Austrolebias nigrofasciatus M Costa & Cheffe 2001, sp. nov.
Creators: name: M Costa, Wilson J. E.
name: Cheffe, Morevy M.
Publisher: name: Zenodo
Year: 2001
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Cyprinodontiformes
Rivulidae
Austrolebias
Austrolebias nigrofasciatus

description: 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).
description: Published as part of 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), pp. 179-200 in Comun. Mus. Ciênc. Tecnol. PUCRS, Sér. Zool. 14 (2) on pages 187-190, DOI: 10.5281/zenodo.10138519