Toxicity in the plethodontid salamanders Pseudotriton ruber and Pseudotriton montanus (Amphibia, Caudata)
Abstract
Pseudotriton ruber and P. montanus possess a proteinaceous skin toxin of mol. wt greater than 200,000. In terms of toxicity and amount present in the skin, pseudotritontoxin is comparable to tetrodotoxin, the other toxin in North American salamanders. The pharmacological action of pseudotritontoxin on mice includes the distinctive symptoms of hyperextension of hind legs and lower back, extreme irritability, severe hypothermia, quiescence, prolonged debility, and coma, with time-to-death of an ld 50 dosage from 12 to 48 hr. Larger doses cause an increase in severity symptoms with convulsions and death occurring at 1 hr or more. In contrast, lethal doses in young chickens cause convulsions and death in a few minutes. The concentration of toxin is greatest in the back skin, being five times that of belly skin, 35 times that of the gut, 18 times that of the liver, and 17 times that of the ovaries. Pseudotritontoxin is the first toxin to be identified in the Plethodontidae, the largest family of salamanders with over 200 known species. It is unusual in being one of the few amphibian poisons of high mol. wt. It also necessitates a re-examination of the mimetic relationships among the red eft, Notophthalmus viridescens, the red salamander, P. ruber, the midland mud salamander, P. montanus diastictus, and the spring salamander, Gyrinophilus porphyriticus. The best interpretation of this mimicry seems to be that of a Müllerian complex with a spectrum of unpalatability among the species.
- Publication:
-
Toxicon
- Pub Date:
- January 1981
- DOI:
- 10.1016/0041-0101(81)90114-8
- Bibcode:
- 1981Txcn...19...25B