Aphyosemion pusillum Chirio, Legros & Agnèse, 2018

Family:  Nothobranchiidae (African rivulines)
Max. size:  2.85 cm SL (male/unsexed)
Environment:  pelagic; freshwater
Distribution:  Africa: Okoyo and Pembé River basins in Gabon (Ref. 119374).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 9-12; Anal spines: 0-0; Anal soft rays: 11-14. Diagnosis: This species is distinguished from all other species in the Aphyosemion alpha group by two delimited orange zones on body: orange portion on opercle and orange portion above pelvic fins vs. no orange portion, with beige ventral portion vs. yellow-orange, white bluish or orange, anal fin orange, blue near basal portion and near submarginal red band, no punctuation vs. never a similar colour pattern (Ref. 119374). It is distinguished from all other species of the subgenus Chromaphyosemion by alpha-shaped mark on pre- and postopercular region, especially visible on preserved specimens, vs. no alpha-shaped mark, only some red macules (Ref. 119374). Description: Dorsal fin with 9-12 rays; anal fin with 11-14 rays (Ref. 119374). Lateral line with 24-27 scales; predorsal scales 13-15; transverse scales 7-8 (Ref. 119374). Colouration: Colouration of live males: flanks beige with two dark lateral stripes, two lines of small red dots from opercle to caudal peduncle; ventral region beige with some blue iridescent scales between end of anal fin and caudal peduncle, orange portion above pelvic fins; dorsal region light brown, two rows of paradorsal copper scales from operculum to caudal peduncle with two lines of red dots; head beige with premaxilla brown, mandible yellow orange with black lower lips, brown supraorbital region, beige infraorbital region with black macule, postorbital region beige with one black macule, beige preopercle with one black macule, opercle yellow orange in background with orange zone with four black macules; black macules on pre- and postopercular region reveal incomplete alpha-shaped mark; dorsal fin orange, yellowish on edge of fin, blue on posterobasal portion of fin, rows of carmine red dots between rays, red streaks on edge of fin, orange acumen on apex; anal fin orange, blue near basal portion of fin and near submarginal band, regular red submarginal band, yellow green marginal band, small orange acumen, no punctuation; caudal fin blue with beginning of upper and lower lobes light orange, red dots on upper part of fin, long red streaks on upper and median regions, red regular submarginal band, blue marginal band, orange acumens; pelvic fins orange without punctuation, blue near submarginal band, submarginal red band and yellow green marginal band; pectoral fins translucent (Ref. 119374). Colouration of live females unknown (Ref. 119374). Colouration of ethanol preserved males: flanks and venter grey with three incomplete lines of red dots, venter beige with orange portion, white lower part, two grey lateral stripes; two rows of paradorsal red scales in grey dorsal region from operculum to caudal peduncle; white mandible with black lower lips, white infraorbital region with black macule, white preopercular region, orange opercle; one dark macule in postopercular region; dorsal fin grey with rows of grey dots between rays; anal fin with grey area on basal portion; caudal fin grey with some red streaks on upper lobe, red dots in median portion (Ref. 119374).
Biology:  Found in the main course of small rivers, muddy streams less than 1 m wide, hidden among dead leaves and water plants, in quiet places (Ref. 119374).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless


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