Austrolebias vazferreirai

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 : 34-37

Austrolebias vazferreirai (Berkenkamp, Etzel, Reichert & Salvia)

(Fig. 13)

Cynolebias vazferreirai Berkenkamp, Etzel, Reichert & Salvia, 1994: 11 ( type locality: km 44 of the road Ruta 44, from Melo to Riveira [correctly Rivera] , Departamento Cerro-Largo, western [northeastern] Uruguay, [ río Negro drainage, río Uruguay basin], 32°15’S 54°30’W [correctly 32°10.38’S 54°32.07’W]; holotype: SMF 18453 ).

Cynolebias nioni Berkenkamp, Reichert & Prieto, 1997: 31 ( type locality: temporary swamp in canada Los Cinco Sauces, rio Negro system [ rio Uruguay basin], km 331 of the road Ruta 26 , Departamento de Tacuarembó, northwestern [correctly northeastern] Uruguay, 32°10”S 55°15”W [correctly 32°5.45’S 55°8.90’W]; holotype: SMF 18457 ).

Material examined

Uruguay: Cerro Largo: CTL 1574 , 1; Ruta 44, km 44.4, rio Negro drainage, rio Uruguay basin ; P. Laurino et al., 29 Aug. 2004. UFRJ 6151 , 4; UFRJ 6152 , 3 (c&s); CTL 1490a , 6; Ruta 26, km 372, rio Negro drainage, rio Uruguay basin , 32°17.29S 54°48.27W; P. Laurino et al., 29 Aug. 2004. UFRJ 61555 , 2; UFRJ 6156 , 2 (c&s); CTL 209 , 4; Melo, Parque Rivera, rio Tacuari drainage, laguna dos Patos system , 32°22.46S 54°11.32W; P. Laurino et al., 18 Aug. 2002. CTL 219 , 5; Melo, rio Tacuari drainage, laguna dos Patos system , 32°22.47S 54°12.32W; P. Laurino et al., 18 Aug. 2002. CTL 225 , 1; Banados Conventos , 32°21.20S 54°14.22W; P. Laurino et al., 18 Aug. 2002. CTL 1493 , 4; Paso de Mazangano, Ruta 44, rio Negro floodplains , 32º6.68’S 54°39.96W; P. Laurino et al., 29 Aug. 2004. Tacuarembó: UFRJ 6153 , 1; UFRJ 6154 , 2 (c&s); CTL 185 , 3; Ruta 26, km 331, rio Negro drainage, rio Uruguay basin , 32°5.45’S 55°8.90’W; P. Laurino et al., 17 Aug. 2002.

Diagnosis

Distinguished from all other species of the A. robustus group by the following combination of features: dorsal-fin origin on vertical between base of 1st or 3rd anal-fin ray in males, just anterior to anal-fin origin in females; scales in longitudinal series 30-35; vertebrae 29-32; flank gray, often with light vertical lines in males; spots on flank and no large spot at end of caudal peduncle in females.

Description

Morphometric data appear in Table 2. Males larger than females, the largest male examined 83.2 mm SL, largest female 64.7 mm SL. Dorsal profile of head slightly concave, convex from nape to end of dorsal-fin base, approximately straight on caudal peduncle; no distinctive adipose ridge on frontal region. 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 deep, slightly compressed. Snout blunt and jaws short.

Tip of both dorsal and anal fin rounded. Anteromedian rays of anal fin of females not lengthened; distal portion of anal fin thickened in females. Caudal fin rounded. Pectoral fins elliptical, posterior margin on vertical between base of 3rd and 6th anal-fin ray in males, between pelvic-fin base and urogenital papilla in females. Tip of each pelvic fin reaching between base of 2nd and 6th anal-fin rays in males, between urogenital papilla and base of 1st anal-fin ray in females. Pelvic-fin bases medially united, sometimes medial pelvic-fin margins about 20% united. Urogenital papilla not attached to anal fin. Dorsal-fin origin usually posterior to anal-fin origin in males, on vertical between base of 1st and 4th rays, sometimes slightly anterior to anal-fin origin; dorsal-fin origin anterior to anal-fin origin in females, anal-fin origin on vertical between base of 1st and 4th dorsal-fin rays; dorsal-fin origin between neural spines of 9th and 11th vertebrae in males, between neural spines of 10th and 12th vertebrae in females. Anal-fin origin between pleural ribs of 9th and 10th vertebrae in males, between pleural ribs of 11th and 12th vertebrae in females. Dorsal-fin rays 21-26 in males, 17-23 in females; anal-fin rays 23-28 in males, 21-25 in females; caudal-fin rays 26-30; pectoral-fin rays 12-13; pelvic-fin rays 4-5.

Scales large and cycloid. Trunk and head entirely scaled, except ventral surface of head. Often one or two rows of scales on anal-fin base; no scales on dorsal-fin base; three rows of scales on caudal-fin base. Frontal squamation F-patterned; E-scales not overlapping medially; scales arranged in transverse pattern. Longitudinal series of scales 30-35, scales regularly arranged; transverse series of scales 15-16; scale rows around caudal peduncle 22-26. One prominent contact organ on each scale of ventral portion of flank and opercle in males. Rows of prominent contact organs on anal-fin rays, and row of contact organs on four or five uppermost pectoral-fin rays in males. No contact organ on dorsal and caudal fins.

Cephalic neuromasts: supraorbital 19-27, parietal 1-5, anterior rostral 1, posterior rostral 1, infraorbital 2-3 + 23-31, preorbital 2-3, otic 4-6, post-otic 5-7, supratemporal 1, median opercular 1, ventral opercular 2-3, preopercular plus mandibular 38-50, lateral mandibular 5-8.

Basihyal subtriangular, width about 70-85 % of length; basihyal cartilage moderate, about 45-55 % of total basihyal length, with pronounced lateral projection. Six branchiostegal rays. Four to seven teeth on second pharyngobranchial. Gill-rakers on first branchial arch 3-4 + 11. Dermosphenotic ossification absent. Ventral process of posttemporal long. Total vertebrae 29-33.

Coloration

Males: sides of body dark brown to dark gray, sometimes bluish gray above anal fin, with faint light brown vertical lines, often with transverse branches forming approximately reticulate pattern, less conspicuous in older specimens; sometimes dark gray round spot on anterocentral portion of flank. Urogenital papilla dark gray. Opercular and infraorbital regions pale blue; approximately rectangular gray infraorbital bar, faint gray supraorbital bar. Iris dark orange with brown bar through center of eye. Unpaired fins dark gray with light gray dots on basal portion. Pelvic fins dark gray. Pectoral fins hyaline.

Females: sides of body light yellowish brown, with vertically elongated dark gray spots, sometimes forming short bars above anal fin; sometimes spots on anterocentral portion of flank and caudal peduncle darker. Opercular region pale blue. Iris dark orange, with brown bar through center of eye. Faint infraorbital and supraorbital gray bars. Unpaired fins hyaline, with small dark gray spots; paired fins hyaline.

Distribution

Río Negro drainage, río Uruguay basin, and río Tacuarí drainage, laguna dos Patos system, northeastern Uruguay (Fig. 8).

Remarks

Examination of topotypes of A. vazferreirai and A. nioni , both described from the upper río Negro basin, and material from adjacent localities in both the río Negro and río Tacuarí drainages, revealed that these species are not distinguishable by morphological characters. The maculate male pattern described for A. nioni is often found in A. vazferreirai and may be absent in larger topotypes of A. nioni . García et al. (2001) found karyotypic features distinguishing A. nioni and specimens from the río Tacuarí drainage, lagoa Mirim basin (then identified as A. vazferreirai ). Because of the high karyotypic variability recorded for species of Austrolebias (e. g., García et al., 1993, 1995) and the lack of karyotypic data for A. vazferreirai from the river basin from where it was described ( río Negro drainage, río Uruguay basin), the karyotypic data provided by García et al. (2001) are not considered to be sufficient for distinguishing A. nioni from A. vazferreirai .