Age, Growth and Longevity of Sympatric Triturus cristatus, T. marmoratus and Their Hybrids (Amphibia, Urodela): A Skeletochronological Comparison

In the ponds of some regions of France, Triturus cristatus and Triturus marmoratus coexist and natural hybrids can be found. In the course of our study examining evolutionary strategies of newts, the method of individual age determination (skeletochronology) was applied. Cross-sections of femurs and phalanges were stained with Ehrlich hematoxylin. Hematoxylinophilic lines considered to be Lines of Arrested Growth (LAG) were observed and carefully counted. Our results on longevity, median age, sexual maturity and growth rate concur with the observations on life span of the two species in allopatric situations. The general morphology of the hybrids, age at sexual maturity and median life span were intermediate between those of the parental species.