Potamothrissa obtusirostris (Boulenger, 1909)
Bluntnosed sawtooth pellonuline
photo by FAO

Family:  Clupeidae (Herrings, shads, sardines, menhadens), subfamily: Dorosomatinae
Max. size:  6 cm SL (male/unsexed)
Environment:  pelagic,
Distribution:  Africa: middle and upper Congo River basin (Ref. 3509, 28136, 93833), especially in northern and eastern tributaries (Ref. 188, 122734), and lower Congo River (Ref. 42510), in Central African Republic (Ref. 45441), Republic of Congo (Ref. 83895) and Democratic Republic of the Congo (Ref. 42480).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 13-15; Anal spines: 0-0; Anal soft rays: 16-20. Diagnosis: Body slender, its depth 18-27% of standard length; pre-pelvic scutes not strongly keeled, beginning under or behind base of last pectoral finray, 7-10 pre-pelvic and 9-12 post-pelvic scutes, belly rounded; snout bluntly rounded; lower jaw not projecting, exactly meeting tip of upper when mouth closed, deepest at mid-point of jaw, with small saw-like teeth on each side; pre-maxillae with small teeth pointing downward; 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 14-16; silver stripe on flank, narrower anteriorly (Ref. 188, 28136). It differs from Potamothrissa whiteheadi in having a distinct shaft to the posterior supra-maxilla and lacking dermal denticles on the snout, and from P. acutirostris in its blunt snout and fewer gillrakers, 14-16 vs. 16-18 (Ref. 188, 28136). Other pellonulines lack saw-like teeth at the sides of the lower jaw (Ref. 188). Description: Body slender, its depth 18-27% of standard length (Ref. 188). Caudal peduncle 1.2-1.5 times as long as deep (Ref. 1878, 93833). Snout obtusely pointed, projecting very slightly beyond lower jaw, not quite as long as eye, which is 3 times in head length and slightly exceeds interorbital width; adipose eyelid feebly developed; maxillary extending to below anterior third of eye; no strongly enlarged teeth (Ref. 1878, 41594). Gillrakers slender, shorter than branchial filaments, 14-16 on lower part of anterior arch (Ref. 188, 1878, 93833). Dorsal fin with 13-15 rays, originating slightly in advance of pelvic fins, much nearer end of snout than base of caudal fin; anal fin with 16-20 rays, twice as distant from base of pelvic fins as from caudal fin, and originating a long way behind vertical of dorsal; pectoral fin 60-66% of head length, not reaching pelvic fins; caudal forked, with pointed lobes (Ref. 1878, 41594, 93833). Scales: 39-45 scales in longitudinal series, 8-10 in transverse series (Ref. 1878, 41594, 93833). With 7-10 keeled pre-pelvic scutes and 9-12 post-pelvic scutes; pre-pelvic scutes not strongly keeled, beginning under or behind base of last pectoral finray (Ref. 188, 28136). Colouration: Body yellowish, head and a broad lateral band silvery (Ref. 1878). Silver stripe on flank, narrower anteriorly (Ref. 188).
Biology:  Found in rivers and streams (Ref. 41580), perhaps not in lakes (Ref. 188). It feeds on aquatic insects and also hydracarians (Ref. 188, 41580).
IUCN Red List Status: Least Concern (LC); Date assessed: 16 February 2009 Ref. (123251)
Threat to humans:  harmless
Country info:   

Entered by: Binohlan, Crispina B. - 17.10.90
Modified by: Boden, Gert - 08.10.19
Checked by: Binohlan, Crispina B. - 23.07.94

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