Simpsonichthys igneus

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 : 106-108

Simpsonichthys igneus Costa, 2000

(Figs. 67)

Simpsonichthys igneus Costa, 2000: 10 ( type locality: temporary pool close to Igarite [22 km N of Igarite ], rio Sao Francisco basin , Estado da Bahia, Brazil [11°28’8.4”S 43°17’13.4”W; altitude 433 m]; holotype: MZUSP 56254 ).

Material examined

Brazil: Estado da Bahia, rio São Francisco basin: MZUSP 56254 , holotype, male, 42.3 mm SL; MZUSP 56255 , 8 paratypes; MCP 23669 , 8 paratypes; UFRJ 4857 , 100 paratypes; UFRJ 5190 , 15 paratypes; UFRJ 5191 , 6 paratypes; UFRJ 5192 , 10 paratypes; UFRJ 5193 , 10 paratypes; temporary pool 22 km N from Igarite ; W. J. E. M. Costa, A. C. L. H. Bacellar, F. Pupo & E. Araujo, 06 May 1999. UFRJ 4872 , 33 paratypes; 40 km N of Igarité; same collectors and date. UFRJ 4868 , 28 paratypes; UFRJ 4870 , 62 paratypes; UFRJ 4869 , 10 paratypes (c&s); 27.5 km N of Igarité; same collectors and date. UFRJ 4877 , 14 paratypes; 21.5 km N from Igarité; same collectors and date. UFRJ 5417 , 7; same locality as for holotype ; W. J. E. M. Costa, C. P. Bove & B. B. Costa, 26 Jan. 2002.

Diagnosis

Distinguished from other species of the S. antenori group by possessing seven pelvic-fin rays (vs. six) and bars of the flank inconspicuous in live males, poorly visible in preserved specimens (vs. bars visible in both in live and preserved individuals).

Description

Morphometric data appear in Table 6. Largest specimen examined 51.4 mm SL. Dorsal profile slightly concave on head, convex from nape to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile convex from lower jaw to end of anal-fin base, about straight on caudal peduncle. Eye positioned on dorsolateral portion of side of head. Snout blunt. Body deep, compressed, greatest body depth at level of pelvic-fin bases. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of dorsal fin pointed in males, rounded to slightly pointed in females; tip of anal fin pointed in males, rounded in females. Tip of dorsal and anal fins with filamentous rays in males, tips reaching beyond posterior border of caudal fin. Caudal fin subtruncate in males, round in females. Pectoral fins elliptical. Posterior margin of each pectoral fin reaching vertical through base of 7th or 8th anal-fin ray in males, and 1st or 2nd anal-fin ray in females. Tip of each pelvic fin reaching base of 3rd or 4th anal-fin ray in males and 1st anal-fin ray in females. Pelvic-fin bases medially united. Dorsal-fin origin in vertical through base of 2nd anal-fin ray in males, and base of 5th or 6th anal-fin ray in females; dorsal-fin origin between neural spines of vertebrae 8 and 9 in males and neural spines of vertebrae 10 and 13 in females. Anal-fin origin between pleural ribs of vertebrae7 and 9 in males, and pleural ribs of vertebrae 9 and 10 in females. Dorsal-fin rays 20-24 in males, 15- 19 in females; anal-fin rays 21-25 in males, 20-24 in females; caudal-fin rays 23-25; pectoral-fin rays 13-14; pelvic-fin rays 7.

Frontal squamation E-patterned; E-scales overlapping medially; no scales anterior to H-scale; two supraorbital scales. Longitudinal series of scales 29-30; transverse series of scales 14; scale rows around caudal peduncle 16. One to three minute contact organs on each scale of anteroventral portion of flank in males, sometimes inconspicuous. Small papillate contact organs on inner surface of three dorsalmost rays of pectoral fins in males.

Cephalic neuromasts: supraorbital 14-18, parietal 3, anterior rostral 1, posterior rostral with one lateral neuromast and middle neuromast, infraorbital 2 + 19-25, preorbital 3, otic 1-2, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 16-18, mandibular 13-15, lateral mandibular 4-5, paramandibular1. One neuromast on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 70-75% of length; basihyal cartilage about 25% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 5-6. Gill-rakers on first branchial arch 4 + 13. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 28-30.

Coloration

Males. Sides of body light purplish gray, with white dots. In life, body bars not conspicuous in adult specimens, but preserved specimens with 13-18, narrow, straight faint gray bars on flank. Opercular region pale greenish golden. Iris light yellow, with dark purplish gray bar. Dorsal fin dark purplish pink on anterior two thirds to yellow on posterior portion, with white dots; dorsal-fin filaments black. Anal fin greenish yellow, with bluish white dots; subdistal zone reddish orange; blue spot on fin tip; black distal stripe; anal-fin filaments black. Caudal fin yellow, with white dots, and metallic light blue stripe on posterior edge of fin. Pectoral fins hyaline. Pelvic fins reddish orange, each with a black tip.

Females. Sides of body light gray, with 13-18 dark gray bars; venter pale golden; 1-4 rounded black blotches on anterocentral portion of flank; 1-15 irregularly arranged rounded black blotches on caudal peduncle. Opercular region pale golden. Iris light yellow, with gray bar through center of eye. Unpaired fins hyaline, with faint, longitudinally elongated gray spots; small, iridescent blue spot on posterior portion of anal fin close to caudal peduncle. Paired fins hyaline.

Distribution

Floodplains of middle portion, left bank, of the rio São Francisco, between Barra and Igarité, Estado da Bahia, northeastern Brazil (Fig. 1).

Habitat

Temporary pools in the Caatinga.