Simpsonichthys virgulatus,

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: 75-77

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Simpsonichthys virgulatus


Simpsonichthys virgulatus  Costa & Brasil, 2006

(Figs. 49-50)

Simpsonichthys virgulatus  Costa & Brasil, 2006: 43 ( type locality: temporary lagoon about 7 km from ribeirao Entre Rios, rio Paracatu drainage, rio Sao Francisco basin , about 16º49’30”S 46º30’00”W, altitude about 530 m, Municí- de Unaí, Estado de Minas Gerais, Brazil; holotype: UFRJ 6336GoogleMaps  ).

Material examined

Brazil: Estado de Minas Gerais, rio Paracatu drainage, rio São Francisco basin: UFRJ 6336, holotype, male, 41.5 mm SL; UFRJ 6337, 33 paratypes; UFRJ 6338, 6 paratypes (c&s); MCP 39931, 5 paratypes; Brazil: Estado de Minas Gerais: Municipio de Unai , temporary lagoon about 7 km from ribeirao Entre Rios, rio Paracatu drainage, rio Sao Francisco basin ; G. C. Brasil, 26 May 2005. 


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


Morphometric data appear in Table 4. Largest specimen examined 52.7 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. 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; tip of dorsal fin slightly pointed and tip of anal fin rounded in female; 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 each pectoral fin 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 analfin 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; analfin rays 19-20 in males, 16-18 in females; caudal-fin rays 25-27; pectoral-fin rays 12-13; pelvic-fin rays 5-6.

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 flanks in males. Small papillate contact organs on upper surface of dorsalmost ray of pectoralfins 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, preopercular15-16, mandibular 12, lateral mandibular 5-7, paramandibular 1. One neuromast on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, 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.


Males. Side of body golden, with rounded dark brown to black rounded blotches on anterior portion of flank and 4-7 dark brown bars on posterior portion of flanks; vertical rows of light green dots along entire flanks, sometimes coalesced and forming 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 on posterodorsal portion of sides of head dark orangish brown. Iris light yellow, with dark reddish brown bar through center of eye. Unpaired fins dark yellowish brown, with light green dots; row 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 anal-fin base usually elongate, forming short bars; 3-4 spots on anterocentral portion of flanks 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.


Ribeirão Entre Ribeiros floodplains, rio Paracatu drainage, rio São Francisco basin, Unaí, Estado de Minas Gerais, Brazil (Fig. 1).


Temporary pools in the Cerrado.