-rakers slender, much shorter than branchial filaments, about 16-18 on lower part of anterior arch (Ref. 188, 1878, 93833). Dorsal fin with 13-14 rays, its origin above first ray of pelvic fin, much nearer end of snout than base of caudal fin; anal fin with 16-20 rays, its origin well behind last rays of dorsal fin, nearly twice as distant from base of pelvic fin as from caudal fin; pectoral fin not reaching pelvic fin; caudal fin forked, with pointed lobes (Ref. 1877, 1878, 93833). Scales: 36-42 scales in longitudinal series; 10 transversal scales (Ref. 1877, 1878, 93833). With 11-13 keeled pre-pelvic scutes and 10-12 post-pelvic scutes; pre-pelvic scutes fairly strongly keeled, beginning under or just before pectoral fin base (Ref. 188, 1877, 1878, 28136). Colouration: Olive coloured dorsally, whitish ventrally, with a silvery lateral band; sometimes a large dark spot on gill-cover and scapular region, and another at base of caudal fin; iris silvery, with a yellow circle around the pupil, which is elongated vertically (Ref. 1877, 1878).
Biology:  Found in rivers and lakes, apparently in both running and still water (Ref. 188), but not swimming upriver in the smaller streams (Ref. 4910). The distribution of this species suggests that it tolerates a wide variety of water conditions (Ref. 188).
IUCN Red List Status: Least Concern (LC); Date assessed: 16 February 2009 Ref. (124695)
Threat to humans:  harmless
Country info:   
 

Entered by: Binohlan, Crispina B. - 17.10.90
Modified by: Boden, Gert - 02.10.19
Checked by: Binohlan, Crispina B. - 23.07.94

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