Simpsonichthys gibberatus

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 : 72-74

Simpsonichthys gibberatus Costa & Brasil, 2006

(Figs. 47-48)

Simpsonichthys gibberatus Costa & Brasil, 2006: 50 ( type locality: Unai , temporary pool about 2 km from the right bank of rio Preto, rio Paracatu drainage, rio Sao Francisco basin , about 16°41’30”S 46°30’00”W, altitude about 550 m, Estado de Minas Gerais, Brazil; holotype: UFRJ 6373 ).

Material examined

Brazil: Estado de Minas Gerais, rio Paracatu drainage, rio São Francisco basin: UFRJ 6373 , holotype, male, 27.9 mm SL; UFRJ 6374 , 11 paratypes; UFRJ 6375 , 6 paratypes (c&s); MCP 39933 , 4 paratypes; Brazil: Estado de Minas Gerais: Unai , temporary pool about 2 km from the right bank of rio Preto, rio Paracatu drainage, rio Sao Francisco basin ; G. C. Brasil, 14 Feb. 2006.

Diagnosis

Differs from all congeners by a pronounced convexity on dorsal profile between posterior portion of head and anterior portion of trunk in females, greatest body depth at level of posterior margin of opercle (vs. at level of pelvic-fin base).

Description

Morphometric data appear in Table 4. Largest specimen examined 27.9 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 in male, at level of posterior margin of opercle in females. 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 and with short filamentous rays in males, tip of longest filament reaching vertical through caudal-fin base. Dorsal and anal fins rounded in females, anal fin slightly lengthened. Most dorsal-fin rays unbranched. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of each pectoral fin reaching vertical between base of 6th and 8th anal-fins ray in males, and base of 3rd anal-fins ray in females. Tip of each pelvic fin reaching between base of 3rd and 4th anal-fin rays in males, reaching urogenital papilla in females. Pelvic-fin bases medially in contact. Dorsal-fin origin anterior to anal-fin origin, anal-fin origin on vertical between base of 4th and 5th dorsal-fin rays in males, between base of 1st and 3rd dorsal-fin rays in females. Dorsal-fin origin between neural spines of vertebrae 6 and 7 in males, between neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 7 and 9 in males, between pleural ribs of vertebrae 10 and 12 in females. Dorsal-fin rays 21-26 in males, 15-17 in females; anal-fin rays 18-20 in males, 16-18 in females; caudal-fin rays 27-29; pectoral-fin rays 13-14; pelvic-fin rays 6.

Frontal squamation A-patterned; E-scales overlapping medially; no row of scales anterior to H-scale; two small supraorbital scales. Longitudinal series of scales 25-27; transverse series of scales 8-9; scale rows around caudal peduncle 12. Prominent contact organ on each scale of anteroventral portion of flanks in males. No contact organs on pectoral fins.

Cephalic neuromasts: supraorbital 13-15, parietal 2-3, anterior rostral 1, posterior rostral 1, infraorbital 2-3 + 17-23, preorbital 3, otic 2, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 1-2, preopercular plus mandibular 27-33, lateral mandibular 5-9, paramandibular 1. One neuromast on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 70% of length; basihyal cartilage about 25% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 1-2. Gill-rakers on first branchial arch 2 + 9. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 27- 28.

Coloration

Males. Sides of body light golden, with 9-11 light brown bars and horizontal series of small bright greenish blue spots; often dark gray to black spot on anterocentral portion of flanks. Dorsum light brown, venter yellowish white. Sides of head light golden to reddish brown on scales margins of dorsoposterior portion of head, with small greenish blue spots on center of scales; infraorbital region light golden. Iris light yellow, with reddish brown bar through center of eye. Unpaired fins dark gray to almost black, with small light blue spots; pale blue line on posterior margin of caudal fin. Pelvic fins dark gray. Pectoral fins hyaline.

Females. Sides of body light brownish gray, with 11-13 pale gray bars and 1 or 2 round black spot on anterocentral portion of flanks. Dorsum light brownish gray, venter light gray. Opercular region pale golden. Iris light yellow, with gray bar through center of eye. Fins hyaline.

Distribution

Middle rio Preto drainage, a part of rio Paracatu drainage, rio São Francisco basin, Unaí, Estado de Minas Gerais, Brazil (Fig. 1).

Habitat

Temporary pools in the Cerrado.