Siphonops

Abstract: The effect of the skin secretion of the amphibian Siphonops paulensis was investigated by monitoring the changes in conductance of an artificial planar lipid bilayer. Skin secretion was obtained by exposure of the animals to ether-saturated air, and then rinsing the animals with distilled water. Artificial lipid bilayers were obtained by spreading a solution of azolectin over an aperture of a Delrin cup inserted into a cut-away polyvinyl chloride block. In 9 of 12 experiments, the addition of the skin secretion to lipid bilayers displayed voltage-dependent channels with average unitary conductance of 258 ± 41.67 pS, rather than nonspecific changes in bilayer conductance. These channels were not sensitive to 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid or tetraethylammonium ion, but the experimental protocol used does not permit us to specify their characteristics.

Abstract: Relationships among South American caecilians are poorly understood, and many herpetologists have complained of the difficulty of identifying caecilians from that continent. Siphonops is one of the most commonly encountered South American genera, and confusion exists regarding the relationship of that genus to the Brazilian genus Lutkenotyphlus. The problem arises from errors in Taylor's 1968 monograph on caecilians which became apparent upon examination of the holotypes of Lutkenotyphlus brasiliensis (Liitken) and Siphonops confusionis Taylor. In this paper, I show that Lutkenotyphlus Taylor is misdiagnosed but valid and that Siphonops confusionis Taylor is a junior synonym of Lutkenotyphlus brasiliensis (Liitken). NOMENCLATURAL HISTORY.-Liitken (1852) described Siphonops brasiliensis based on a single specimen (ZMUC RO 237) from "Brazil." Dunn (1942) reviewed the early literature and assigned 21 specimens to S. brasiliensis. Taylor (1968) decided that the holotype of S. brasiliensis differed enough from other Siphonops to warrant a new genus which he named Lutkenotyphlus, with S. brasiliensis the generotype and only known species. To date, the holotype is the only reported specimen of L. brasiliensis. Taylor (1968) described a new . 1967b. Evolution of tiger salamanders ( mbystoma tigrinum) on the Grand Canyon species, Siphonops confusionis, to receive the other specimens that had previously been assigned to S. brasiliensis by Dunn (1942) and others. It is ironic that Taylor chose the name confusionis for specmens he believed had been confused with L.