Simpsonichthys multiradiatus

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 : 126-128

Simpsonichthys multiradiatus (Costa & Brasil, 1994)

(Figs. 78)

Cynolebias multiradiatus Costa & Brasil, 1994a: 1 ( type locality: temporary pool in Brejinho de Nazare , Tocantins, Brazil [approximately 11°00’S 48°40’W; altitude 247 m]; holotype: MNRJ 12519 ).

Material examined

Brazil: Estado do Tocantins, rio Tocantins drainage, rio Amazonas basin: MNRJ 12519 , holotype, male, 32.9 mm SL; MNRJ 12520 , 9 paratypes; MZUSP 46080 , 8 paratypes; UFRJ 2074 , 7 paratypes (c&s); UFRJ 2075 , 6 paratypes; UFRJ 2076 , 8 paratypes; UFRJ 2097 , 63; UMMZ 230858 , 12; MCZ 138938 , 2; temporary pool in Brejinho de Nazare ; W. J. E. M. Costa, G. C. Brasil & C. M. C. Santos, 15 Feb. 1994.

Diagnosis

Distinguished from all other species of the S. flammeus group by having numerous rays in dorsal and anal fins (dorsal-fin rays 25-28 in males, 17-21 in females, vs. 18-23 in males, 13-18 in females; anal-fin rays 23- 28 in males, 21-24 in females, vs. 20-24 in males, 18-22 in females).

Description

Morphometric data appear in Table 7. Largest specimen examined 46.4 mm SL. Dorsal profile concave on head, convex from nape to end of dorsal-fin base, nearly 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 and anal fins pointed in males, rounded in females; median anal-fin rays long in females, anal fin spatula-shaped. Tip of dorsal and anal fins with filamentous rays in males, tips reaching vertical through center of caudal fin. Caudal fin subtruncate in males, round in females. Pectoral fins elliptical. Posterior margin of pectoral fin reaching vertical between base of 3rd and 7th anal-fin ray in males, and between urogenital papilla and base of 2nd anal-fin ray in females. Tip of each pelvic fin reaching base of 1st anal-fin ray in males and reaching urogenital papilla in females. Pelvic-fin bases medially in close proximity. Dorsalfin origin in vertical between pelvic-fin base and anus in males, and through urogenital papilla in females. Dorsal-fin origin between neural spines of vertebrae 5 and 7 in males, and neural spines of vertebrae 8 and 10 in females. Anal-fin origin between pleural ribs of vertebrae 7 and 8 in males, and pleural ribs of vertebrae 8 and 9 in females. Dorsal-fin rays 25-28 in males, 17-21 in females; anal-fin rays 23-28 in males, 21-24 in females; caudal-fin rays 23-26; pectoral-fin rays 12-13; pelvic-fin rays 6.

Frontal squamation usually E-patterned, rarely A or F-patterned; E-scales overlapping medially; no row of scales anterior to H-scale; two small supraorbital scales. Longitudinal series of scales 26-27; transverse series of scales 11-12; scale rows around caudal peduncle 14. 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 15-18, parietal 2-3, anterior rostral 1, posterior rostral 1, infraorbital 2 + 25-27, preorbital 4, otic 2, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 2-3, preopercular16-19, mandibular 14, lateral mandibular 4-5, paramandibular 1. One or two neuromasts on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 65% of length; basihyal cartilage about 40% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 3. Gill-rakers on first branchial arch 5 + 12. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 26- 28.

Coloration

Males. Sides of body bright blue, with 12-14 reddish gray bars. Venter pale orange. Posterolateral portion of head red, with blue spot on center of each scale. Opercular region greenish blue. Iris light yellow, with dark brown bar. Dorsal fin brownish red, with small round blue spots; sometimes oblique short brownish red stripes on posterior portion of fin; anterobasal portion of fin with elongated spots, parallel to fin rays. Anal fin light blue, with 6-7 brownish red bars. Caudal fin light blue, with 5-6 brownish red bars and bright blue distal border. Pectoral fins hyaline. Pelvic fins reddish brown.

Females. Sides of body pale brownish gray, with faint gray bars; one or two black spots on anterocentral portion of flanks. Venter pale golden. Opercular region pale green. 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

Middle rio Tocantins floodplains, Estado do Tocantins, central Brazil (Fig. 4).

Habitat

Temporary pools in the Cerrado.