Bufo fernandezae (lesser common toad). Body Temperature.

SANABRIA, EDUARDO; QUIROGA, LORENA; SCARABOTTI, PABLO AUGUSTO; LÓPEZ, JAVIER ALEJANDRO

HERPETOLOGICAL REVIEW

Society for the Study of Amphibians and Reptiles

Año: 2007 vol. 38 p. 180 - 180

0018-084X

BUFO FERNANDEZAE (Lesser Common Toad). BODY TEMPERATURE. Bufo fernanclezae is a typical inhabitant of the northeastern Argentina, and is also found in Paraguay and Uruguay (Cei 1980. Amphibians of Argentina. Monitore Zool. Ital., N. S. Monografia 2, 609 pp.). The thermal ecology of this toad is unknown. To study the thermoregulatory strategy of this species we measured the relationships between cloaca1 temperature (CT), snout-vent length (SVL), air temperature (AT), and substrate temperature (ST) of individuals of this species in natural microhabitats. The study area was a permanent pond in the floodplain of the Middle Parani River in Santo Tom6 city, Santa Fe Province, Argentina (3 199´1 5.7"S, 60q5´35.3" W). The shore was largely covered with grass and Solarzum glaucophyllum while the shallow areas were covered with Ludwigia peploides. Eleven individuals (SVL 5.5 ± 2.08 cm; mean ± SD) were captured between 1900 and 2200 h on 23 Nov 2005 in different microhabitats, including grass, mud, and shallow water. For each specimen, CT, ST, and AT were measured where the individual was collected with a digital thermocouple thermometer (Barnant model 600- 1040). Mean CT was 22.2 ± 1.3"C (N = 11, range 18.8-23.7"C). There were significant differences between ST and AT measured in each site (Mann Whitney, U = 14, N = 11, p < 0.002). CT differed significantly from AT (Mann Whitney, U = 2 1, N = 1 1, p < 0.009) but did not differ from ST (Mann Whitney; U = 0.43, N = 11, p > 0.25). CT showed a positive lineal association with ST (Spearman, R = 0.69; p < 0.01), but not with AT (Spearman, R = 0.27; p > 0.47). No association between the TC and SVL was observed (p > 0.07). These results show that B. ferrzandezae analyzed in this study were predominantly thermopassive, following a mechanism in which the individuals do not actively invest time and energy selecting microhabitats for thermoregulation (Labra y Vidal M. 2003. In: Francisco Bozinovic [ed.]. Fisiologia Ecol6gica y Evolutiva, pp. 207-224. Ediciones Universidad Cat6lica de Chile. Santiago, Chile). The body temperat~lreo f this species depends primarily on the substrate temperature.