Hypsolebias tocantinensis

description

Description. Morphometric data presented in Table 1. Largest specimen examined 38.25 mm SL. Body relatively deep, compressed, greatest body depth at level of pelvic fin base. Snout blunt. Urogenital papilla cylindrical and very short in males, pocket-shaped in females. Dorsal profile convex from snout to end of dorsal fin base, slightly concave or straight on caudal peduncle. Ventral profile convex from lower jaw to the end of anal fin base, nearly straight on caudal peduncle. Eyes positioned on upper portion of side of head. Tip of dorsal and anal fin rounded in males and females. Short filamentous ray extensions from 15 th ray on dorsal fin and 7 th ray on anal fin in males; filaments absent in females. Dorsal and anal fin unbranched in males and females. Caudal fin rounded. Pectoral fin elliptical. Posterior margin of each pectoral fin reaching vertical through base of fifth or sixth anal-fin ray in males, and between pelvic fin and urogenital papilla in females. Tip of each pelvic fin reaching base of first anal-fin ray in males and females. Pelvic fin bases close to each other. Dorsal-fin origin between origins of pelvic- and anal-fins in males; anal-fin origin on vertical thr

A new species of annual fish, Hypsolebias tocantinensis sp. n. (Cyprinodontiformes: Rivulidae) from the rio Tocantins basin, northeastern Brazil

diagnosis

Diagnosis. Hypsolebias tocantinensis differs from the remaining species of the H. flammeus species-group, except from H. multiradiatus, H. flammeus (Fig. 3), and H. brunoi (Fig. 4), by the male body color pattern, with reddish brown bars alternating in a bright blue background, by the male’s anal fin being bright blue (vs. pale yellow or brownish red), and by the presence of a metallic blue sheen surrounding the female’s black spots (vs. absence of such a pattern). Hypsolebias tocantinensis differs from all other Hypsolebias by the presence of short extensions in male dorsal and anal fin rays, starting at the 15 th ray in the dorsal fin and 7 th ray in the anal fin (vs. no ray extensions or long extensions in all rays). Hypsolebias tocantinensis is unique among the Cynolebiasini by having irregular light brown markings on the female anal fin. Additionally, H. tocantinensis differs from H. flammeus, H. multiradiatus and H. brunoi by the angle of the reddish brown bars on the body of the male. Whereas H. flammeus H. multiradiatus and H. brunoi have vertical bars, in H. tocantinensis the bars are slightly diagonal, approximately 15 ° from vertical.

A new species of annual fish, Hypsolebias tocantinensis sp. n. (Cyprinodontiformes: Rivulidae) from the rio Tocantins basin, northeastern Brazil

distribution

Distribution (Fig. 5). Known only from the type-locality, a flooded area close to the rio Lajeado, rio Tocantins basin, Maranhão state, Brazil. Habitat (Fig. 6). The temporary pool is located in a flooded area about 200 m from the rio Lajeado, in Campestre do Maranhão. The pool has been altered from its original state as it was cut in half by an interstate highway (Belém-Brasília, BR- 010). Average depth of the pool is 1 m, with deepest portions about 1.5 m, with as lightly acid pH (6.4) and low electric conductivity (0,05 µs). The substrate is composed of clay and sand with slightly dark water. The temperature on the water surface was approximately 27 ºC and, in the deepest portion and banks, approximately 21 ºC. The region’s annual average temperature is 26 ºC, with maximum of 38.2 ºC and minimum of 20.6 ºC. The region has an annual average rainfall of 1400 mm per year, with a rainy season from November to March. Marginal vegetation is composed primarily of grass for cattle pasture (altered from Amazonian Rain Forest). Aquatic vegetation is composed essentially of grass tufts, Echinodorus sp. and Nynphea sp. At the same locality two other rivulids were also found, Pituna compacta

A new species of annual fish, Hypsolebias tocantinensis sp. n. (Cyprinodontiformes: Rivulidae) from the rio Tocantins basin, northeastern Brazil

materials_examined

Holotype. Deposited at Universidade de Campinas, Campinas, São Paulo, Brazil. (ZUEC 7019) male 38.2 mm SL: Brazil, Maranhão, Campestre do Maranhão, temporary pool near rio Lajeado, rio Tocantins basin, 06 º- 05 ' - 12.43 ” S, 047 º- 22 ' - 54.01 ” W, altitude 133 m, 0 1 April 2011. Col. Arsênio Caldeira Baptista Junior and João Carlos da Cruz. Paratypes. Deposited at Universidade de Campinas, Campinas, São Paulo, Brazil. (ZUEC 7020), 1 male (37.4 mm SL), 7 females (27.7 – 31.1 mm SL), collected with the holotype.

A new species of annual fish, Hypsolebias tocantinensis sp. n. (Cyprinodontiformes: Rivulidae) from the rio Tocantins basin, northeastern Brazil