Simpsonichthys janaubensis, Wilson J. E. M. Costa, 2006

Wilson J. E. M. Costa, 2006, Three new species of seasonal killifishes of the Simpsonichthys antenori species group (Teleostei: Cyprinodontiformes: Rivulidae) from the rio São Francisco basin, Brazil., Zootaxa 1306, pp. 25-39 : 27-30

Simpsonichthys janaubensis , new species

(Figs. 1-2)

Simpsonichthys flagellatus non S. flagellatus Costa ; Costa, 2003: 46 (misidentification).

Holotype. UFRJ 5409 , male, 39.4 mm SL; Brazil: Estado de Minas Gerais: rio Gorutuba floodplains, rio Verde Grande drainage, middle rio Sao Francisco basin, Janauba , 15°48’5.9”S 43°19’13.5”W, altitude 556m ; W. J. E. M. Costa, C. P. Bove & B. B. Costa, 21 Jan. 2002.

Paratypes. UFRJ 5409 , 2 females, 27.4-31.6 mm SL; UFRJ 5410 , 3 males, 32.6-35.9 mm SL, 3 females, 28.6-29.7 mm SL (c&s); UFRJ 5411 , 7 males, 25.8-43.1 mm SL, 17 females, 24.2-31.3 mm SL; collected with holotype. UFRJ 6076 , 6 males, 24.3-30.0 mm SL, 4 females, 20.7-24.7 mm SL; MCP 40138 , 3 males, 26.0-26.7 mm SL, 2 females, 21.1-21.8 mm SL; same locality and collectors, 28 Jan. 2006.

Diagnosis. Similar to S. flavicaudatus and S. flagellatus in having a unique color pattern of the anal fin in males, consisting of anterior portion of fin pink and posterior portion yellow, with iridescent dots restricted to posterior portion of fin. Differs from S. flavicaudatus and S. flagellatus in possessing elongated light blue spots along entire dorsal-fin base (vs. elongated spots restricted to the anterobasal portion of dorsal fin), a shorter anal-fin base in males (34.4-38.4 % SL, vs. 39.0-45.2 % SL), and a more slender trunk and caudal peduncle (body depth 33.9-38.4 % SL in males and 30.7-36.8 % SL in females vs. 37.8-41.9 % SL in males and 37.0-42.7 % SL in females; caudal peduncle depth 12.6-14.3 % SL in males and 11.7-13.6 % SL in females vs. 14.4-16.6 % SL in males and 13.4-16.4 % SL in females).

Description. Morphometric data appear in Table 1. Males larger than females, the largest male examined 43.1 mm SL, largest female examined 31.6 mm SL. Dorsal profile gently concave on head, convex from nape to end of dorsal-fin base, about straight to slightly concave on caudal peduncle. Ventral profile convex from lower jaw to end of analfin base, approximately straight to slightly concave on caudal peduncle. Body moderately deep, compressed, greatest body depth at level of pelvic-fin base. Snout slightly pointed. Urogenital papilla cylindrical and short in males.

Tip of dorsal fin pointed in males, slightly pointed in females; tip of anal fin pointed in males, rounded in females. Tips of both dorsal and anal fins with long filamentous rays in males, the tips reaching posterior portion 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 rays in males, and between urogenital papilla and base of 2nd anal-fin ray in females. Tips of pelvic fins reaching between base of 1st and 4th anal-fin ray in males and base of 1st or 2nd anal-fin ray in females. Pelvic-fin bases medially united. Dorsal-fin origin slightly anterior to anal-fin origin in males, anal-fin origin in vertical between base of 2nd and 4th dorsal-fin rays; dorsal-fin origin slightly anterior or slightly posterior to anal-fin origin in females, in vertical between base of 1st and 3rd anal-fin rays. Dorsal-fin origin between neural spines of vertebrae 6 and 8 in males, and neural spines of vertebrae 10 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 7 and 8 in males, and pleural ribs of vertebrae 8 and 9 in females. Dorsal-fin rays 22-26 in males, 15-19 in females; anal-fin rays 22-25 in males, 20-22 in females; caudal-fin rays 23-25; pectoral-fin rays 12-13; pelvic-fin rays 6.

Scales large, cycloid. Body and head entirely scaled, except on ventral surface of head. Trunk squamation slightly extending on middle of anal-fin base. Scales extending onto anterior fifth of caudal fin. Frontal squamation E-patterned; E-scales overlapping medially; no scales anterior to H-scale; two supraorbital scales. Longitudinal series of scales 29-31; transverse series of scales 13-14; scale rows around caudal peduncle 16. No contact organs on scales. Prominent papillate contact organs on inner surface of three dorsalmost rays of pectoral fin in males.

Cephalic neuromasts: supraorbital 14-18, parietal 2, anterior rostral 1, posterior rostral 1, infraorbital 2 + 21-23, preorbital 3, otic 2, post-otic 4, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 14-19, mandibular 14-18, lateral mandibular 4-6, paramandibular 1. One neuromast on each scale of lateral line. Two neuromasts on caudalfin base.

Basihyal subtriangular, longest width about 70 % of length; basihyal cartilage about 25 % of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 8-10. Gill-rakers on first branchial arch 4 + 11. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal long. Total vertebrae 30-31.

Coloration. Males: Sides of body pale golden, with 10-13 dark gray, approximately vertical and straight bars, ventral portion of bars often wider and slightly directed anteriorly. Dorsum pale brown. Venter gray. Opercular region pale greenish golden. Iris light yellow, with dark purplish gray bar through center of eye. Dorsal fin purplish pink on anterior three fourths, yellow on posterior fourth; small round light blue spots over fin, spots on basal region vertically elongated, alternating with dark gray areas on anterior portion of basal portion of fin; dorsal-fin filaments dark brownish purple. Anal fin purplish pink on anterior half to two-thirds, yellow with light blue dots on posterior portion, some dots sometimes coalescing to form elongated oblique spots; pale gray distal stripe; anal-fin filaments black. Caudal fin yellow, with light blue small spots and light blue line on posterior edge of fin. Pectoral fins hyaline. Pelvic fins pink.

Females: Sides of body light gray, with 11-14 dark gray bars, 1-2 rounded black blotches on anterocentral portion of flank, and 1-3 rounded black blotches on caudal peduncle, these sometimes absent. Dorsum pale brown. Venter pale golden. Opercular region pale greenish golden. Iris light yellow, with gray vertical 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 and habitat. Known only from a temporary pool in the floodplains of the middle rio Gorutuba, rio Verde Grande drainage, rio São Francisco basin, Estado de Minas Gerais, Brazil (Fig. 3).

In the first collection (21 January 2002), the pool surface was about 200 m × 30 m, and the depth about 0.50-1.00 m. The pool was situated in a typical semi-arid Caatinga area, containing many aquatic plants. The water was slightly turbid, with a pH of 7.0. However, due to urban expansion of the city of Janaúba, we found the original pool partly destroyed on the second trip (18 January 2005), reduced to small (about 10 m x 10 m) and shallow (about 0.50 m deep) isolated pools with all aquatic and marginal vegetation removed.

Etymology. The name janaubensis is an allusion to the occurrence of the new species in Janaûba, Minas Gerais, Brazil.