Triton

TRITON (Triton). The genus of tritons belongs to the family Salamandridae, order of tailed amphibians (Urodela). Tritons are distinguished by an elongated body, four-toed front and five-toed hind limbs, as well as, as a rule, a laterally compressed tail and a skin crest running along the middle of the back. The latter is more strongly developed in males during the mating period. During this period, tritons live in slowly flowing or stagnant reservoirs with clean water. However, many of them spend a significant part of their lives out of water, so that in the second half of summer they can be found under stones, in bank crevices, and even at a considerable distance from water. They spend the winter by hibernating on land; more rarely, they overwinter in the water. They feed exclusively on animal food, eating insects, mollusks, earthworms, roe and frog tadpoles, and even their own larvae. In captivity, they eagerly eat pieces of raw meat. Young tritons feed chiefly on small crustaceans (Cyclops, Daphnia). Fertilization in tritons occurs without copulation, but is internal. The male deposits packets of semen (spermatophores), the female captures them with the edges of her cloaca, and the spermatozoa penetrate into the cloaca and further into the oviducts. The triton lays fertilized eggs singly, gluing them to various objects (e.g., aquatic plants). Development proceeds with metamorphosis. In the case of obstacles to the completion of metamorphosis, the larvae continue to grow and can even reach sexual maturity (see Neoteny). In water, tritons periodically molt, shedding their skin almost intact and sometimes eating it. Within the USSR, the most widespread species of tritons are Triton cristatus and Triton taeniatus. In Transcaucasia, the Asia Minor triton (Triton vittatus) is found. The triton is an excellent object for laboratory research and is therefore well known to every experimenter. A great deal of work has been done with this subject in studying the phenomenon of regeneration, starting with Spallanzani and Blumenbach, who amputated their legs and tails and excised parts of the eye, obtaining a complete restoration of all the indicated organs. Embryos and larvae of tritons have been widely used to study the questions of embryogenesis by methods of extirpation and transplantation of parts, etc. A number of studies on problems related to the development of sex characteristics, color development, and the like have also been carried out with this subject. V. Zamaraev.