76 Ronald A. Brandon and James E. Huheey 



and Huheey 1981; Brandon et al. 1979a,b; Brodie 1968a,b, 1971, 1977; 

 Brodie and Gibson 1969; Brodie and Howard 1973; Brodie et al. 1974, 

 1979; Dodd et al. 1974; Dodd and Brodie 1976; Hensel and Brodie 1976; 

 Howard and Brodie 1973; Huheey 1960; Hurlbert 1970; Nickerson and 

 Mays 1973; Pough 1971; and Webster 1960). 



Among salamanders, skin toxicity has been examined in detail in 

 Asiatic, European, and North American salamandrids and to a lesser 

 degree among plethodontids. Wakeley et al. (1966) found tetrodotoxin 

 in significant amounts in two species of Cynops, three species of Tari- 

 cha, and one species of Notophthalmus; trace amounts were found in 

 four species of Triturus. Brodie et al. (1974) found a species of Parame- 

 sotriton also to have highly toxic skin, apparently because of tetrodo- 

 toxin. Wakeley et al. (1966) looked for tetrodotoxin in several non- 

 salamandrids — Necturus maculosus, Amphiuma sp., Siren lacertina, 

 Ensatina eschscholtzii, Batrachoseps attenuatus, and Amides lugubris — 

 but found none. The toxic alkaloids of Salamandra salamandra have 

 been studied in great detail (Habermehl 1974), and Triturus cristatus 

 has recently been shown to secrete a toxic protein (Jaussi and Kunz 

 1978). 



Skin extracts containing toxins of high molecular weight have been 

 obtained from Taricha torosa, T. granulosa, Notophthalmus virides- 

 cens, and the plethodontids Pseudotriton ruber and P. montanus 

 (Brandon and Huheey 1981; Huheey and Brandon 1977). They may also 

 be present in some other plethodontids as well (Brandon and Huheey 

 1981; Phisalix 1922; Table 1), but skin extracts of most species of sala- 

 mander remain to be examined. Several other species of plethodontids 

 are demonstrably of reduced palatability to natural and experimental 

 predators (Brodie 1977; Brodie and Howard 1973; Brodie et al. 1979; 

 Dodd and Brodie 1976; Dodd et al. 1974; Huheey 1960). Some species 

 appear to be noxious but not toxic, but to this time skin extracts of all 

 species tested except one of Desmognathus and two of Plethodon have 

 produced toxic symptoms in bioassay animals, and only some species of 

 Desmognathus and some populations of Plethodon jordani seem com- 

 pletely palatable to predators. 



The objective of this report is to describe the effects of crude skin 

 extracts of Necturus lewisi on bioassay mice within the context of sim- 

 ilar tests of extracts from a variety of other species. 



MATERIALS AND METHODS 

 Each of two live specimens of Necturus lewisi was measured (snout- 

 vent length, mm), weighed (nearest mg), then killed by decapitation and 

 pithed. All skin was dissected from the trunk between hind and front 

 limbs, weighed to the nearest mg, and measured to the nearest mm. The 

 skin was immediately minced and frozen in liquid nitrogen and reduced 



