Water balance of Atelopus carrikeri (Anura: Bufonidae)

To estimate water lost rates (WLR), we used 15 individuals of Atelopus carrikeri. Individuals were weighed and kept under water absorption overnight. After 12 hours, the individuals were dried with absorbent paper and their urine was extracted by lightly pressing their abdomen and weighed again; to establish and standardize 100% water absorption in all individuals. Next, each specimen was dehydrated with the help of wind tunnels (with a constant wind speed of 2.4 cm s -1), which allowed reaching hydration levels of up to 65% of body mass. The individuals were removed from the wind tunnels at intervals of five minutes (Titon et al., 2010), dried with absorbent paper and weighed. The water loss rate per area (WLR) was estimated from the value of the regression of the weight lost over time and expressed in mg min-1 and divided by 2/3 of the dorsal surface that corresponds to the region of the body in contact with the air flow (mg cm -2 min -1) (Withers et al., 1982; Titon et al., 2010; Titon and Gomes, 2015). To estimate water absorption rates (WAR), after the dehydration experiments, the same individuals were used. They were placed in individual containers with absorbent towels moistened with enough water to cover the ventral region. The individuals were dried and weighed every four minutes for six consecutive times (Titon et al., 2010; Anderson et al., 2017). The water absorption rate per area (TAA), was calculated from the value of the regression of the body weight gained as a function of time (mg min -1), and in turn divided by 1/3 of the total surface area that corresponds to the ventral area in contact with water during absorption, the values were expressed in units of mg cm -2 min -1 (Withers et al., 1982; Titon et al., 2010; Prates et al., 2013; Titon and Gomez, 2015).