Austrolebias jaegari

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 : 25-27

Austrolebias jaegari Costa & Cheffe

(Fig. 9)

Austrolebias jaegari Costa & Cheffe, 2002: 84 ( type locality: swamp at banhado do Timba, Corredor das Tropas , approximately 31°30’S 52°20’W, Pelotas, Rio Grande do Sul, Brazil; holotype: MCP 28574 ).

Material examined

Brazil: Rio Grande do Sul: Pelotas: MCP 28574 , male holotype, 30.4 mm SL; MCP 28575 , 5 paratypes; CIMC 3538 , 4 paratypes; swamp at Banhado do Timba, Corredor das Tropas , approximately 31°30’S 52°20’W; M. Cheffe, G. Maurício & N. Jaegar, 30 Aug. 2000. UFRJ 5429 , 7 paratypes; UFRJ 5430 , 6 paratypes (c&s); same locality ; M. Cheffe & F. Silveira, 23 Aug. 2000. CIMC 3583 , 5 paratypes; same locality ; M. Cheffe & F. Silveira, 22 Oct. 2000. CIMC 3518 , 5 paratypes; arroio Santa Barbara floodplains ; M. Cheffe, 23 Aug. 2000.

Diagnosis

Similar to A. gymnoventris ,from which it is distinguished by having longer pectoral fins (26.3-29.2 % SL in males, 27.8-29.9 % SL in females, vs. 23.9-26.0 % SL in males and 24.9-26.6 % SL in females), anal-fin origin between pleural ribs of 6th and 8th vertebrae in males (vs. between pleural ribs of 8th and 10th vertebrae), dorsal-fin origin on vertical between pectoral-fin base and anus in males (vs. on vertical through pelvic-fin base or anterior to it), and anterior light bars of flank in males narrower (widest bar 1.7-2.2 % SL, vs. 2.5-3.2 % SL).

Distinguished from all other congeners by the combination of absence of scales on venter (vs. entire venter covered with scales), absence of suborbital and supraorbital dark marks in live specimens (vs. conspicuous dark grey to black supraorbital and suborbital bars), and flank side dark brownish gray to black with light grey bars on anterior portion, and without brilliant colors in males (vs. never a similar color pattern).

Description

Morphometric data appear in Table 1. Males larger than females, the largest male examined 30.4 mm SL, largest female 28.5 mm SL. Dorsal profile nearly straight to slightly concave on head, convex from nape to end of dorsal-fin base, approximately straight on caudal peduncle; no 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 moderately deep and compressed. Snout blunt, 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 through base of 6th anal-fin ray in males, through urogenital papilla in females. Tips of pelvic fins reaching base of 3rd anal-fin ray in males. Pelvic-fin bases in close proximity or united, medial membrane not coalesced. Urogenital papilla not attached to anal fin. Anal-fin origin on vertical through base of 3rd or 4th dorsal-fin ray. Dorsal-fin origin between neural spines of 5th and 7th vertebrae in males, between neural spines of 9th and 10th vertebrae in females. Anal-fin origin between pleural ribs of 6th and 8th vertebrae in males, between pleural ribs of 9th and 10th vertebrae in females. Dorsal-fin rays 22-26 in males, 18-21 in females; anal-fin rays 21-23 in males, 17-21 in females; caudal-fin rays 20-23; pectoral-fin rays 12; pelvic-fin rays 5.

Scales large and cycloid. Trunk and head scaled, except venter, ventral surface of head, and preopercular region; squamation reduced on opercle. No scales on dorsal and anal-fin bases, and two rows of scales on caudal-fin base. Frontal squamation E- or F- patterned; E-scales slightly overlapping medially; scales arranged in transverse pattern. Longitudinal series of scales 26-27, the scales regularly arranged; transverse series of scales 12; scale rows around caudal peduncle 16. One prominent contact organ on each scale of anteroventral portion of flank and opercular region in males. Row of minute contact organs on two uppermost pectoral-fin rays. No contact organ on unpaired fins.

Cephalic neuromasts: supraorbital 13-16, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital 1-2 + 16-17, preorbital 2, otic 2, post-otic 3-4, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 13-14, mandibular 10-11, lateral mandibular 4.

Basihyal subtriangular, width about 75 % of length; basihyal cartilage moderate, about 50 % of total basihyal length, with slight lateral projections. Six branchiostegal rays. Two to four teeth on second pharyngobranchial. Gill-rakers on first branchial arch 2 + 8-9. Dermosphenotic ossification absent. Ventral process of posttemporal short, sometimes vestigial. Total vertebrae 27-29.

Coloration

Males: sides of body dark brownish gray, with 6-9 light gray bars; anterior bars lighter and wider than posterior ones, 1.7-2.2 % SL; anterior bars approximately half interspace width, posterior bars substituted by vertical series of dots on caudal peduncle. Urogenital papilla blue. Opercular and infraorbital regions bright blue; infraorbital and supraorbital absent, sometimes scarcely visible. Iris yellowish brown, with gray bar through center of eye. Unpaired fins dark brown with orange iridescence and white dots on basal portion of fins; intense bright blue iridescence on distal portion of anal fin, forming distinctive stripe. Pelvic fins bright blue. Pectoral fins hyaline.

Females: sides of body light yellowish brown, with vertically elongated dark gray spots, sometimes forming short bars; 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 absent. Unpaired fins hyaline, with dark gray spots on whole fins, darker on basal portion of dorsal and anal fins; paired fins hyaline.

Distribution

River basins associated with southern inner shore of laguna dos Patos, southern Brazil (Fig. 8).