Simpsonichthys adornatus

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 : 85-87

Simpsonichthys adornatus Costa, 2000

(Figs. 55-56)

Simpsonichthys adornatus Costa, 2000: 9 ( type locality: temporary pool near Sitio do Mato, rio Sao Francisco basin , Estado da Bahia, Brazil [13º00’46.1”S 43º28’50.0”W; altitude 463 m]; holotype: MZUSP 54563 ).

Material examined

Brazil: Estado da Bahia, rio São Francisco basin floodplains: MZUSP 54563 , holotype, male, 44.5 mm SL; UFRJ 4805 , 18 paratypes; UFRJ 4806 , 1 paratype; temporary pool 8 km N of Sitio do Mato ; W. J. E. M. Costa, F. M. Pupo & E. S. Araujo, 12 Feb. 1999. MZUSP 54564 , 10 paratypes; MCP 22262 , 20 paratypes; UFRJ 5188 , 20 paratypes; UFRJ 5189 , 10 paratypes; UFRJ 4807 , 8 paratypes (c&s); 1.5 km N from the type locality ; same collectors, 15 Feb. 1999.

Diagnosis

Readily distinguished from all other aplocheiloids by the possession of numerous dorsal-fin rays in males (28-32, vs. 5-25). Probably related to the high number of dorsal-fin rays, it also differs from all other rivulids by possessing the dorsal-fin origin inserted near the nape, between neural spines of third and fourth vertebrae (vs. between neural spines of vertebrae 6 and 20). Differs from all other species of Simpsonichthys by having the flanks light blue, with longitudinal rows of minute bluish white spots in males (vs. never a similar color pattern), well defined horizontal rows of small dark brown spots on flanks in females, and two rounded black spots vertically arranged on posterior portion of caudal peduncle in females (vs. never similar color patterns).

Description

Morphometric data appear in Table 5. Largest specimen examined 45.1 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 side of head. Snout blunt. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of dorsal fin pointed in males, rounded in females; tip of anal fin rounded in both sexes. Short filamentous ray on tip of dorsal fin in males, reaching vertical through middle of caudal fin; filaments absent in anal fin. Dorsal-fin rays unbranched. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of each pectoral fin reaching vertical through base of 5th anal-fin ray in males, and between pelvic-fin base and urogenital papilla in females. Tip of each pelvic fin reaching base of 4th anal-fin ray in males and base of 1st analfin ray in females. Pelvic-fin bases in close proximity. Dorsal-fin origin anterior to anal-fin origin in males, anal-fin origin on vertical through base of 5th dorsal-fin ray; dorsal-fin origin posterior to anal-fin origin in females, on vertical through base of 3rd or 4th anal-fin ray. Dorsal-fin origin between neural spines of vertebrae 3 and 5 in males, and neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 6 and 7 in males, and pleural ribs of vertebrae 8 and 10 in females. Dorsal-fin rays 28-32 in males, 14-19 in females; anal-fin rays 21-24 in males, 18-22 in females; caudal-fin rays 22-24; pectoral-fin rays 12-13; pelvic-fin rays 5-6.

Frontal squamation E-patterned; E-scales overlapping medially; no row of scales anterior to G-scale; supraorbital scales 2. Longitudinal series of scales 27-29; transverse series of scales 10; scale rows around caudal peduncle 12. Contact organ on each scale of flank and ventral portion of opercle in males. Small papillate contact organs on inner surface of three dorsalmost rays of pectoral fins in males.

Cephalic neuromasts: supraorbital 14-17, parietal 2, anterior rostral 1, posterior rostral 1, infraorbital 2 + 23-25, preorbital 3, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 14-18, mandibular 12-13, lateral mandibular 5, paramandibular 1. One neuromast on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 50% of length; basihyal cartilage about 25% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 1-3. Gill-rakers on first branchial arch 2 + 9. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 27- 29.

Coloration

Males. Sides of body light blue to purplish blue, with longitudinal rows of white dots, anterior dots vertically elongated; faint gray bars alternating with pale red bars on anterior portion of flanks. In preserved specimens, about 15 faint gray bars on flank. Sides of head light blue, opercular region bright greenish blue; posterodorsal scales with red margin. Iris pale yellow with black bar through center of eye. Unpaired fins dark bluish gray, with bluish white dots, basal region yellowish gray; anterior third of dorsal fin with bright blue oblique lines. Pelvic fins dark yellowish gray. Pectoral fins hyaline.

Females. Sides of body light purplish gray, golden on venter, with horizontal rows of small, dark brownish gray spots, sometimes coalesced to form horizontal stripes; spots on anterocentral portion of flanks black. Two round black blotches, vertically arranged, on posterior portion of caudal peduncle. Iris light yellow, with dark gray bar through center of eye. Opercular region light blue, with small gray spots. Unpaired fins and pelvic fins hyaline, with small dark brownish gray spots; small light blue spot on posterior margin of anal fin, just posterior to fin base. Pectoral fins hyaline.

Distribution

Floodplains of middle rio São Francisco, Estado da Bahia, northeastern Brazil (Fig. 4).

Habitat

Temporary pools in the Caatinga.