Bioacoustics of Pleurodema cordobae

Diagnosis. A small species of Pleurodema ( 35.41 mm SVL) with lumbar glands and chromosomic complement octoploid. The new species is distinguished from other species of the genus Pleurodema by the following combination of characters: (1) relatively small size; (2) snout short, canthus rostralis rounded in dorsal view and truncate in lateral view; (3) lumbar glands present, 1 ½ eye diameter; (4) round tympanic annulus, almost concealed; (5) tympanum length half of the eye diameter; (6) vomerine teeth absent, (7) comissural gland prominent; (8) brilliant red-orange spots on the groin and around lumbar glands; (9) ploid level 2n= 8x =88; (10) axillary amplexus; (11) egg deposition in gelatinous nest attached to vegetation; (12) compound advertisement call with tri-pulsed pulse groups, average dominant frequency 1787 Hz. According to external morphology, Pleurodema kriegi , Pleurodema bibroni and Pleurodema cordobae sp. nov. are cryptic and the properties of their advertisement calls are very similar. Pleurodema cordobae sp. nov. is the only octoploid species of the genus ( P. k r i e g i and P. bibroni are tetraploid and the rest of species are diploid; Brum-Zorrilla & Sáez, 1968 ; Barrio & Rinaldi de Chieri, 1970 ; Veloso et al ., 1972 ; Duellman & Veloso, 1977 ; Schmid et al. , 1993 ; Lourenço et al. , 2006 ). Morphometric comparisons indicate differences between Pleurodema cordobae sp. nov. and P. k r i e g i ( Table 1 ). However, there are no morphometric measures that allow a precise identification between both taxa . The temporal variables of the advertisement call differ from P. k r i e g i ( Table 2 ) and the pulse rate is higher than P. k r i e g i . The erythrocyte size of Pleurodema cordobae sp. nov. is significantly bigger than P. k r i e g i (Table 4) near 100 µm2.

Distribution. The species is currently known from Terra typica , Estancia Los Tabaquillos ( Fig. 1 ) and two temporary ponds located 5 kilometers away from the former. Ecology. Pleurodema cordobae sp. nov. males were acoustically active from December to March (Austral summer) from 21.00 hs. to 4.00 hr. (sunset time: 21.00 – 21.30 hr) Pleurodema cordobae breeds in temporary and semipermanent ponds with vegetation at the edges and a depth of 20 to 30 cm ( Fig. 12 ). The males emit their calls floating on the surface of the water near the edge of ponds ( Fig. 13 ). The eggs are deposited in semisubmerged eggs-masses and adhered to the vegetation ( Fig. 14 ). The amplexus is axillary. This species was observed in syntopy with Rhinella achalensis , R. arenarum , Odontophrynus achalensis and Hypsiboas cordobae .