Austrolebias nigrofasciatus, M Costa & Cheffe, 2001

M Costa, Wilson J. E. & Cheffe, Morevy M., 2001, THREE NEW ANNUAL FISHES OF THE GENUS Austrolebias FROM THE LAGUNA DOS PATOS SYSTEM, SOUTHERN BRAZIL, AND A REDESCRIPTION OF A. adloffi (AHL) (CYPRINODONTIFORMES: RIVULIDAE), Comun. Mus. Ciênc. Tecnol. PUCRS, Sér. Zool. 14 (2), pp. 179-200 : 187-190

Austrolebias nigrofasciatus , sp. nov.

(Figs. 6-7)

Holotype. MCP 21172 , male, 42.7 mm SL; Brazil. Rio Grande do Sul. Temporary pool in Pontal da Barra , praia de Laranjal , Pelotas; M. Cheffe, G. Maurício and L. Matheus, 15 Oct. 1995 . Paratypes. Brazil. Rio Grande do Sul. UFRJ 4016 , l male, 38.8 mm SL, and 8 females, 34.2 -40.1 mm SL; collected witlı holotype . - MUCP 2561 , 33 males, 17.2-32.1 mm SL, and 24 females, 18.8-29.4 mm SL; same locality, M. Cheffe and G. Maurício, l Oct. 2000 . — MCP 21173 , 3 males, 25.2-29.0 mm SL, and 3 females, 26.0- 34.4 mm SL ; UFRJ 5343 ., 8 males, 25.7 -31.4 mm SL, and 7 females, 24.8-30.2 mm SL ; UFRJ 4219 , 12 males, 25.7 -33.4 mm SL, and 7 females, 20.4 -29.6 mm SL; same locality; M. Cheffe and G. Maurício, 16 Aug. 1993 . — UFRJ 4015 , 9 males, 26.7-31.1 mm SL, and 17 females, 23.1 -31.9 mm SL; M. Cheffe, G. Maurício and L. Matheus, 7 Nov. 1993 . - UFRJ 4218 , 4 males, 30.0 -35.1 mm SL, and 7 females, 28.1 -35.8 mm SL; same locality; M. Cheffe, G. Mauricio and L. Matheus, 22 Aug. 1991 .. - UFRJ 4259 , 5 males, 30.4-34.5 mm SL, and 8 females, 28.7-36.7 mm SL; same locality; M. Cheffe and G. Mauricio, 24 Sept. 1993 . - UFRJ 4014 , 3 males, 27.3 -34.5 mm SL, and 4 females, 24.2 -25.8 mm SL (all c& s), same locality; G. Mauricio, 04 Dec. 1996 .

Additional material (non type specimens). Brazil. Rio Grande do Sul. Laguna dos Patos system. UFRJ 4220 , 37 ex., same locality as holotype; M. Cheffe, G. Mauricio & L. Matheus, 04 Jul. 1993 . - UFRJ 4178 , 13 exc, temporary pool close to arroio Grande , 26 km E of the road BR- 116; W. J. E. M. Costa, M. I. Landim and C. Moreira, 19 Jul. 1997 . - UFRJ 4206 , 102 ex.; temporary pool close to arroio Grande , 10 km E of the road BR-l 16; W. J. E. M. Costa, M. I. Landim and C. Moreira, 19 Jul. 1997 . - UFRJ 4992 , 10 ex.; ditch at road side, between Arroio Grande and lagoa Mirim ; W. J. E. M. Costa and A. C. Bacellar, 08 Sept. 1999 . - UFRJ 5010 , 11 ex ; UFRJ 501 l , 3 ex. (c&s); Arroio Grande , road BR- 116; W. J. E. M. Costa and A. C. Bacellar, 08 Sept. 1999 . - UFRJ 5007 , 19 ex., UFRJ 5060 , 6 ex. (c&s); temporary pool, road BR- 116, 43 km NE of Arroio Grande; W. J. E. M. Costa and A. C. Bacellar, 08 Sept. 1999 . - MUCP 5007 , 19 ex., temporary swamp of passo do Salso , Arroio Grande; M. Cheffe and G. Mauricio, 29 Nov. 2000 . - UFRJ 4177 , 69 ex., temporary swamp 12 km NE of Jaguarão, road BR- 1 16 ; W. J. E. M. Costa, M. I. Landim and C. Moreira, 19 Jul. 1997 .

Diagnosis. Similar to A. adloffi , A. charrua , A. minuano , and distinguished from all other species of the genus by possessing two apomorphic color patterns, consisting of body side of male bright gray with dark gray to black stripes (vs. light gray or no stripes) and a vertically paired black blotch on the end of the caudal peduncle of juvenile and female (vs. small spots irregularly arranged, or a single round dorsally positioned spot, or no spots on caudal peduncle). It differs from A. adloffi , A. charrua , A. minuano by reduced number of anal-fm rays (21 -26 in male, modal number 23, vs. 26 -30 in male of A. adloffi , modal number 26, and 23 -29 in male of A. charrua and A. minuano , modal number 26 in both; and, 18-22 in female, modal number 21, vs. 23 -26 in female of A. adloffi , modal number 24, and 20 -27 in A. charrua and A. minuano , modal number 22 in both; see Table 5), light blue stripes parallel to rays on the basal half of unpaired fins of male (vs. rounded to elongate white spots in the other species), and a black blotch anteriorly bordered by a narrow blue line, both on the posterior portion of dorsal and anal fin of male (vs. no distinctive blotch). It is further distinguished from A. adloffi by female having dorsal-fin origin anterior to anal-fin origin (vs. posterior to anal-fin origin), from A. charrua by having fewer scales on the longitudinal series (26-28 vs. 28-30) and fewer supraorbital neuromasts (16-19 vs. 19-24), and from A. minuano by having fewer second pharyngobranchial teeth (2-5 vs. 6-7).

Description. Morphometric data are given in Table 3. Male larger than female, reaching at least 42.7 mm SL. Dorsal profile convex between snout and dorsal-fin base end, approximately straight on caudal peduncle. Protuberance on interorbital region of adult specimens of both sexes, more prominent in male. Ventral profile convex from lower jaw to end of anal-fin base, nearly straight on caudal peduncle. Body deep, compressed, body width approximately 2.2 in body depth in larger males. Longest body depth at vertical through anal-fin origin. Snout blunt. Jaws short.

Tip of dorsal and anal fins rounded. Border of membrane of anterior portion of dorsal fin of male not distinctively indented. Anteromedian rays of anal fin of female lengthened, resulting in approximately triangular fin shape. Urogenital papilla of male not attached to anal fin. Caudal fin rounded. Pectoral fin elliptical. Posterior margin of pectoral fin reaching vertical through base of fifth anal-fin ray in male, and urogenital papilla in female. Tip of pelvic fin reaching between base of third and fourth anal-fin ray in male and between base of first and third anal-fin ray in female. Pelvic fins medially united along proximal half. Dorsal-fin origin in a vertical through base of first or second anal-fin ray in male, and slightly anterior to anal-fin origin, in vertical through urogenital papilla or anal-fin origin in female. Anal-fin origin of female in vertical between base of first and third dorsal-fin ray. Dorsal-fin rays: 19 -23 in male, 16- 20 in female. Anal-fin rays: 21 -26 in male, 18-22 in female. Caudal-fin rays: 20 -22. Pectoral-fin rays: 10-ll. Pelvic-fin rays: 5.

Scales large, cycloid. Body and head entirely scaled, except on ventral surface of head. Frontal squamation F-patterned. No transverse row of scales on anal-fin base. Pectoral-fin base naked. Longitudinal series of scales: 26-28. Transverse series of scales: 11 - 12. Scale rows around caudal peduncle: 16. Three to seven minute ctenii-like contact organs on each scale of lateral surface of ventral portion of body and opercular region of male. Often small papillate contact organs on distal portion of the first five anal-fin rays of male. No contact organs on dorsal fin and outer surface of pectoral and pelvic fins. Small papillate contact organs on inner surface of three dorsalmost rays of pectoral-fin of male. Supraorbital neuromasts: 16- 19.

Basihyal slightly widened, its longest width about 65 -80% of its longitudinal length; basihyal cartilage long, about 55 % of total longitudinal length of basihyal, and with lateral projections. Six branchiostegal rays. Four to five teeth on second pharyngobranchial. Gill-rakers on first branchial arch: 4 + 10. Lateral process of sphenotic narrow, without anterior expansion. Dermosphenotic absent. Ventral process of postteinporal long. Total vertebrae: 27-30.

Coloration. Male. Side of body bright gray with iridescent light blue spots, with 6- 12 dark vertical stripes; anterior stripes narrower and black, gradually changing to wider and dark purplish brown posteriorly; posteriormost stripe usually darker than penultimate three or four stripes, corresponding to blotch present in juvenile and adult female; dark stripes usually narrower than light interspace, rarely as wide as light interspace or slightly wider. Opercular and preopereular regions blue. Black vertical suborbital stripe, and black oblique supraorbital stripe. Iris yellow; dark gray vertical bar crossing eye. Unpaired fins dark gray with short light blue stripes on basal portion of fins, parallel to fin rays; posterior portion of dorsal and anal fins with distinctive black blotch, anteriorly bordered by light blue line; distal half of dorsal fin usually with pink iridescence, and distal half of caudal and anal fin with blue iridescence. Pelvic fin bluish dark gray. Pectoral fin hyaline, with bluish black ventral edge.

Female. Side of body pale brownish gray, with light brown spots, often vertically elongated, sometimes forming vertical stripes. No spots on anterocentral portion of body side. Venter pale golden. Usually two black spots vertically arranged on posterior portion of caudal peduncle, sometimes coalesced forming single 8-shaped blotch, rarely one spot or both absent. Opercular and preopereular region pale blue to pale yellowish green. Faint vertical, gray suborbital stripe. Iris light yellow; gray vertical bar crossing eye. Unpaired fins hyaline with small dark gray spots on distal portion and dark gray stripes parallel to rays on basal portion. Paired fins hyaline, sometimes gray stripe along ventral border of pectoral fin.

Etymology. From the Latin nigrum: (black) and fasciatus (with stripes), in reference to the color pattern of male of the new species. An adjective.

Distribution. Known from some localities along the inner coastal plains to lagoa Mirim, canal de São Gonçalo and tributaries, laguna dos Patos system, between Pelotas and Jaguarão, Rio Grande do Sul, southern Brazil (Fig. l).