Simpsonichthys santanae

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 : 38-40

Simpsonichthys santanae (Shibata & Garavello, 1992)

(Figs. 23-24)

Cynolebias santanae Shibata & Garavello, 1992: 182 ( type locality: right bank of ribeirao Sant ’ana [Santana], Distrito Federal, 750 m from the boundary with Goias , Brazil, [16°2’31”S 47°45’38”W]; holotype: MZUSP 43777 ).

Material examined

Brazil: Distrito Federal, rio São Bartolomeu drainage, rio Paraná basin: MCP 15453 , 4 paratypes; temporary pool in the right bank of ribeirao Santana ; J. P. Viana, Jul. 1987. UFRJ 6389 , 16; UFRJ 6390 , 5 (c&s); same locality ; D. T. B. Nielsen & F. O. Pereira, 29 Apr. 2005.

Diagnosis

Distinguished from all other species of the subgenus Simpsonichthys , except S. zonatus , in having minute pelvic fins, with 5 rays (vs. long fins, with 6 rays in S. marginatus ; pelvic fins absent in S. boitonei , S. parallelus and S. cholopteryx ), and presence of vertically elongated, alternating, blue and black spots (vs. never a similar color pattern). Distinguished from S. zonatus in possessing more dorsal-fin rays (19-21 in males and 14-17 in females, vs. 15-17 in males and 12-13 in females), and dorsal-fin origin on vertical slightly anterior to anal-fin origin in males (vs. posterior to anal-fin origin).

Description

Morphometric data appear in Table 2. Largest specimen examined 32.0 mm SL. Dorsal profile convex from snout to end of dorsal-fin base, nearly straight on caudal peduncle. Ventral profile gently convex from lower jaw to end of anal-fin base, nearly straight on caudal peduncle. Body moderately deep, compressed, greatest body depth at level of pelvic-fin base. 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, the filaments reaching posteriorly to vertical through caudal-fin base. Dorsalfin rays unbranched. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of each pectoral fin reaching vertical between base of 4th and 7th anal-fins ray in males, on vertical through anus in females. Pelvic fins short, tips reaching base of 1st or 2nd anal-fin ray in males and between anus and urogenital papilla in females. Pelvic-fin bases medially in close proximity. Dorsal-fin origin anterior to anal-fin origin in males, anal-fin origin on vertical between base of 2nd dorsal-fin ray; dorsal-fin origin posterior to anal-fin origin in females, on vertical between base of 1st and 3rd anal-fin rays. Dorsal-fin origin between neural spines of vertebrae7 and 9 in males, between neural spines of vertebrae 10 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 8 and 9 in males, between pleural ribs of vertebrae 10 and 12 in females. Dorsal-fin rays 19-21 in males, 14-17 in females; anal-fin rays 19-21 in males, 17-19 in females; caudal-fin rays 26-27 in both sexes; pectoral-fin rays 12-13 in both sexes; pelvic-fin rays 5 in both sexes.

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 8-9; scale rows around caudal peduncle 12. Papillate contact organ on each scale of flank bellow lateral line. Small papillate contact organs on upper surface of three dorsalmost rays of pectoral-fin in males.

Cephalic neuromasts: supraorbital 10-13, parietal 1-2, anterior rostral 1, posterior rostral 1, infraorbital 2 + 19-22, preorbital 3, otic 2, post-otic 3, supratemporal 1, median opercular 1, ventral opercular 2, preopercular16-19, mandibular 10-11, lateral mandibular 6-8, paramandibular 1. One neuromast on center of each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 55% of length; basihyal cartilage about 30% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth absent. Gill-rakers on first branchial arch 2 + 8. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal absent. Total vertebrae 26-27.

Coloration

Males. Sides of body light red, with 12-14 vertical rows of bright blue dots, dots of anterior rows coalesced to form bars. Dorsum light yellowish brown. Venter pink. Sides of head red with four greenish blue bars, one below eye and three on opercular region. Iris yellow, with dark brown bar through center of eye. Dorsal fin red, with light blue dots except on distal portion, forming distinct subdistal row; vertically elongate, alternating blue and black spots on middle of basal portion of fin; narrow light blue line along distal margin. Anal fin yellowish orange, with blue small spots, distal zone red; distinctive subdistal row of small blue spots; narrow light blue line along distal margin. Caudal fin red with blue dots; narrow light blue line along margin, more conspicuous on dorsal and ventral margins. Pectoral reddish hyaline, with blue spots on basal portion.

Females. Side of body light yellowish brown with 10-14 dark gray bars; one to three black blotches on anterocentral part of flank. Dorsum light yellowish brown. Venter light yellowish white. Side of head pale brown with three dark gray bars on opercular region; golden iridescence on opercular region. Iris yellow with brown bar through eye. Fins hyaline.

Distribution

Ribeirão Santana floodplains, upper rio Corumbá drainage, upper rio Paraná basin, central Brazil (Fig. 1).

Habitat

Temporary pools within Mata de Galeria in the Cerrado.