. The Australian zoologist. Zoology; Zoology; Zoology. R. S. SEYMOUR and A. K. LEE lOr i 03 L. Ilanensis. w _i km 3 x x J 1—/ / I // 1 1 //—i_ 13 5 7 9 18 25 26 150 Days Fig. 2. Evaporative water loss of Lepidobatrachus Ilanensis related to number of days exposed to room air. Cocoons were visible after three days. X symbolize values from two frogs after about five months under dried soil. Data from McClanahan et al. (197r4). water loss by producing a cocoon. Short-term experiments by Warburg (1965, 1967) suggest that EWL decreases with time in Neobatrachus pictus, N. centralis, Limnodynastes d
. The Australian zoologist. Zoology; Zoology; Zoology. R. S. SEYMOUR and A. K. LEE lOr i 03 L. Ilanensis. w _i km 3 x x J 1—/ / I // 1 1 //—i_ 13 5 7 9 18 25 26 150 Days Fig. 2. Evaporative water loss of Lepidobatrachus Ilanensis related to number of days exposed to room air. Cocoons were visible after three days. X symbolize values from two frogs after about five months under dried soil. Data from McClanahan et al. (197r4). water loss by producing a cocoon. Short-term experiments by Warburg (1965, 1967) suggest that EWL decreases with time in Neobatrachus pictus, N. centralis, Limnodynastes dumerili, L. ornatus and Cy dor ana spp. All of these frogs probably produce cocoons. However, Packer (1963), found no change in the rate of EWL from Heleioporus eyrei over a period of six days in dry sand. It is not known if Heleioporus spp. produce cocoons during dormancy. None of the experiments on EWL of Australian anurans was directed toward an assessment of the effect of changes in the skin so none is conclusive. We feel that more work is needed to determine the role of the cocoon on water loss as well as gas exchange and water uptake. The cocoons of the Australian frogs which have been examined are continuous over the eyes and the cloaca, but the nostrils remain open. Seymour (1973c) has shown that all gas exchange occurs cutaneously in dormant spadefoot toads {Scaphiopus) without cocoons, but it is possible that the buildup of shed skin limits respiratory gas exchange to a point necessitating pulmonary ventilation. The cocoons may also function to limit contact of the frogs with the soil thus reducing water exchange. In very moist soil, a cocoon could limit an influx of water which may be harmful to arid-land anurans (Schmid, 1965). On the other hand, if the soil dries sufficiently to pull moisture out of a frog by virtue of a high soil moisture tension, a cocoon may effectively break capillary contact between the soil and the frog's skin. 56 Aust. Zool. 18(2), 1974.
Size: 2091px × 1195px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1914
