Simpsonichthys virgulatus, Wilson J. E. M. Costa & Gilberto C. Brasil, 2006

Wilson J. E. M. Costa & Gilberto C. Brasil, 2006, Three new species of the seasonal killifish genus Simpsonichthys, subgenus Hypsolebias (Teleostei: Cyprinodontiformes: Rivulidae) from the rio Paracatu drainage, rio São Francisco basin, Brazil., Zootaxa 1244, pp. 41-55 : 43-46

Simpsonichthys virgulatus , new species

(Figs. 1-2)

Material examined

Holotype. UFRJ 6336, male, 41.5 mm SL; Brazil: Estado de Minas Gerais: Município de Unaí, temporary lagoon about 7 km from ribeirão Entre Rios, rio Paracatu drainage, rio São Francisco basin, about 16º49’30”S 46º30’00”W, altitude about 530 m; G. C. Brasil, 26 May 2005.

Paratypes. UFRJ 6337, 10 males, 39.2-52.7 mm SL, 23 females, 28.9-33.9 mm SL ; UFRJ 6338, 3 males, 39.2-43.7 mm SL, 3 females, 28.8-32.7 mm SL (c&s) ; MCP 39931, 2 males, 40.2-42.6 mm SL, 3 females, 29.1-31.8 mm SL; all collected with holotype .

Diagnosis

Similar to S. auratus and S. trilineatus and distinguished from all other congeners in having the following combination of characters: frontal squamation A-patterned (vs. E- patterned), anterior portion of flank golden with dark brown to black blotches in males (vs. never a similar color pattern), and dark gray spots on the entire flank in females (vs. never a similar color pattern). Distinguished from S. auratus and S. trilineatus by having more black blotches on anterior portion of flanks in males (7-13, vs. 3-5), dark brown bars on the whole caudal peduncle in males (vs. entire caudal peduncle purplish brown in S. auratus , and caudal peduncle light brown with three purplish brown stripes in S. trilineatus ), and pectoral fins hyaline in males (vs. ventral portion of pectoral fin pale red).

Description

Morphometric data appear in Table 1. Males larger than females, the largest male examined 52.7 mm SL; largest female 33.9 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 deep, compressed, greatest body depth at level of pelvic-fin base. Snout blunt. Urogenital papilla cylindrical and short in males; urogenital papilla protuberate in females, posterior border slightly overlapping anterior portion of anal fin, urogenital opening transverse.

Tip of both dorsal and anal fins pointed in males; tip of dorsal fin slightly pointed, and tip of anal fin rounded in females; dorsal and anal fins short in females. Short filamentous rays on tip of both dorsal and anal fins in males, tip of filaments reaching vertical through caudal-fin base. Anterior and posterior rays of dorsal-fin rays, including rays on tip of fin, unbranched; median rays branched. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of pectoral fins reaching vertical between base of 2nd and 4th anal-fins ray in males, between pelvic-fin base and anus in females. Tip of each pelvic fin reaching between base of 2nd and 3rd anal-fin rays in males, between urogenital papilla and base of 2nd anal-fin ray in females. Pelvic-fin bases medially in contact. Dorsal-fin origin anterior to anal-fin origin in males, anal-fin origin on vertical between base of 2nd and 3rd dorsal-fin rays; dorsal-fin origin posterior to anal-fin origin in females, on vertical between base of 2nd and 3rd anal-fin rays. Dorsal-fin origin between neural spines of vertebrae 7 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 9 and 10 in females. Dorsal-fin rays 20-21 in males, 14-16 in females; anal-fin rays 19-20 in males, 16-18 in females; caudal-fin rays in both sexes 25-27; pectoral-fin rays in both sexes 12-13; pelvic-fin rays in both sexes 5-6.

Scales large, cycloid. Body and head entirely scaled, except on ventral surface of head. Trunk squamation extending slightly onto middle of anal-fin base. Scales extending onto anterior fifth of caudal fin. Frontal squamation A-patterned; E-scales slightly overlapping medially; row of scales anterior to H-scale, just posterior to rostral regions; single supraorbital scale. Longitudinal series of scales 26-28; transverse series of scales 8-9; scale rows around caudal peduncle 12. Minute contact organ on each scale of anteroventral portion of flank in males. Small papillate contact organs on upper surface of dorsal-most ray of pectoral-fins in males.

Cephalic neuromasts: supraorbital 11-13, parietal 3, anterior rostral 1, posterior rostral 1, infraorbital 2 + 18-19, preorbital 3, otic 2, post-otic 1-3, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 15-16, mandibular 12, lateral mandibular 5-7, paramandibular 1. One neuromast on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, the greatest width about 55 % of length; basihyal cartilage about 15 % of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 2-3. Gill-rakers on first branchial arch 3 + 9. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 27-28.

Coloration

Males: Sides of body golden, with rounded dark brown to black rounded blotches on anterior portion of flanks and 4-7 dark brown bars on posterior portion of flanks; vertical rows of light green dots along whole flank, sometimes coalesced to form vertical lines, alternating with narrow dark orangish brown stripes on anterior portion of flanks. Dorsum light brown, venter yellowish white. Sides of head light brown to greenish golden on opercular region. Scale margins of posterodorsal portion of head side dark orangish brown. Iris light yellow, with dark reddish brown bar through center of eye. Unpaired fins dark yellowish brown, with light green dots; rows of greenish blue short vertical lines along distal margin of dorsal fin. Pelvic fins yellowish brown. Pectoral fins hyaline.

Females: Sides of body light yellowish brown, with dark gray spots; spots above analfin base usually elongate, forming short bars; 3-4 spots on anterocentral portion of flank black, often coalesced to form stripe. Dorsum pale brown, venter pale golden. Opercular region greenish golden. Iris light yellow, with gray bar through center of eye. Unpaired fins hyaline, with black small spots on basal region; small light blue spot on posterior margin of anal fin, just posterior to fin base. Paired fins hyaline.

Distribution

Known only from the type locality, ribeirão Entre Ribeiros floodplains, rio Paracatu drainage, rio São Francisco basin, Unaí, Estado de Minas Gerais, Brazil (Fig. 3).

Habitat

Simpsonichthys virgulatus was collected in an isolated seasonal lagoon, with an area about 3,000 m2, and maximum depth about 0.8 m. The water was tea-colored, pH 7.9-8.1, temperature of the air 30.5°C, and temperature of the water 23.1°C, at 2:00 PM. The region is an area with typical savannah vegetation, the Cerrado. No other fishes were found there. This locality is about 15 km (in a straight line) from the mutual type localities of S. fasciatus and S. gibberatus (see below).

Etymology

From the Latin virgulatus (with stripes of different colors), in reference to the male color pattern.