Simpsonichthys zonatus

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 : 40-42

Simpsonichthys zonatus (Costa & Brasil, 1990)

(Fig. 25)

Cynolebias zonatus Costa & Brasil, 1990: 16 ( type locality: Garapuava district, county of Unai , Minas Gerais, Brazil [approximately 18°00’S 46°45’W]; MZUSP 40131 ).

Material examined

Brazil: Estado de Minas Gerais, rio Urucuia drainage, rio São Francisco basin: MZUSP 40131 , holotype, male, 29.4 mm SL; MZUSP 40132 , 1 paratype; MNRJ 11558 , 2 paratypes; UFRJ 142 , 6; UFRJ 279 , 1 (c&s); UFRJ 2123 , 3 (c&s); Garapuava, Municipio de Unai ; G. C. Brasil, 3 Mar. 1989.

Diagnosis

Similar to S. santanae and distinguished from remaining species of the subgenus Simpsonichthys in having minute pelvic fins, with 5 rays (vs. long, with 6 rays in S. marginatus ; pelvic fins absent in S. boitonei , S. parallelus and S. cholopteryx ), and presence of vertically elongated, alternating, blue and black spots (vs. never a similar color pattern). Differs from S. santanae in possessing fewer dorsal-fin rays (15-17 in males and 12-13 in females, vs. 19-21 in males and 14-17 in females) and dorsal-fin origin posterior to anal-fin origin in males (vs. anal-fin origin posterior to dorsal-fin origin).

Description

Morphometric data appear in Table 2. Largest specimen examined 29.4 mm SL, but in aquarium may reach about 35 mm SL. Dorsal profile convex from snout to end of dorsal-fin base, nearly straight on caudal peduncle. Ventral profile gently 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 dorsal portion of head side. Snout blunt. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of both dorsal and anal fins pointed in males, rounded in females. Tip of dorsal and anal fins with short filamentous rays in males, tip of filaments reaching vertical through caudal-fin base. Dorsal-fin rays unbranched. Caudal fin round. Pectoral fins elliptical. Posterior margin of pectoral fins reaching vertical between base of 4th and 6th anal-fin rays in males, and reaching urogenital papilla in females. Pelvic fins minute, bases separated, tip reaching urogenital papilla in males and anus in females. Dorsal-fin origin on vertical through base of 3rd or 4th anal-fin rays in males, through base of 2nd anal-fin ray in females; dorsal-fin origin between neural spines of vertebrae 10 and 11 in males, and neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 8 and 9 in males, and pleural ribs of vertebrae 10 and 11 in females. Dorsal-fin rays 15-17 in males, 12-15 in females; anal-fin rays 19-20 in males, 17-19 in females; caudal-fin rays 26-27; pectoral-fin rays 12; pelvic-fin rays 5.

Frontal squamation E-patterned; E-scales overlapping medially; no scale anterior to G-scale; one small supraorbital scale. Longitudinal series of scales 26-27; transverse series of scales 8; scale rows around caudal peduncle 12. Contact organ on each scale of anteroventral portion of lateral surface of body in males. Minute papillate contact organs on medial surface of first pectoral-fin ray in males.

Cephalic neuromasts: supraorbital 10, parietal 2, anterior rostral 1, posterior rostral 1, infraorbital 2 + 17, preorbital3, otic 2, post-otic 3, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 13, mandibular9, lateral mandibular 6, paramandibular 1. One neuromast on center of each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 45% of length; basihyal cartilage about 20% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 2. Gill-rakers on first branchial arch 2 + 10. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal short. Total vertebrae 26- 27.

Coloration

Males. Sides of body red, with 12-15 bright greenish blue bars, posterior bars narrower and interrupted, forming vertical rows of small spots; ventral portion of interspace between anterior bright bars black in older specimens. Sides of head red, with four greenish blue bars, one below eye and three on opercular region. Iris yellow, with dark brownish red bar through center of eye. Dorsal fin red, with alternating black and light blue elongated spots on basal portion, and row of greenish blue round spots along subdistal region. Basal half of anal fin orange, with greenish blue elliptical spots; distal half of anal fin red, with row of blue round spots along subdistal region. Caudal fin red, with small greenish blue round spots; narrow blue margin. Pectoral and pelvic fins red, with blue base.

Females. Sides of body pale brown, with 10-15 dark brownish gray bars; one black blotch on anterocentral part of flank. Venter light yellowish white. Sides of head pale brown, with three dark brownish gray bars on opercular region; golden iridescence on opercular region. Iris yellow, with brown bar through eye. Unpaired fins hyaline, with faint gray spots on basal portion. Paired fins hyaline.

Distribution

Upper rio Urucuia drainage, rio São Francisco basin, Estado de Minas Gerais, Brazil (Fig. 4).

Habitat

Temporary pools within Mata de Galeria in the Cerrado.