Austrolebias juanlangi, Wilson J. E. M. Costa, 2006

Wilson J. E. M. Costa, 2006, The South American annual killifish genus Austrolebias (Teleostei: Cyprinodontiformes: Rivulidae): phylogenetic relationships, descriptive morphology and taxonomic revision., Zootaxa 1213, pp. 1-162 : 86-90

Austrolebias juanlangi Costa, Cheffe, Salvia & Litz, new species

(Fig. 34)

Austrolebias affinis non A. affinis Amato; Costa, 2002b: 105 (misidentification of specimens from the upper rio Negro basin).

Material examined

Holotype. UFRJ 6199 , male, 33.7 mm SL; Brazil: Rio Grande do Sul: Jaguarao : temporary swamp near banhado do Minuano, road BR-153, rio Jaguarao Chico drainage, rio Jaguarao basin, a tributary of lagoa Mirim, laguna dos Patos system , 31°40’48”S 54°8’45”W; M. M. Cheffe, 2 Dec. 2000.

Paratypes. Brazil: Rio Grande do Sul: UFRJ 6200 , 3 males, 29.2-30.2 mm SL, 3 females, 24.0-28.4 mm SL; CIMC 3593 , 3 males, 26.8-29.8 mm SL, 3 females, 23.3-25.5 mm SL; UFRJ 6201 , 2 males, 33.1-33.4 mm SL, 1 female, 25.6 mm SL (c&s); all collected with the holotype . CIMC 8226 , 16 males, 18.4-28.8 mm SL, 17 females, 19.4-24.7 mm SL; temporary swamp near arroio Telho, Jaguarao ; L. E. K. Lanés, M. V. Volcan, B. Klotzel & G. M. Wallwitz, 5 Sep. 2004. UFRJ 4985 , 103 males, 19.3-30.7 mm SL, 162 females, 17.8-26.0 mm SL; UFRJ 5018 , 5 males, 27.4-27.9 mm SL, 2 females, 24.8-26.3 mm SL (c&s); MCP 28041 , 5 males, 24.7-25.7 mm SL, 5 females, 18.8-23.2 mm SL; temporary pool 42 km S of Bage , road BR-153, area between upper rio Negro basin and upper rio Jaguarao basin ; W. J. E. M. Costa & A. C. Bacellar, 5 Sep. 1999. UFRJ 4984 , 7 males, 24.0-26.9 mm SL, 13 females, 19.8-23.9 mm SL; temporary pool 27 km S of Bage , road BR-153, upper rio Negro basin ; W. J. E. M. Costa & A. C. Bacellar, 5 Sep. 1999. UFRJ 4983 , 15 males, 20.9-25.9 mm SL, 5 females, 16.6-21.2 mm SL; temporary pool 9.5 km S of Bage , road BR-153, upper rio Negro basin ; W. J. E. M. Costa & A. C. Bacellar, 5 Sep. 1999. UFRJ 5041 , 5 males, 24.2-26.8 mm SL, 6 females, 19.1-24.1 mm SL; temporary pool 19 km S of Bage , road BR-153 ; W. J. E. M. Costa & A. C. Bacellar, 5 Sep. 1999. Uruguay: Cerro Largo: MUNHINA 3214 , 15 males, 21.1-30.7 mm SL, 19 females, 17.8-27.1 mm SL; temporary pool near rio Negro, Paso de Mazangano, Ruta 44 , 32°06.68’S 54°39.96’W; P. Laurino, T. Litz, E. Perujo, H. Salvia & J. Salvia, 29 Aug. 2004. ZSM 33651 , 13 males, 22.5-34.4 mm SL, 18 females, 23.8-28.5 mm SL; Ruta 44, km 44.4, rio Negro basin , 32°10.38’S 54°32.07’W; P. Laurino, T. Litz, E. Perujo, H. Salvia & J. Salvia, 29 Aug. 2004. UFRJ 6202 , 1 male, 37.9 mm SL, 1 female, 33.9 mm SL; UFRJ 6203 , 3 males, 29.8-37.9 mm SL, 4 females, 24.6-32.9 mm SL; MUNHINA 3206 , 5 males, 28.2-40.9 mm SL, 7 females, 26.0-40.3 mm SL; Ruta 26, km 372 , 32°17.29’S 54°48.27’W; P. Laurino, T. Litz, E. Perujo, I. Perujo & H. Salvia, 17 Aug. 2002. MUNHINA 3213 , 26 males, 15.9-30.7 mm SL, 62 females, 15.9-30.7 mm SL; temporary pool at Ruta 26, km 406, area between upper rio Negro and rio Tacuari basins , 32°22.10’S 54°27.76’W; P. Laurino, T. Litz, E. Perujo, H. Salvia & J. Salvia, 29 Aug. 2004. ZSM 33652 , 11 males, 18.0-28.7 mm SL, 18 females, 17.8-24.6 mm SL; temporary pool at Ruta 26, km 405, area between upper rio Negro and rio Tacuari basins , 32°21.91’S 54°28.49’W; P. Laurino, T. Litz, E. Perujo, H. Salvia & J. Salvia, 29 Aug. 2004. MUNHINA 3212 , 16 males, 17.7-36.3 mm SL, 22 females, 19.2-30.4 mm SL; UFRJ 6204 , 3 males, 26.6-30.2 mm SL, 2 females, 22.2-24.4 mm SL; UFRJ 6205 , 3 males, 25.3-32.2 mm SL, 2 females, 23.4-24.3 mm SL; Banados Conventos, rio Tacuari basin , 32°21.20’S 54°14.22’W; P. Laurino, T. Litz, E. Perujo, I. Perujo & H. Salvia, 18 Aug. 2002. ZSM 33653 , 3 males, 22.8-30.4 mm SL, 5 females, 20.3-24.6 mm SL; Melo, rio Tacuari basin , 32°22.47’S 54°12.32’W; P. Laurino, T. Litz, E. Perujo, I. Perujo & H. Salvia, 18 Aug. 2002. MUNHINA 3207 , 14 males, 22.3-30.6 mm SL, 22 females, 19.3-27.0 mm SL; Parque Rivera, Melo, rio Tacuari basin , 32°22.46’S 54°11.32’W; P. Laurino, T. Litz, E. Perujo, I. Perujo & H. Salvia, 18 Aug. 2002. Treinta y Tres: MUNHINA 3215 , 9 males, 17.0-36.7 mm SL, 9 females, 17.2-31.3 mm SL; UFRJ 6206 , 2 males, 30.9-35.6 mm SL, 2 females, 25.2-31.4 mm SL; UFRJ 6207 , 2 males, 27.9-29.1 mm SL, 1 female, 26.9 mm SL (c&s); temporary pool near rio Tacuari , Paso del Dragon , 32°45.95’S 53°43.19’W; P. Laurino, T. Litz, H. Salvia & J. Salvia, 30 Aug. 2004.

Additional material (non types). Uruguay: Cerro Largo: CTL 1490 , 20; Ruta 26, km 372, rio Negro basin , 32°17.29’S 54°48.27’W; P. Laurino et al., 29 Aug. 2004. CTL 1566 , 47; idem ; P. Laurino et al., 29 Aug. 2004. Tacuarembó: CTL 186 b, 42; Ruta 26, km 331, rio Negro basin , 32°05.56’S 55°8.48’W; P. Laurino et al., 17 Aug. 2002.

Diagnosis

Similar to A. affinis and A. duraznensis , and distinguished from all other species of the A. alexandri group by possessing the posterior margin of each pectoral fin in males reaching a vertical between urogenital papilla and base of second anal-fin ray (vs. between base of second and fifth anal-fin rays). Differs from A. affinis and A. duraznensis in having well-defined bright blue bars on flank in males (vs. blue bars substituted by vertical rows of blue dots, except sometimes narrow ill-defined bars on anteriormost portion of flanks), fewer neuromasts in preopercular (15-18, vs. 18-21 in A. duraznensis and 23-26 in A. affinis ) and mandibular series (9-10 vs. 11-13), and dorsal-fin origin on a vertical approximately through anal-fin origin in males (vs. conspicuously in front of anal-fin origin). Also differs from A. affinis by having fewer neuromasts in the infraorbital series (2 + 19-22, vs. 2 + 25-27) and light dots on unpaired fins in males restricted to the basal portion of fins (vs. over the entire fins).

Description

Morphometric data appear in Table 5. Males larger than female, largest male examined 33.7 mm SL, largest female 28.4 mm SL. Dorsal profile nearly straight to convex on head, convex from nape to end of dorsal-fin base, approximately straight on caudal peduncle; often adipose ridge on frontal region of head in males. Ventral profile convex from lower jaw to end of anal-fin base, nearly straight on caudal peduncle. Greatest body depth at level of pelvic-fin base. Body slender and compressed. Snout blunt and jaws short.

Tip of both dorsal and anal fins rounded. Anteromedian rays of anal fin of females not lengthened; distal portion of anal fin thickened in females. Caudal fin rounded. Pectoral fins rounded, posterior margin on vertical between pelvic-fin base and base of 2nd anal-fin ray in males, on vertical between pelvic-fin base and anus in females. Tip of each pelvic fin reaching between base of 2nd and 3rd anal-fin rays in males, between urogenital papilla and base of 1st anal-fin ray in females. Pelvic-fin bases united or in close proximity, medial membrane never coalesced. Urogenital papilla not attached to anal fin. Dorsal-fin origin approximately on vertical through anal-fin origin in males; anal-fin origin between bases of 1st and 3rd dorsal-fin rays in females; dorsal-fin origin between neural spines of 7th and 9th vertebrae in males, between neural spines of 10th and 12th vertebrae in females. Anal-fin origin between pleural ribs of 7th and 9th vertebrae in males, between pleural ribs of 10th and 12th vertebrae in females. Dorsal-fin rays 21-24 in males, 16-21 in females; anal-fin rays 21-25 in males, 17-21 in females; caudal-fin rays 25-28; pectoral-fin rays 10-11; pelvic-fin rays 5-6.

Scales large and cycloid. Trunk and head entirely scaled, except ventral surface of head. No scales on dorsal and anal-fin bases, and two rows of scales on caudal-fin base. Frontal squamation H-patterned; E-scales overlapping medially; scales arranged in transverse pattern. Longitudinal series of scales 25-28, scales regularly arranged; transverse series of scales 10-11; scale rows around caudal peduncle 16. One contact organ on each scale of ventral portion of flanks and opercle in males. Row of minute contact organs on two uppermost pectoral-fin rays in males, sometimes absent; no contact organs on unpaired fins.

Cephalic neuromasts: supraorbital 14-17, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital 2 + 19-22, preorbital 1-2, otic 2-3, post-otic 3-4, supratemporal 1, median opercular 1, ventral opercular 1-2, preopercular 15-18, mandibular 9-10, lateral mandibular 3-4.

Basihyal subtriangular, width about 60 % of length; basihyal cartilage moderate in length, about 45 % of total basihyal length, without lateral projections. Six branchiostegal rays. One to three teeth on second pharyngobranchial. Gill-rakers on first branchial arch 2-3 + 8-9. Dermosphenotic ossification absent. Ventral process of posttemporal vestigial. Total vertebrae 27-29.

Coloration

Males: sides of body dark bluish gray to dark brown, with 7-10 bright blue bars, anterior bars wider, bars on caudal peduncle often substituted by vertical rows bright blue dots in larger males. Urogenital papilla dark gray. Opercular and infraorbital regions bright blue; approximately rectangular, dark gray to black infraorbital bar; subtriangular dark gray to black supraorbital blotch, not reaching neuromast parietal series. Iris brown, with black bar through center of eye. Unpaired fins dark gray, with light blue to white dots over basal half of fins, sometimes restricted to single series on basal portion of fins; blue iridescence on distal portion of dorsal fin; intense bright blue iridescence on distal portion of anal fin, often forming distinctive stripe; bright blue iridescence on distal portion of caudal fin. Pelvic fins bluish gray with light blue basal spot. Pectoral fins dark bluish gray, with bright blue iridescence.

Females: sides of body light yellowish brown, with dark gray spots, usually as large as eye, sometimes smaller, usually vertically elongated, sometimes forming short bars above anal fin; sometimes 1 or 2 black spots on anterocentral portion of flanks and 1 or 2 on caudal peduncle; venter pale golden. Opercular region pale greenish golden. Iris light yellow with gray bar through center of eye. Infraorbital and supraorbital bars dark gray. Unpaired fins hyaline, with dark gray spots, darker and elongated on basal portion; paired fins hyaline.

Distribution

Jaguarào and Tacuarí drainages of the lagoa Mirim basin, and upper río Negro basin, southern Brazil and northestern Uruguay (Fig. 20).

Etymology

Named in honor of the late Juan Jorge Reichert Lang, in appreciation for his dedication in collecting and illustrating Uruguayan species of Austrolebias .

Remarks

Different Uruguayan populations of this species have appeared in the aquarium literature (e. g., Reichert et al., 1997) under a series of code names (e. g., CXCL007 and CXCL009). The present examination of preserved material revealed that all populations are conspecific.