Polydactylus quadrifilis (Cuvier, 1829)
Giant African threadfin
Polydactylus quadrifilis
photo by Klimpel, S.

Family:  Polynemidae (Threadfins)
Max. size:  200 cm TL (male/unsexed); max.weight: 75 kg
Environment:  demersal; freshwater; brackish; marine; depth range 15 - 55 m
Distribution:  Eastern Atlantic: Senegal to Angola (Ref. 57402). Also reported from Mauritania (Ref. 55783).
Diagnosis:  Dorsal spines (total): 9-9; Dorsal soft rays (total): 12-13; Anal spines: 3-3; Anal soft rays: 11-12. Diagnosis: pectoral fin with 4 threadlike filaments (Ref. 57402, 81658). Pectoral fin inserted very low on body, generally somewhat longer than upper part of fin (Ref. 57402). Description: Body moderately compressed (Ref. 57402) and elongate, its depth 4-4.5 times in SL (Ref. 57402, 81658). Detached pectoral filaments short, only slightly longer than upper pectoral fin; base of anal fin as long as base of 2nd dorsal fin; snout very short, blunt and prominent; mouth inferior; maxillary bone distinctly widened at its end, reaching largely past eye (Ref. 57402). 2 widely separated dorsal fins, 1st with 8 flexible spines (Ref. 57402), 2nd with one flexible spine and 12-13 soft rays (Ref. 57402, 81658). 2nd dorsal fin and anal fin bases nearly equal; scales ctenoid; head scaly (Ref. 57402). Coloration: body uniformly (pale) silvery, greyish-brown to black on back, shading to whitish ventrally; dark, blackish blotch often present on gill cover (Ref. 57402, 81658). Both dorsal fins generally greyish and blackish anteriorly; 1st dorsal fin with a black tip; pectoral fins greyish to black or yellowish; pectoral filaments white; pelvic fins white; anal fin variably white or greyish to black; caudal fin greyish and bordered with black (Ref. 81658).
Biology:  Occurs in shallow coastal waters, over sandy and muddy bottoms, sometimes in brackish habitats (Ref. 57343, 81658). Enters estuaries (Ref. 57402), occasionally caught in fresh water (Ref. 57402, 81658). Very large specimens are only found in marine waters (Ref. 81658). Feeds on crustaceans and fishes (Ref. 10799, 81658). Flesh fairly tasteful (Ref. 57402).
IUCN Red List Status: Least Concern (LC); Date assessed: 15 July 2014 Ref. (130435)
Threat to humans:  harmless


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