Odaxothrissa ansorgii Boulenger, 1910
Ansorge's fangtooth pellonuline
Odaxothrissa ansorgii
photo by FAO

Family:  Clupeidae (Herrings, shads, sardines, menhadens), subfamily: Dorosomatinae
Max. size:  13 cm SL (male/unsexed)
Environment:  pelagic; freshwater; brackish,
Distribution:  Africa: Western Africa, from Senegal to Angola (Ref. 188, 3509); including lower Senegal River and lagoons in Côte d'Ivoire (Ref. 54749, 81269), Niger Delta (Ref. 81269), Ogowe River (Ref. 81631), and rivers between Kouilou River in Congo Republic (Ref. 81631) and Cuanza River in Angola (Ref. 28136, 54749, 120641).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 14-18; Anal spines: 0-0; Anal soft rays: 17-21; Vertebrae: 44-46. Diagnosis: Body moderate, often deep, its depth 25% of standard length or more; 13-17 pre-pelvic and 8-11 post-pelvic scutes, 1-2 scutes before pectoral fin origin, first pre-pectoral scute longer and more developed than following scutes without ascending arms; lower jaw strongly projecting, with strong canine teeth at symphysis; pre-maxilla with 2-4 strong backward-pointing canine teeth on each side behind outer row of pre-maxillary teeth; lower gillrakers 22-33, shorter than corresponding gill filaments; anal fin with 17-21 rays; silver stripe along flank (Ref. 188, 54749, 81269, 81631). It resembles Odaxothrissa mento, which has fewer gillrakers, 16-19 vs. 22-33; and Pellonula vorax, which lacks canine teeth in the upper jaw and has longer gillrakers, equal in length to gill filaments vs. shorter (Ref. 188, 54749). Description: Body moderate, often deep; depth 25% of standard length or more (Ref. 188). Caudal peduncle as long as deep (Ref. 1869). Snout as long as eye, which is about 33% of head length, and exceeds the interorbital width (Ref. 1869). Lower jaw strongly projecting; pre-maxilla with 2-4 strong canine teeth on each side; maxillary extending to below centre of eye (Ref. 1869, 54749, 93833). First gill arch with 32-49 gillrakers; 22-33 gillrakers on the lower limb and 10-17 on the upper limb (Ref. 2849, 54749, 81269, 81631). Dorsal fin with 14-18 rays, first ray of dorsal fin placed slightly in front of or above the pelvic insertion; anal fin with 17-21 rays; pectoral fin with 13-16 rays; pelvic fin with 8 rays; caudal fin deeply forked, with pointed lobes (Ref. 188, 1869, 54749, 81269, 81631). Cycloid scales; 40-45 scales in longitudinal series, 16-17 scales in transverse series (Ref. 1869, 54749). With 13-17 pre-pelvic and 8-11 post-pelvic scutes; pre-pectoral scutes present, 1-2 scutes in front of pectoral fin origin, first pre-pectoral scute longer and more developed than following scutes without ascending arms (Ref. 188, 54749, 81269, 81631). Number of vertebrae 44-46; with 23-25 abdominal vertebrae and 18-21 caudal vertebrae (Ref. 2849, 54749, 81269, 81631). Colouration: Alcohol-preserved specimens are generally a light yellowish-grey, or yellowish-brown; gill cover, longitudinal stripe and ventral region much lighter (Ref. 2849, 54749, 81269, 81631). In life, upper half, with dorsal fin and base of caudal fin pale olive-green; lower half and other fins white; a broad silvery band along each side (Ref. 1869).
Biology:  Found in rivers and streams (Ref. 188), also in lagoons (Ref. 2849, 81269).
IUCN Red List Status: Least Concern (LC); Date assessed: 19 October 2019 Ref. (124695)
Threat to humans:  harmless
Country info:  Known from Niger Delta (Ref. 81269).


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