Austrolebias luteoflammulatus

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 : 27-31

Austrolebias luteoflammulatus (Vaz-Ferreira, Sierra-de-Soriano & Scaglia-de-Paulete)

(Fig. 10)

Cynolebias luteoflammulatus Vaz-Ferreira, Sierra-de-Soriano & Scaglia-de-Paulete, 1964: 25 ( type locality: temporary swamp near arroyo Valizas , 34º26’S 53°26’W, Departamento de Rocha, Uruguay; holotype: ZVC-P 527 ).

Material examined

Uruguay: Rocha: UFRJ 6208 , 2 (c&s); CTL 1346 , 3; temporary swamp near arroyo Valizas, Ruta 10, km 267 , 34°21.55’S 53°50.64’W; P. Laurino et al., 27 Aug. 2004. MCP 15048 , 2; charco de Los Sauces ; R. Vaz-Ferreira, B. Sierra-de-Soriano & J. Soriano, 28 Jul. 1963. UFRJ 6209 , 4; CTL 1317 , 23; Ruta 9, km 205 , 34°30.16’S 54°20.06’W; P. Laurino et al., 27 Aug. 2004. UFRJ 6210 , 4; UFRJ 6211 , 4 (c&s); CTL 1324 , 10; La Pedrera, Ruta 10 , 34°36.77’S 54°09.52’W; P. Laurino et al., 27 Aug. 2004. UFRJ 6212 , 4; UFRJ 6213 , 4 (c&s); CTL 1456 , 22; Ruta 14, km 269, north to Lascano , 33°27.28’S 54°18.06’W; P. Laurino et al., 28 Aug. 2004. CTL 1386 , 30; Ruta 9, km 254.8 , 34°13.23’S 53°57.26’W; P. Laurino et al., 27 Aug. 2004. UFRJ 4461 , 1; UFRJ 4460 , 2 (c&s); Ruta 19, between 18 de Julio and San Luis ; J. J. Reichert, no date. CTL 1467 , 3; Ruta 14, km 270, north to Lascano , 33°36.82’S 54°18.00’W; P. Laurino et al., 28 Aug. 2004. CTL 1393 , 9; temporary swamp near Canal Andreoni, Ruta 14, km 504 , 33°55.21’S 53°32.61’W; P. Laurino et al., 27 Aug. 2004. Brazil: Rio Grande do Sul: UFRJ 4982 , 27; UFRJ 5026 , 3 (c&s); UFRJ 6217 , 2; temporary pool km 5.5 of road Chui-Barra do Chui ; W. J. E. M. Costa & A. C. L. H. Bacellar, 12 Sep. 1999.

Diagnosis

Distinguished from all other congeners by a unique color pattern in males, consisting of anterior third of flank pale brown, posterior two thirds silver with 6-11 dark gray to black bars.

Description

Morphometric data appear in Table 1. Males larger than females, the largest male examined 48.3 mm SL, largest female 35.0 mm SL. Dorsal profile convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle; sometimes a small adipose ridge on frontal region in males. Ventral profile slightly 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 moderately slender and 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 of pectoral fin situated on vertical between urogenital papilla and base of 3rd anal-fin ray in males, between pelvic-fin base and anus in females. Tip of each pelvic fin reaching between base of 4th and 5th anal-fin rays in males, between urogenital base of 1st and 3rd anal-fin rays in females. Pelvic-fin bases in close proximity or united, medial membrane sometimes 30 % united in females. Urogenital papilla not attached to anal fin. Dorsal-fin origin on vertical between base of 4th and 7th anal-fin rays in males, between base of 3rd and 4th anal-fin rays in females. Dorsal-fin origin between neural spines of 6th and 9th vertebrae in males, between neural spines of 9th and 12th vertebrae in females. Anal-fin origin between pleural ribs of 8th and 10th vertebrae in males, between pleural ribs of 10th and 13th vertebrae in females. Dorsal-fin rays 22-26 in males, 14-18 in females; anal-fin rays 20-24 in males, 14-19 in females; caudal-fin rays 22-25; pectoral-fin rays 10-12; pelvic-fin rays 5-6.

Scales large and cycloid. Trunk and head 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 usually E-patterned, sometimes F-patterned; E-scales slightly overlapping medially; scales arranged in transverse pattern. Longitudinal series of scales 27-30, scales regularly arranged; transverse series of scales 12-14; scale rows around caudal peduncle 16-18. One prominent contact organ on each scale of ventral portion of flank and opercular region in males. Row of prominent contact organs on each of four or five uppermost pectoral-fin rays, and on distal portion of first two or four anal-fin rays in males. No contact organs on dorsal and caudal fins.

Cephalic neuromasts: supraorbital 13-17, parietal 1 or none, anterior rostral 1, posterior rostral 1, infraorbital 1-2 + 15-20, preorbital 2, otic 2-4, post-otic 3-4, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 12-15, mandibular 8-11, lateral mandibular 2-4.

Basihyal subtriangular, width about 65-80 % of length; basihyal cartilage short, about 25-40 % of total basihyal length, without lateral projections. Six branchiostegal rays. Two to six teeth on second pharyngobranchial. Gill-rakers on first branchial arch 2-3 + 8-10. Dermosphenotic ossification absent. Ventral process of posttemporal usually long, sometimes short. Total vertebrae 27-30.

Coloration

Males: dorsum and anterior third of flank pale brown, posterior two thirds of flank silver, with 6-11 dark gray to black bars, anterior bars narrower than interspace and posterior bars wider or equal in width. Urogenital papilla gray. Opercular and infraorbital regions pale blue; short, black infraorbital bar, subtriangular dark gray supraorbital blotch. Iris yellowish brown, with dark gray bar through center of eye. Unpaired fins dark gray, black on posterior portion of dorsal and anal fins; row of elongated white spots on dorsal and anal-fin bases, often a row of white dots on caudal-fin base; light blue to golden iridescence on dorsal fin and light blue iridescence on anal and caudal fins. Pelvic fins light blue. Pectoral fins light bluish gray.

Females: sides of body light yellowish brown, with narrow dark gray bars or vertical rows of elongated dark gray spots; never darker spots on anterocentral portion of flank and caudal peduncle. Venter pale golden. Opercular region pale greenish golden. Iris light yellow, with gray bar through center of eye. Infraorbital and supraorbital bars gray. Unpaired fins hyaline, sometimes with gray spots on basal portion of whole fins; paired fins hyaline.

Distribution

Southern tributaries to laguna Merín and adjacent coastal river systems, eastern Uruguay (Fig. 11).

Remarks

Austrolebias luteoflammulatus usually is a small species with a slender body, reaching about 30-35 mm SL. However, specimens of two populations from near laguna de Rocha, the westernmost portion of the geographic range of the species, reach about 48 mm SL, and may be moderately deep bodied. As no additional morphological distinguishing features were found, they are considered conspecific.