Austrolebias apaii, 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 : 108-111

Austrolebias apaii Costa, Laurino, Recuero & Salvia, new species

(Fig. 42)

Cynolebias bellottii non C. bellottii Steindachner; Vaz-Ferreira & Sierra, 1971: 24 (misidentification of specimens from western Uruguay).

Material examined

Holotype. MUNHINA 3216 , male, 41.8 mm SL; Uruguay: Colonia: Carmelo , 34°00.31’S 58º17.00’W; P. Laurino, F. I. Prieto, H. Salvia & J. Salvia, 12 Sep. 2004.

Paratypes. Uruguay: Colonia: UFRJ 6226 , 7 males, 29.6-40.8 mm SL, 7 females, 27.8-32.8 mm SL; MUNHINA 3217 , 19 males, 23.4-39.6 mm SL, 40 females, 21.9-31.0 mm SL; collected with holotype . Soriano: UFRJ 6227 , 4 males, 28.0-34.7 mm SL, 2 females, 25.3-33.4 mm SL (c&s); ZSM 33650 , 38 males, 17.1-37.8 mm SL, 64 females, 22.4-35.9 mm SL; Ruta 96, km 8 , 33°26.30’S 58º16.59’W; P. Laurino, F. I. Prieto, H. Salvia & J. Salvia, 12 Sep. 2004.

Additional material (non types). Argentina: Província de Entre Ríos: MLP 8306 , 4; La Salamanca, Concepcion del Uruguay ; A. Bachmann, 8 Apr. 1961. Uruguay: Colonia: MCP 15052 , 4; swamp in front of Cassino de Carmelo ; R. Vaz-Ferreira, B. Sierra & J. S. Soriano, 21 Aug. 1965.

Diagnosis

Differs from all other species of the A. bellottii group in having the anal-fin origin situated between pleural ribs of 5th and 7th vertebrae in males, and between pleural ribs of 7th and 8th vertebrae in females (vs. between pleural ribs of 7th and 10th vertebrae in males, between pleural ribs of vertebrae 9th and 11th in females). Differs from all congeners, except A. bellottii , A. univentripinnis , and A. melanoorus , in having the entire urogenital papilla attached to the anal fin in males (vs. urogenital papilla free from the anal fin); from A. univentripinnis in having more teeth on the second pharyngobranchial (8-12 vs. 6-8), more supraorbital neuromasts (20-24 vs. 17-18), more preopercular plus mandibular neuromasts (43-47 vs. 39-41); from A. bellottii by possessing a longer anal-fin base in males (50.8-54.8 % SL, vs. 44.9-50.8 % SL), larger eye in males (29.2-33.1 % head length, vs. 25.4-28.6 % head length), usually having more vertical rows of bright dots on the flank in males (11-18 vs. 7-12), and dorsal-fin origin between neural spines of 6th and 8th vertebrae in males, between neural spines of 9th and 11th vertebrae in females (vs. between neural spines of 8th and 10th vertebrae in males, between neural spines of 11th and 12th vertebrae in females); from A. melanoorus by possessing distinct color patterns: flanks dark bluish gray with vertical rows of bright greenish blue dots in males (vs. light bluish gray bars alternating with dark gray bars), unpaired fins with bright dots in males (vs. elongate light spots and bright lines parallel to fin rays), and females sometimes with 1-3 black spots on center of the flank, often black spots absent (vs. always 5-16 black spots).

Description

Morphometric data appear in Table 7. Males larger than females, largest male examined 41.8 mm SL, largest female 32.8 mm SL. Dorsal profile slightly concave on head, convex from nape to end of dorsal-fin base, nearly straight on caudal peduncle; often prominent adipose ridge on frontal region in males. Ventral profile convex from lower jaw to end of anal-fin base, approximately straight on caudal peduncle. Greatest body depth at level of pelvic-fin base. Body deep and compressed. Snout blunt and jaws short.

Tip of both dorsal and anal fins rounded. Anteromedian rays of anal fin of females lengthened, anal fin shape approximately triangular; distal portion of anal fin thickened in females. Caudal fin rounded. Pectoral fins elliptical, posterior margin on vertical between base of 6th and 8th anal-fin rays in males, and between base of 2nd and 7th anal-fin rays in females. Tip of both pelvic fins reaching between base of 4th and 5th anal-fin rays. Medial pelvic-fin membranes about 60-75 % coalesced. Entire urogenital papilla attached to anal fin in males. Dorsal-fin origin on vertical between base of 2nd and 5th anal-fin rays in males, between base of 2nd and 4th anal-fin rays in females; dorsal-fin origin between neural spines of 6th and 8th vertebrae in males, between neural spines of 9th and 11th vertebrae in females. Anal-fin origin between pleural ribs of 5th and 7th vertebrae in males, between pleural ribs of 7th and 8th vertebrae in females. Dorsal-fin rays 22-26 in males, 17-22 in females; anal-fin rays 29-32 in males, 26-29 in females; caudal-fin rays 21-25; pectoral-fin rays 11-12; pelvic-fin rays 5-6.

Scales large and cycloid. Trunk and head entirely scaled, except ventral surface of head. One row of scales on anal-fin base, no scales on dorsal-fin base, and three rows of scales on caudal-fin base. Frontal squamation usually G-patterned, sometimes H or F- patterned; E-scales not or slightly overlapping medially; scales arranged in transverse pattern. Longitudinal series of scales 30-32; transverse series of scales 12-14; scale rows around caudal peduncle 16-18. Four to six minute contact organs on each scale of ventral portion of flank and opercular region in male. Row of small contact organs on two uppermost pectoral-fin rays. No contact organs on unpaired fins.

Cephalic neuromasts: supraorbital 20-24, parietal 2-5, anterior rostral usually 1, rarely 2, posterior rostral 1, infraorbital 3 + 22-30, preorbital 3, otic 4, post-otic 7, supratemporal 1, median opercular 1, ventral opercular 3-4, preopercular 27-31, mandibular 15-16, lateral mandibular 6-8.

Basihyal nearly triangular, width about 55 % of length; basihyal cartilage long, about 60 % of total basihyal length, with pronounced lateral projection. Six branchiostegal rays. Urohyal deep. Eight to twelve teeth on second pharyngobranchial. Gill-rakers on first branchial arch 4 + 11-12. Sometimes one or two minute dermosphenotic ossifications. Ventral process of posttemporal long. Total vertebrae 28-31.

Coloration

Males: sides of body dark bluish gray, with 11-18 vertical rows of light blue dots. Side of head dark greenish gray to bright blue on opercular and infraorbital region; approximately rectangular, broad black infraorbital bar, ventral tip directed ventroposteriorly; subtriangular black supraorbital bar, not extending to parietal series of neuromasts. Iris dark brownish yellow, with black bar through center of eye. Dorsal fin dark bluish gray, with two rows of white dots on basal half. Anal fin dark bluish gray, often with light blue iridescence; transverse row of white dots on basal portion and black distal line. Caudal fin dark bluish gray, with white dots on basal half; marginal region hyaline. Pelvic fins dark bluish gray, with black tip. Pectoral fins hyaline, with dark bluish gray ventral margin.

Females: sides of body light yellowish brown, with vertically elongate dark gray spots, often vertically arranged, sometimes forming bars; often one to three two black spots on anterocentral portion of flanks, never black spots on caudal peduncle; venter pale yellow. Opercular region pale greenish blue. Pale gray supraorbital and infraorbital bars. Iris light yellow, with gray bar through center of eye. Unpaired fins hyaline, with dark gray small spots, darker and elongated on dorsal portion of dorsal and anal fins; paired fins hyaline.

Distribution

Río Uruguay floodplains, Uruguay and Argentina (Fig. 11).