Simpsonichthys rufus

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 : 59-61

Simpsonichthys rufus Costa, Nielsen & De Luca, 2001

(Figs. 36)

Simpsonichthys rufus Costa, Nielsen & De Luca, 2001: 29 ( type locality: temporary pool near riacho do Barro, Ibiai , near rio Sao Francisco , Estado de Minas Gerais, Brazil [approximately 17°10’S 45°00’W; altitude about 490 m]; holotype: MZUSP 61234 ).

Material examined

Brazil: Estado de Minas Gerais, rio São Francisco basin: MZUSP 61234 , holotype, male, 30.0 mm SL; MZUSP 61235 , 1 paratype; UFRJ 5110 , 3 paratypes; UFRJ 5111 , 2 paratypes (c&s); UFRJ 5114 , 10; temporary pool close to riacho do Barro, Ibiai ; D. T. B. Nielsen & N. Nielsen, 9 Feb. 1997 . UFRJ 5112 , 3 paratypes; UFRJ 511 , 4 paratypes (c&s); temporary pool close to the type locality ; same collectors and date as holotype .

Diagnosis

Distinguished from all other species of the S. notatus group by having anal-fin origin between pleural ribs of vertebrae 9 and 10 in males (vs. between pleural ribs of vertebrae 7 and 9); also distinguished from all congeners of the S. notatus group by the combination of black blotch on anterocentral portion of each flank absent in males (vs. present) and absence of elongated bright blue and black spots on dorsal-fin base in males (vs. presence).

Description

Morphometric data appear in Table 4. Largest specimen examined 33.6 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 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 dorsal and anal fins pointed in males; dorsal fin rounded to gently pointed and anal fin rounded in females; long filamentous rays on tip of dorsal and anal fins in males, tip reaching posterior half of caudal fin. Dorsal-fin rays unbranched. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of each pectoral fin reaching vertical through base of 6th anal-fin ray in males, and reaching urogenital papilla in females. Tip of each pelvic fin reaching base of 4th anal-fin ray in males and 1st anal-fin ray in females. Pelvic-fin bases in close proximity. Dorsal-fin origin on vertical approximately through anal-fin origin in males, slightly anterior to anal-fin origin in females; dorsal-fin origin between neural spines of vertebrae 8 and 9 in males, between neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 9 and 10 in males, between pleural ribs of vertebrae 11 and 12 in females. Dorsal-fin rays 21-23 in males, 15-17 in females; anal-fin rays 20-22 in males, 17-18 in females; caudal-fin rays 27-28; pectoral-fin rays 13-14; pelvic-fin rays 6.

Frontal squamation A-patterned; E-scales medially overlapped; no scale anterior to H-scale; supraorbital scales 1-2. Longitudinal series of scales 27-28; transverse series of scales 9-10; scale rows around caudal peduncle 12. Contact organ on each scale of anteroventral portion of flanks in males. Small papillate contact organs on inner surface of dorsalmost ray of each pectoral fin in males.

Cephalic neuromasts: supraorbital 12-15, parietal 3-5, anterior rostral 1, posterior rostral 1, infraorbital 2 + 19-21, preorbital 2-4, otic 1-2, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 2, preopercular12, mandibular 13, lateral mandibular 7, paramandibular 1. One neuromast on center of each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 65% of length; basihyal cartilage about 25% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 2-4. Gill-rakers on first branchial arch 3 + 10. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 28-29.

Coloration

Males. Sides of body and head yellow ochre, with 10-11 dark red crimson bars and bright blue dots. Sides of head yellow ochre, with small blue spots on opercular region, dorsoposterior scales with red crimson edge; red crimson bar on preopercle. Iris yellow, with dark red crimson bar through center of eye. Dorsal fin yellow ochre, anterior portion and distal border pale pink, with small round light blue spots; series of short vertical lines along distal border. Anal fin yellow ochre, anterior portion pale pink, with dark gray oblique bars. Dorsal and anal fin filaments black. Caudal fin orange, pale pink close to margins, with small round light blue spots; narrow bright blue margin. Pelvic fins pale pink. Pectoral fins hyaline. Females. Sides of body light gray, with gray spots, sometimes coalescent forming bars; venter pale golden; one to three rounded black blotches on anterocentral portion of flanks. Opercular region pale greenish golden. Iris light yellow, with gray bar through center of eye. Unpaired fins hyaline, with faint gray spots on basal region; small light blue spot on posterior margin of anal fin, just posterior to fin base. Paired fins hyaline.

Distribution

Rio do Barro floodplains, middle rio São Francisco basin, Estado de Minas Gerais, Brazil (Fig. 1).

Habitat

Temporary pools in the Cerrado.