Austrolebias litzi, 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 : 80-83

Austrolebias litzi , new species

(Fig. 32)

Material examined

Holotype. UFRJ 6233 , male, 38.2 mm SL; Brazil: Rio Grande do Sul: 2.5 km of arroio Arenal, about 12 km from Santa Maria, road BR-392 ; W. J. E. M. Costa & A. C. Bacellar, 31 Aug. 1999.

Paratypes. Brazil: Rio Grande do Sul: UFRJ 5028 , 18 males, 17.2-33.8 mm SL, 18 females, 17.6-30.8 mm SL; UFRJ 5029 , 4 males, 26.8-34.1 mm SL, 2 females, 25.2-31.3 mm SL (c&s); collected with holotype . UFRJ 4987 , 66 males, 16.0-33.6 mm SL, 125 females, 15.6-29.8 mm SL; UFRJ 5017 , 2 males, 31.9-35.8 mm SL, 2 females, 23.5-26.1 mm SL (c&s); 1 km of arroio Arenal, about 10.5 km from Santa Maria, road BR-392 ; W. J. E. M. Costa & A. C. Bacellar, 31 Aug. 1999. UFRJ 4488 , 3 males, 20.5-27.9 mm SL, 8 females, 22.8-24.1 mm SL; floodplains of a stream tributary of rio Vacacai , 6 km NW of Vila Block, road BR-392 ; W. J. E. M. Costa, D. Belote & R. D’Arrigo, 13 Sep. 1997.

Diagnosis

Similar to A. cyaneus and distinguished from all other congeners of the A. alexandri species group in having small round spots on flank in females, spots always smaller than eye and separated among themselves by broad space (vs. never a similar color pattern). Distinguished from A. cyaneus by possessing flanks bluish gray, with 8-15 vertical rows of bright blue dots in males (vs. approximately black with 12-22 vertical rows of bright blue dots), bright dots of unpaired fins in males restricted to basal half of fins (vs. on whole fins, often forming subdistal series of close dots on dorsal fin), and basihyal cartilage about 55 % basihyal length (vs. about 75 %).

Description

Morphometric data appear in Table 5. Males larger than females, largest male examined 38.2 mm SL, largest female 30.8 mm SL. Dorsal profile convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle; sometimes a weak adipose ridge on frontal region of head in males. 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 and jaws short.

Tip of both dorsal and anal fins 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 bases of 3rd and 5th anal-fin rays in males, between anus and urogenital papilla in females. Tip of each pelvic fin reaching between base of 2nd and 3rd anal-fin rays in males, between urogenital papilla and base of 2nd anal-fin ray in females. Medial pelvic-fin bases in close proximity. Urogenital papilla not attached to anal fin. Anal-fin origin on vertical between bases of 1st or 3rd dorsal-fin rays; dorsal-fin origin between neural spines of 7th and 9th vertebrae in males, between neural spines of 9th and 11th vertebrae in females. Anal-fin origin between pleural ribs of 8th and 9th vertebrae in males, between pleural ribs of 10th and 11th vertebrae in females. Dorsal-fin rays 20-25 in males, 16-20 in females; anal-fin rays 21-26 in males, 18-21 in females; caudal-fin rays 25-28; pectoral-fin rays 11-12; pelvic-fin rays 5.

Scales large and cycloid. Trunk and head entirely 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 H-patterned; E-scales overlapping medially; scales arranged in transverse pattern. Longitudinal series of scales 26-27, scales regularly arranged; transverse series of scales 12-13; scale rows around caudal peduncle 16. One contact organ on each scale of ventral portion of flank in male. Rows of small contact organs on one or two uppermost pectoral-fin rays in male. No contact organ on anal, dorsal and caudal fins.

Cephalic neuromasts: supraorbital 14-16, parietal 2-3, anterior rostral 1, posterior rostral 1, infraorbital 2 + 20-21, preorbital 1-2, otic 2, post-otic 3, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 17-19, mandibular 9-10, lateral mandibular 3-4.

Basihyal subtriangular, width about 60 % of length; basihyal cartilage long, about 55 % of total basihyal length, without lateral projections. Six branchiostegal rays. Two to four teeth on second pharyngobranchial. Gill-rakers on first branchial arch 2-3 + 8-10. Dermosphenotic ossification absent. Ventral process of posttemporal vestigial or absent. Total vertebrae 26-28.

Coloration

Males: side of body bluish gray, with 8-15 rows of bright blue dots, anterior dots united forming narrow vertical lines. Urogenital papilla gray. Opercular and infraorbital regions bright blue; nearly rectangular dark gray infraorbital bar; subtriangular dark gray supraorbital blotch, not reaching neuromast parietal series. Iris yellow, with blue border and black bar through center of eye. Unpaired fins dark gray, with two irregular rows of bright blue dots on basal half of fins; pink or golden iridescence on distal portion of dorsal fin; intense bright blue iridescence on distal portion of anal fin, often forming distinctive stripe; bright blue iridescence on distal portion of caudal fin. Paired fins bright blue.

Females: sides of body light yellowish brown, with dark gray small spots always smaller than eye; spots on anterocentral portion of flanks and posterior portion of caudal peduncle often darker, sometimes black; venter pale golden. Opercular region pale greenish golden. Iris light yellow, with gray bar through center of eye. Infraorbital and supraorbital bars dark gray. Unpaired fins hyaline, with dark gray spots on basal portion; paired fins hyaline.

Distribution

Upper rio Jacuí drainage, laguna dos Patos system, Rio Grande do Sul, southern Brazil (Fig. 20).

Etymology

Named in honor of Thomas Litz, in recognition of his enthusiasm and efforts in collecting Austrolebias material.