Simpsonichthys boitonei

Wilson J. E. M. Costa, 2007, Taxonomic revision of the seasonal South American killifish genus Simpsonichthys (Teleostei: Cyprinodontiformes: Aplocheiloidei: Rivulidae)., Zootaxa 1669, pp. 1-134 : 36-38

Simpsonichthys boitonei Carvalho, 1959

(Figs. 21-22)

Simpsonichthys boitonei Carvalho, 1959: 5 ( type locality: temporary pool, area of the future Zoological Garden, Brasilia , Goiás [now Distrito Federal], Brazil [approximately 15°45’S 48°00’W]; holotype: MNRJ 9012 ).

Material examined

Brazil: Distrito Federal: rio São Bartolomeu drainage, rio Paraná basin: MNRJ 9012 , holotype, male, 19.0 mm SL; MNRJ 9013/17 , 5 paratypes; temporary pool, Zoological Garden, riacho Fundo drainage, Brasilia ; J. Boitone, Apr. 1959. MNRJ 11376 , 3; same locality as holotype ; unknown collector, Feb. 1976. MZUSP 38418 , 1 (c&s); Reserva do IBGE ; M. Ribeiro, May 1986. UFRJ 4071 , 2; UFRJ 4988 , 1 (c&s); corrego Roncador, Reserva Ecologica IBGE (Instituto Brasileiro de Geografia Estatistica ) ; A. Sarraf, M. Ribeiro & E. C. Lopes, 3 Mar. 1997. UFRJ 6348 , 4; UFRJ 6349 , 7; UFRJ 6350 , 4 (c&s); upper riacho Fundo drainage, Brasilia ; G. C. Brasil, 3 Jun. 2005.

Diagnosis

Similar to S. parallelus and S. cholopteryx , and distinguished from all other cynolebiatins by the absence of pelvic fins and pelvic girdle. Differs from S. parallelus and S. cholopteryx in having the dorsal-fin origin anterior to anal-fin origin (vs. posterior), more dorsal-fin rays in males (19-22, vs. 17-18), fewer anal-fin rays in males (17-19, vs. 20-23), iridescent dots on unpaired fins in males (vs. iridescent dots absent), and pectoral fins red, with metallic blue spots in males (vs. hyaline).

Description

Morphometric data appear in Table 2. Largest specimen examined 36.3 mm SL. Dorsal profile convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile convex from lower jaw to end of anal-fin base, nearly straight on caudal peduncle. Body moderately deep, compressed, greatest body depth on vertical just anterior to dorsal-fin origin. Eye positioned on dorsal portion of head side. Snout blunt. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of both dorsal and anal fins pointed in males, rounded in females. Tip of dorsal and anal fins with short filamentous rays in males, tip of filaments reaching vertical through caudal-fin base. Dorsal-fin rays unbranched. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of each pectoral fin reaching vertical between base of 4th and 6th anal-fin rays in males, on vertical through anus in females. Pelvic fins and pelvic girdle absent. Dorsal-fin origin anterior to anal-fin origin, anal-fin origin on vertical between base of 3rd and 5th dorsal-fin rays in males, between base of 1st and 2nd dorsal-fin rays in females. Dorsal-fin origin between neural spines of vertebrae 7 and 8 in males, between neural spines of vertebrae 10 and 11 in females. Anal-fin origin between pleural ribs of vertebrae 8 and 10 in males, between pleural ribs of vertebrae 9 and 11 in females. Dorsal-fin rays 19-22 in males, 14-16 in females; anal-fin rays 17-19 in males, 16-18 in females; caudal-fin rays 25-28; pectoral-fin rays 13-14.

Frontal squamation E-patterned; E-scales overlapping medially; no scale anterior to G-scale; two small supraorbital scales. Longitudinal series of scales 25-26; transverse series of scales 10-11; scale rows around caudal peduncle 12-14. Papillate contact organ on each scale of flank below lateral line. Small papillate contact organs on upper surface of three dorsalmost rays of pectoral-fin in males.

Cephalic neuromasts: supraorbital 14-17, parietal 2-3, anterior rostral 1, posterior rostral 1, infraorbital 1-2 + 22-23, preorbital 4-5, otic 2, post-otic 2-3, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 16-17, mandibular 11-12, lateral mandibular 6-7, paramandibular 1. One neuromast on center of each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 50% of length; basihyal cartilage about 25% of total length of basihyal. Six branchiostegal rays. One second pharyngobranchial teeth. Gill-rakers on first branchial arch 3 + 10. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal short. Total vertebrae 26-28.

Coloration

Males. Sides of body crimson red, with 12-15 vertical rows of bright blue dots, dots of anterior rows coalesced forming bars. Dorsum reddish brown. Venter pink. Sides of head crimson red, with five greenish blue bars between area adjacent to anterior margin of orbit and posterior portion of opercle. Iris yellow, with dark brownish red bar through center of eye. Dorsal and anal fins orangish red to dark grayish red on distal third of fins, with small light greenish blue spots on basal region, row of slightly larger blue spots on subdistal region sometimes coalesced to form stripe, and narrow light blue distal margin. Caudal fin orangish red, with light blue dots and traces parallel to fin rays, and light blue marginal line along margin, often wider on dorsal and ventral margins. Pectorals reddish hyaline, with blue spots on basal portion of fin.

Females. Sides of body pale brown, with 11-14 dark brownish gray bars, alternating with golden to light blue narrow bars on anterior portion of flank; one to three vertically elongated black blotches on anterocentral part of flanks. Dorsal light brown. Venter light yellowish white. Sides of head pale brown, with four dark brownish gray bars alternating with five light golden bars. Iris yellow, with brown bar through center of eye. Fins hyaline, sometimes with faint gray spots on basal portion of dorsal and anal fins.

Distribution

Upper rio São Bartolomeu drainage, itself part of rio Corumbá drainage, upper rio Paraná basin, central Brazil (Fig. 1).

Habitat

Temporary pools in Campo Úmido and Mata de Galeria, in the Cerrado.