Cynolebias parnaibensis

description

Description. Morphometric data in Table 1. Dorsal and ventral profiles convex between snout and anterior part of caudal peduncle, nearly straight on caudal peduncle. Body moderately deep, slightly compressed, greatest body depth at level of vertical just anterior to pelvic-fin base. Snout short, blunt. Dorsal and anal fins pointed in males, rounded in females. Pectoral fin long, rounded, reaching vertical between base of 2 nd and 4 th anal-fin rays in males, and between pelvic-fin base and anus in females. Tip of pelvic fin reaching between base of 2 nd and 3 rd anal-fin rays in males, reaching between urogenital papilla and anal-fin origin in females. Pelvic-fin bases medially separated by small interspace. Dorsal-fin origin through base of 5 th or 6 th anal-fin ray in males, and above base of 4 th or 5 th anal-fin ray in females; dorsal-fin origin between neural spines of vertebrae 15 and 17 in both sexes. Anal-fin origin between pleural ribs of vertebrae 11 and 12 in males, and pleural ribs of vertebrae 13 and 14 in females. Dorsal-fin rays 16 - 18 in males, 15 - 16 in females; anal-fin rays 19 in males, 18 - 21 in females; caudal-fin rays 28 - 31; pectoralfin rays 13 - 14; pelv

Cynolebias parnaibensis, a new seasonal killifish from the Caatinga, Parnaíba River basin, northeastern Brazil, with notes on sound producing courtship behavior (Cyprinodontiformes: Rivulidae)

diagnosis

Diagnosis. Cynolebias parnaibensis is distinguished from all other species of the genus, except C. griseus and C. gilbertoi, by having 27 - 31 neuromasts around eye (vs. 33 - 46). The new species differs from C. griseus by having 29 - 33 supraorbital neuromasts (vs. 19 - 22), 16 - 18 dorsal-fin rays and 19 anal-fin rays in males (vs. 20 - 22 and 21 - 23, respectively), 28 - 31 caudalfin rays (vs. 33 - 34), 6 pelvic-fin rays (vs. 5), dorsal-fin origin at a vertical between the base of the 4 th or 6 th anal-fin ray (vs. base of 1 st or 2 nd ray), 33 - 36 scales in the longitudinal series (vs. 29 - 31), 3 + 10 gill-rakers in the first branchial arch (vs. 5 + 15), absence of second pharyngobranchial teeth (vs. presence), absence of the ventral uncinate process of the second epibranchial (vs. presence), absence of the ventral limb of the posttemporal (vs. presence), and absence of contact organs on the flank scales in both sexes (vs. presence in males). From C. gilbertoi it differs by having 34 - 35 vertebrae (vs. 32 - 33), and by the absence of teeth on vomer (vs. 13 - 15 vomerine teeth). Cynolebias parnaibensis is also distinguished from C. griseus, C. gilbertoi, C. microphthalmus and

Cynolebias parnaibensis, a new seasonal killifish from the Caatinga, Parnaíba River basin, northeastern Brazil, with notes on sound producing courtship behavior (Cyprinodontiformes: Rivulidae)

distribution

Distribution and habitat. Cynolebias parnaibensis is known from the type locality, a seasonal lagoon close to the road between Conceição de Canindé and Jacobina do Piauí, Município de Jacobina do Piauí, Piauí State, northeastern Brazil. The type locality is inserted in the Caatinga domain, a semi-arid phytogeographic formation, typical of northeastern Brazil. The lagoon is within the Canindé River drainage, which is part of the Parnaíba River basin. It was about 60 m long, 15 m wide, maximum depth 1 m, average depth 50 cm. The water was turbid, light brown, and the bottom was sandy-muddy. Emerging aquatic vegetation occurred in moderate amount, scattered over the lagoon surface, while large amount of submerged vegetation was found, predominating species of the family Hydrocharitaceae. Margins of the pond were in part densely covered by bushes and low vegetation.

Cynolebias parnaibensis, a new seasonal killifish from the Caatinga, Parnaíba River basin, northeastern Brazil, with notes on sound producing courtship behavior (Cyprinodontiformes: Rivulidae)

etymology

Etymology. The name parnaibensis is a reference to the unique occurrence in the Parnaíba River basin among species of the genus Cynolebias.

Cynolebias parnaibensis, a new seasonal killifish from the Caatinga, Parnaíba River basin, northeastern Brazil, with notes on sound producing courtship behavior (Cyprinodontiformes: Rivulidae)