Austrolebias jaegari, Costa & Cheffe, 2002

Costa, Wilson J. E. M. & Cheffe, Morevy M., 2002, Austrolebias jaegari (Cyprinodontiformes: Rivulidae: Cynolebiatinae): a new annual fish from the Laguna dos Patos system, southern Brazil, with a redescription of A. gymnoventris (Amato), aqua, Journal of Ichthyology and Aquatic Biology 6 (2), pp. 83-88 : 84-86

Austrolebias jaegari n. sp.

(Figs. 1 -2; Table l)

Holotype: MCP 28574 , male, 30.4 mm SL; Brazil: Rio Grande do Sul: Pelotas: swamp at Banhado do Timba , Corredor das Tropas , approximately 31 ° 30 ' S 52 ° 20' W; collected by M. Cheffe, G. Maurício & N. Jaegar, 30 August 2000, with a dip net.

Paratypes: Brazil: Estado do Rio Grande do sul; Pelotas: MCP 28575 , l male, 23.5 mm SL, and 4 females, 21.1 -23.4 mm SL, MUCP 2538 , 4 males, 20.9 -29.9 mm st; all ccllected with holotype. UFRJ 5429 , 1 male, 26.6 mm SL; and 6 females, 21.0 - 22.5 mm SL UFRJ 5430 , 3 males, 28.4- 29.9 mm SL, and 3 females, 23.9 -25.7 mm SL (c&s); same locality; M. Cheffe & F. Silveira, 23 August 2000. MUCP 2583 , 5 females, 21. 5-28.5 mm SL same locality; collected by M. Chetfe & F. Silveira, 22 October 2000. MUCP 2518 , 2 males, 25.9-27.1 mm SL, and 3 females, 22.2 -23.5 mm SL; Arroio Santa Bárbara floodplains, approximately; collected by M Cheffe, 23 August 2000. All paratypes collected with a dip net.

Diagnosis

Similar to A. gymnoventris and distinguished from all other congeneres by lacking scales on venter (vs. scales covering whole venter), body contact Organs restricted to anteroventra| portion of male body side (vs. contact organs over whole ventral half of flank), absence of suborbital and supraorbital dark marks in live specimens (vs. conspicuous dark grey to black supraorbital and suborbital bars), and male body side dark brownish grey with tight grey bars on anterior portion, becoming narrow and faint on the posterior portion (vs. never a similar colour pattern). lt differs from A. gymnoventris by having papillate contact organs on pectoral fin of male (vs. no papillate contact organs on pectoral fin), longer pectoral fin (26.3-29.2 % SL in male and 27.8-29.9% SL in female, vs. 23.9- 25.9 % SL in male and 24.9 -26.6% SL in female), anal fin origin of male between pleural ribs of vertebrae 6 and 8 (vs. between pleural ribs of vertebrae 8 and 10), dorsal fin origin of male in a vertical between pectoral fin base and anus (vs. vertical through pelvic-fin base or anterior to it), and anterior light body bars of male narrower (widest bar 1.7-2.2% SL, vs. 2.5-3.2% SL).

Description

Morphometric data for holotype and nine paratypes are given in Table I . Male larger than female, largest male 30.4 mm SL. Dorsal profile approximately straight to slightly concave on head, convex between snout and dorsal fin base end, approximately straight on caudal peduncle. Ventral profile convex from lower jaw to end of anal fin base, nearly straight on caudal peduncle. Body slender, compressed, maximum body width approximately 1.9 in maximum body depth in larger males. Greatest body depth at vertical through dorsal fin origin. Snout blunt, jaws short.

Tip of dorsal and anal fins rounded. Anteromedian rays of anal fin of female not lengthened, anal fin profile approximately semicircular. 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 sixth anal fin ray in male, and urogenital papilla in female. Tip of pelvic fin reaching base of third anal fin ray. Pelvic fin bases in close proximity, but fins not medially united. Dorsal fin origin on a vertical between pelvic fin base and anus in male, and between anus and urogenital papilla in female. Anal fin origin on a vertical through base of third or fourth dorsal fin ray, and between pleural ribs of ver ­ tebrae 6 and 8 in male, and through base of third dorsal fin ray and between pleural ribs of vertebrae 9 and 10 in female. Dorsal fin rays 22-26 in male, 18-21 in female; anal fin rays 21 -23 in male, 17-21 in female; caudal fin rays 20-23; pectoral fin rays 12; pelvic fin rays 5.

Scales large, cycloid. Lateral and dorsal surface of body and head entirely scaled; no scales on ventral surface of head and venter, except for some scales just anterior to pelvic fin base, sometimes also absent. Frontal squamation E or F-patterned. No transverse row of scales on anal and pectoral fin bases. Longitudinal series of scales 26-27; transverse series of scales 12; scale rows around caudal peduncle 16. One prominent cteniform contact organ on each scale of anteroventral portion of body side of male, below lateral line of neuromasts. No contact organs on fins, except a few minute ones on inner surface of distal portion of first and second most dorsal pectoral fin ray of male. Supraorbital neuromasts 12- 15.

Autopalatine with small, rounded dorsomedial projection. Basihyal triangular, its longest width about 75% its length; basihyal cartilage long, about 50 % total basihyal length, with slight lateral projection. S ix branchiostegal rays. Two to four teeth on second pharyngobranchial. Gill-rakers on first branchial arch 2 + 8-9. Posterior arm of parasphenoid narrow. Der - mosphenotic absent. Ventral process of posttemporal short, sometimes vestigial. Total vertebrae 27-29.

Coloration: Male: Side of body dark brownish grey, with six to nine light grey bars; widest bar 1.7-2.2% SL; anterior four bars in close proximity, separated by neighbouring bars by space twice wider than bar width; posterior bars faint, narrower, substituted by vertical series of dots on caudal peduncle, and sepa ­ rated among themselves by broad space, about seven times bar width. Dorsum dark brownish grey. Head bright blue; suborbital and supraorbital bars absent, but faint suborbital bar present in preserved specimens. Iris brown; faint grey bar through eye. Dorsal fin dark brownish grey with orange-pink irides ­ cence and white dots. Caudal and anal fins dark brownish grey with white dots on basal region; broad bright blue zone along distal border of anal fin; dorsal portion of caudal fin with orange-pink iridescence. Pectoral fin hyaline. Pelvic fin bright blue.

Female: Side of body light brown, with dark grey spots, usually vertically elongated; no distinctive darker spots on anterocentral portion of flank. Venter pale golden. Head light brown, opercular region pale golden; suborbital or supraorbital bars absent. Iris yellow. Unpaired fins hyaline; faint, small grey spots on unpaired fins, becoming dark grey on dorsal and anal fin bases.

Etymology

The name jaegari is in honour of the late photographer Norberto Henrique Jaegar, in recognition of his enthusiasm and dedication to the conservation of natural areas.

Distribution

Known from the type locality region, the floodplains of the southern inner shore of Laguna dos Patos, southern Brazil ( Fig. 3 ). This species was previously collected by Roberto Krebs Baltar, in 1972, Capão do Leão, about 15 km W from the type locality, but no material was preserved for study.

Figures

Fig. 3. Geographic distribution of A.jaegari and A. gymnoventris.