Simpsonichthys nigromaculatus Costa, 2007

Family:  Rivulidae (Rivulines), subfamily: Cynolebiinae
Max. size:  2.56 cm SL (male/unsexed); 2.19 cm SL (female)
Environment:  benthopelagic; freshwater; pH range: 5.5; depth range - 0 m
Distribution:  South America: seasonal canals in the floodplains of rio da Prata, rio Aporé drainage, upper rio Paraná basin in Brazil.
Diagnosis:  Dorsal soft rays (total): 15-19; Anal soft rays: 17-22; Vertebrae: 24-25. Differs from all other species of the genus by possessing 2-4 black spots on posterobasal portion of dorsal fin in males. In addition, it can be separated from all congeners by the unique combination of the following characters: absence of pelvic fin and pelvic girdle; vertebrae 24-25; absence of second pharyngobranchial teeth; absence of ventral process of posttemporal; anal fin with 17-20 rays in females; body depth 33.5-36.0% SL in males; maximum adult size 25.6 mm SL; bright blue bars on flank in males much narrower than interspace; side of head in males with five alternating bright blue and pink to red bars; short postorbital pink strike connecting pink bars 2 and 3; anterior and posterior margins of iris bright blue; dark gray band bordered by a bright blue line on distal margin of dorsal and anal fins, and posterior margin of caudal fin in males; ground color of dorsal and anal fins orange in males; absence of bars on unpaired fins in males; and presence of yellow dots on the caudal fin in males (Ref. 75131). Description: longitudinal series of scales 24-26; transverse series of scales 9 (Ref. 75131).
Biology:  Inhabits temporary shallow canals (about 50 cm deep) in the floodplains, with light yellow water (Ref. 75131).
IUCN Red List Status: Vulnerable (VU); Date assessed: 07 November 2018 (D2) Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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