Simpsonichthys Simpsonichthys boitonei Taxonomic revision of the seasonal South American killifish genus Simpsonichthys (Teleostei: Cyprinodontiformes: Aplocheiloidei: Rivulidae). Wilson J. E. M. Costa Zootaxa 2007 1669 1 134 urn:lsid:zoobank.org:act:BD08FA7B-788B-4285-9548-0F120F97465D Rivulidae Simpsonichthys CoL Animalia Simpsonichthys Carvalho 1959:2 Cyprinodontiformes 25 Chordata subGenus Simpsonichthys urn:lsid:zoobank.org:act:BAEE987F-0345-41BB-9ECD-59D4F5DB9501 Rivulidae Simpsonichthys CoL Animalia Simpsonichthys cholopteryx Costa, Moreira & Lima 2003:140 Cyprinodontiformes 25 Chordata species cholopteryx   SimpsonichthysCarvalho, 1959: 2 (type species: Simpsonichthys boitoneiCarvalho; type by original designation).  Diagnosis Distinguished from all other cynolebiatines by having pelvic fin and pelvic-fin girdle vestigial or absent and dark red bars on opercle in males.  Distribution Headwaters of rio Parana, rio SaoFrancisco, and rio Araguaia basins, central Brazil (Figs. 1 and 4).  Key to species of the subgenus Simpsonichthys 1a. Dwarf species, reaching about 25 mm SL; caudal fin with dark gray margin and subdistal blue line in males; dark gray distal stripe on dorsal and anal fins in males; pectoral fins hyaline in males ......................... 2 1b. Median sized species, reaching about 40 mm SL; caudal fin without dark margin and subdistal blue line in males; red distal stripe on dorsal and anal fins in males; pectoral fins red in males ................................ 4 2a(1a). 17-20 anal-fin rays in females; dorsal and anal fins orange in males; no dark bars on unpaired fins in males ........................................................ 3 2b(1a). 20-22 anal-fin rays in females; dorsal and anal fins light blue anteriorly, yellow posteriorly in males; dark red bars on unpaired fins in males ....................................... S. cholopteryx 3a(2a). No black spots on posterobasal portion of dorsal fin in males; no yellow dots on caudal fin in males; body depth in males 28.8-32.5 % SL ......................... S. parallelus 3b(2a). Two to four black spots on posterobasal portion of dorsal fin in males; yellow dots on caudal fin in males; body depth in males 33.5-36.0 % SL ............................................................ S. nigromaculatus 4a(1b). No longitudinal rows of light blue dots on flank in males; short filamentous ray on tip of dorsal fin in males, reaching basal portion of caudal fin ..................................................................................... 5 4b(1b). Longitudinal rows of light blue dots on flank in males; long filamentous ray on tip of dorsal fin in males, reaching the distal portion of caudal fin .............................................................. S. punctulatus 5a(4b). Pelvic fins vestigial; 20-23 anal-fin rays in males; black spots on dorsal-fin base in males.. .......... 6 5b(1b). Pelvic fins absent; 17-19 anal-fin rays in males; no black spot on dorsal-fin base in males.. ............. ....................................... S. boitonei 6a(5a). Dorsal-fin rays 19-21 in males, 14-17 in females; dorsal-fin origin anterior to anal-fin origin in males ..................................... S. santanae 6b(5a). Dorsal-fin rays 15-17 in males, 12-13 in females; dorsal-fin origin posterior to anal-fin origin in males ...................................................... S. zonatus