Simpsonichthys flavicaudatus,

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: 108-110

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Simpsonichthys flavicaudatus


Simpsonichthys flavicaudatus  (Costa & Brasil, 1990)

(Fig. 68)

Cynolebias flavicaudatus  ZBK  Costa & Brasil, 1990: 18 ( type locality: vicinity of Lagoa Grande, county of Santa Maria da Boa Vista , Pernambuco, Brazil [approximately 9°00’S 40°20’W; altitude 300 m]; holotype: MZUSP 40129GoogleMaps  ).

Material examined

Brazil: Estado de Pernambuco, rio São Francisco basin: MZUSP 40129, holotype, male, 41.1 mm SL; MZUSP 40130, 3 paratypes; MNRJ 11556, 2 paratypes; UFRJ 146, 2; UFRJ 281, 1 (c&s); UFRJ 4565, 2 (c&s); vicinities of Lagoa Grande, Santa Maria da Boa Vista ; G. C. Brasil, 16 May 1989.  UFRJ 5186, 3; Irecê; D. Nielsen & A. Carletto, May 2000. 


Similar to S. flagellatus  ZBK  and S. janaubensis  , and distinguished from remaining species of the S. antenori  group by having iridescent dots on anal fin restricted to posterior portion of fin in males (vs. on the whole fin), anterior portion of anal fin pink and posterior portion yellow in males (vs. dark bluish gray in S. antenori  and whole fin yellow in S. ghisolfii  ZBK  , S. mediopapillatus  , S. macaubensis  , and S. igneus  ZBK  ), and a distal gray stripe on anal fin in males (vs. black distal stripe). Differs from S. flagellatus  ZBK  and S. janaubensis  by possessing minute contact organs on pectoral fins in males (vs. pronounced), dorsal profile of head nearly straight (vs. concave), and anterobasal portion of dorsal fin with small light spots, sometimes slightly elongated (vs. elongated brilliant white to light blue spots, forming short bars).


Morphometric data appear in Table 6. Largest specimen examined 41.1 mm SL. Dorsal profile nearly straight 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, nearly 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 both dorsal and anal fins with filamentous rays in males, tips reaching beyond distal border of caudal fin. Caudal fin subtruncate in males, round in females. Pectoral fins elliptical. Posterior margin of pectoral fins reaching vertical between base of 5th and 7th anal-fin ray in males, and through base of 1st or 2nd anal-fin ray in females. Tip of pelvic fins reaching base of 3rd or 4th anal-fin ray in males and between urogenital papilla and base of 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 between base of 3rd and 5th anal-fins ray in females; dorsal-fin origin between neural spines of vertebrae 7 and 8 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 8 and 10 in females. Dorsal-fin rays 22-24 in males, 16-18 in females; anal-fin rays 23-24 in males, 19-21 in females; caudal-fin rays 24-26; pectoral-fin rays 13-14; pelvic-fin rays 6.

Frontal squamation E-patterned; E-scales overlapping medially; no scales anterior to G-scale; one supraorbital scales. Longitudinal series of scales 29; transverse series of scales 12-13; scale rows around caudal peduncle 16. Minute contact organ on each scale of anteroventral portion of lateral surface of body in males, usually inconspicuous. Small papillate contact organs on inner surface of three dorsalmost rays of pectoral fins in males.

Cephalic neuromasts: supraorbital 15-16, parietal 2, anterior rostral 1, posterior rostral 1, infraorbital 2 + 18-20, preorbital 2, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 14-17, mandibular 13-14, lateral mandibular 4-5, paramandibular 1. One neuromast on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, width about 70% of length; basihyal cartilage about 20% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 7-8. Gill-rakers on first branchial arch 4 + 11. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 28-30.


Males. Sides of body light bluish to purplish gray, with 8-10 pale gray bars, ventral portion of median stripes abruptly widening towards its ventral tip. Opercular region pale greenish blue. Iris light yellow, with dark purplish gray bar. Dorsal fin dark purplish pink on anterior three fourths to dark yellow on posterior portion, with small white spots; spots on anterobasal region of fin slightly elongated; dorsal-fin filaments dark purple. Anal fin dark purplish pink on anterior two thirds to dark yellow on posterior portion, with small white dots restricted to the yellow zone; dark gray distal stripe; anal-fin filaments black. Caudal fin dark yellow, with bluish white dots, and metallic light blue line on posterior edge of fin. Pectoral fins hyaline. Pelvic fins pink, with gray tip.

Females. Side of body light gray, with 10-15 gray bars; venter pale golden; 1-2 rounded faint gray blotches on anterocentral portion of flank; 1-3 irregularly arranged rounded faint gray blotches on caudal peduncle; blotches sometimes inconspicuous. Opercular region pale greenish golden. Iris light yellow, with gray bar. 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.


Middle rio São Francisco basin, Estado de Pernambuco, northeastern Brazil (Fig. 1).


Temporary pools in the Caatinga.