Simpsonichthys macaubensis

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 : 100-101

Simpsonichthys macaubensis Costa & Suzart, 2006

(Figs. 63)

Simpsonichthys ghisolfii non S. ghisolfii Costa, Cyrino & Nielsen; Costa, 2006a: 22 (misidentification).

Simpsonichthys macaubensis Costa & Suzart in Costa, 2006b: 34 ( type locality: temporary pool near Macaubas , rio Paramirim drainage, rio Sao Francisco basin , about 13°00’S 42°30’W, Estado da Bahia, Brazil; holotype: UFRJ 6385 ).

Material examined

Brazil: Estado da Bahia, rio São Francisco basin: UFRJ 6385 , holotype, male, 38.6 mm SL; UFRJ 6105 , 1 paratype; UFRJ 6106 , 12 paratypes (c&s); temporary pool near Macaubas , rio Paramirim drainage , R. Suzart, Feb. 2003.

Diagnosis

Distinguished from all other species of the S. antenori group by the following combination of characters: contact organs on ventral portion of flanks in males (vs. contact organs absent in S. mediopapillatus , S. flavicaudatus , S. flagellatus , and S. janaubensis ); dorsal and anal-fin filaments slightly long, posteriorly reaching central portion of caudal fin in males (vs. short, reaching caudal-fin base in S. antenori , or long, surpassing posterior margin of caudal fin in S. igneus , S. flavicaudatus , S. flagellatus , and S. janaubensis ); urogenital papilla short in males (vs. long in S. ghisolfii and S. mediopapillatus ); caudal fin yellow in males (vs. bluish gray in S. antenori ); anal fin yellow, with distal black stripe, and iridescent dots over entire anal fin in males (vs. anal fin pink anteriorly and yellow posteriorly, with gray distal stripe and iridescent dots restricted to posterior portion of fin in S. flavicaudatus , S. flagellatus , and S. janaubensis ); no red pigmentation on anal fin in males (vs. subdistal reddish orange in S. antenori and S. igneus ); caudal peduncle bars slightly curved in males (vs. zigzag shaped in S. ghisolfii and S. mediopapillatus ).

Description

Morphometric data appear in Table 6. Largest specimen examined 38.7 mm SL. Dorsal profile approximately straight 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 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 fin pointed in males, slightly pointed in females; tip of anal fin pointed in males, rounded in females. Tip of both dorsal and anal fins with short filamentous rays in males, in both cases reaching vertical through center of caudal fin. Caudal fin subtruncate in males, rounded in females. Pectoral fins elliptical. Posterior margin of pectoral fins reaching vertical between base of 6th and 9th anal-fin rays in males, and between base of 1st and 3rd anal-fin rays in females. Tip of each pelvic fin reaching base of 3rd anal-fin ray in males and between base of 1st and 3rd anal-fin rays in females. Pelvic-fin bases medially united. Dorsal-fin origin in vertical through base of 2nd or 3rd anal-fin ray in males, and between base of 5th and 6th anal-fins ray in females; dorsal-fin origin between neural spines of vertebrae 7 and 9 in males, and neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 6 and 8 in males, and pleural ribs of vertebrae 8 and 9 in females. Dorsal-fin rays 21-23 in males, 14-16 in females; anal-fin rays 21-23 in males, 19 in females; caudal-fin rays 21-22; pectoral-fin rays 12-13; pelvic-fin rays 6.

Frontal squamation E-patterned; E-scales overlapping medially; no scales anterior to H-scale; two or three supraorbital scales. Longitudinal series of scales 27-29; transverse series of scales 12-13; scale rows around caudal peduncle 16. Contact organ on posterior margin of each scale of ventral portion of flank in males. Small papillate contact organs on inner surface of dorsal-most ray of pectoral fin in males.

Cephalic neuromasts: supraorbital 14, parietal 2, anterior rostral 1, posterior rostral 1, infraorbital 2 + 18, preorbital3, otic 2, post-otic 3, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 15, mandibular13, lateral mandibular 3, paramandibular 1. One neuromast on each scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal subtriangular, greatest width about 75-80% of length; basihyal cartilage about 30-35% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 7-9. Gill-rakers on first branchial arch 4 + 11. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 27-29.

Coloration

Males. Sides of body light gray, with 13-15 approximately straight faint gray stripes, more conspicuous on caudal peduncle, and bluish white dots. Dorsum pale brown. Venter light gray. Opercular region pale green. Iris light yellow, with dark purplish gray bar through center of eye. Unpaired fins yellow, with white to bluish white dots; dorsal-fin filaments dark yellow; anal-fin filaments black; black distal stripe on anal fin. Pectoral fins hyaline. Pelvic fins yellow.

Females. Sides of body light gray, with 14-18 narrow dark gray bars; 2-3 black small spots on anterocentral portion of flanks; 1-7 irregularly arranged rounded black blotches on caudal peduncle. Dorsum dark gray. Venter light gray. Opercular region pale greenish golden. Iris light yellow, with gray bar through center of eye. Unpaired fins hyaline, with faint, longitudinally elongated gray spots. Paired fins hyaline.

Distribution

Rio Paramirim drainage, rio São Francisco basin, Estado da Bahia, Brazil (Fig. 1).

Habitat

Temporary pools in the Caatinga.