Simpsonichthys delucai

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 : 120-122

Simpsonichthys delucai Costa, 2003

(Figs. 74-75)

Simpsonichthys delucai Costa, 2003: 49 ( type locality: temporary pool near the city of Urucuia, rio Urucuia floodplains, rio Sao Francisco basin , approximately 16°08’S 45°45’W, altitude 498 m, Estado de Minas Gerais, Brazil; holotype: MZUSP 46082 ).

Material examined

Brazil: Estado de Minas Gerais, rio Urucuia drainage, rio São Francisco basin: MCP 28572 , holotype, male, 21.4 mm SL; MCP 28573 , 1 paratype; UFRJ 5426 , 17 paratypes; UFRJ 5427 , 4 paratypes (c&s); temporary pool near the city of Urucuia , approximately 16°08’S 45°45’W; altitude 498 m; A. C. De Luca & D. H. B. Padrão, 27 Jan. 2001.

Diagnosis

Similar to S. alternatus and S. fasciatus and distinguished from the remaining species of the S. flammeus group by possessing a distal red bar on caudal fin in males (vs. broad metallic blue bar), a red distal stripe on anal fin in males (vs. no distinctive distal stripe), short to minute filamentous rays on tip of dorsal fin in males (vs. long filaments), and anal fin rounded in males (vs. pointed); differs from S. alternatus and S. fasciatus by having dorsal fin rounded to slightly pointed in males (vs. pointed), dorsal fin reddish brown, with light greenish yellow spots and three or four brown bars restricted to posterobasal portion in males (vs. six to eight bars through whole fin), and dark brown to black bars on flank in males (vs. reddish gray bars).

Description

Morphometric data appear in Table 7. Largest specimen examined 22.1 mm SL, but in aquarium reaching at least about 28 mm SL. Dorsal profile slightly concave on head, convex from nape to end of dorsal-fin base, about straight on caudal peduncle. Ventral profile convex from lower jaw to end of anal-fin base, approximately straight on caudal peduncle. Body moderately deep, compressed, greatest body depth at level of pelvic-fin base. Eye positioned on dorsolateral portion of side of head. Snout blunt. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of dorsal rounded to slightly pointed in males, rounded in females; anal fin rounded in both sexes; median anal-fin rays long in females, anal fin spatula-shaped. Minute filamentous rays on posterodistal border of dorsal fin in males, tips reaching vertical through caudal peduncle; no filamentous rays on anal fin. Caudal fin subtruncate in males, round in females. Pectoral fins elliptical. Posterior margin of pectoral fins reaching vertical between base of 4th and 6th anal-fin ray in males, and reaching anus in females. Tip of each pelvic fin reaching between base of 2nd and 4th anal-fin ray in males, and reaching urogenital papilla in females. Pelvic-fin bases medially in close proximity. Dorsal-fin origin in vertical through base of 3rd anal-fin ray in males, and base of 4th anal-fin ray in females. Dorsal-fin origin between neural spines of vertebrae 8 and 10 in males, and neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 7 and 9 in males, and pleural ribs of vertebrae 8 and 9 in females. Dorsal-fin rays 18-22 in males, 13-16 in females; anal-fin rays 22-23 in males, 18-20 in females; caudal-fin rays 23-24; pectoral-fin rays 12-13; pelvic-fin rays 6.

Frontal squamation E-patterned; E-scales overlapping medially; no row of scales anterior to G-scale; two small supraorbital scales. Longitudinal series of scales 25-26; transverse series of scales 8; scale rows around caudal peduncle 12. Contact organ on each scale of ventral portion of lateral surface of body in males. Small papillate contact organs on inner surface of three dorsalmost rays of pectoral fins in males. Cephalic neuromasts: supraorbital 12-13, parietal 3, anterior rostral 1, posterior rostral 1, infraorbital 2-3 + 19, preorbital 3, otic 2, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 14- 15, mandibular 11-12, lateral mandibular 5, paramandibular 1. One or two neuromasts on 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 3. Gill-rakers on first branchial arch 3 + 11. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 26.

Coloration

Males. Sides of body bright brownish yellow with 9-10 dark brown to black bars slightly posteriorly inclined. Opercular region pale greenish golden. Iris light yellow, with dark brown bar. Dorsal fin light greenish yellow with 3-4 short brown bars on posterobasal portion, brownish red with greenish yellow spots on distal portion. Anal fin light greenish yellow with 5-6 brown oblique bars and brownish red distal stripe. Caudal fin light greenish yellow with 4-5 brown bars and red distal border. Pectoral fins hyaline. Pelvic fins reddish brown, with greenish yellow base.

Females. Sides of body light yellowish gray, with one or two black spots on anterocentral portion of flank; sometimes faint gray bars on caudal peduncle. Opercular region pale greenish golden. Iris light yellow, with gray bar. Unpaired fins hyaline, with faint spots; small, iridescent blue spot on posterior portion of anal fin close to caudal peduncle. Paired fins hyaline.

Distribution

Rio Urucuia floodplains, rio São Francisco basin, Estado de Minas Gerais, Brazil (Fig. 4).

Habitat

Temporary pools in the Cerrado.