Natural variation in the appendicular skeleton of Triturus carnifex (Amphibia: Salamandridae)

Intraspecific variation in the appendicular skeleton of two geographically isolated populations of Triturus carnifex, one from northern Italy (Rosate, Milano) and one from central Italy (Bagnaia, Perugia), has been studied. A total of 1,746 forelimbs and 830 hindlimbs were examined. Forelimb skeletal variability was much greater in the Rosate than the Bagnaia population. Skeletal variants were present in 36.3% and 13.5% of the forelimbs, respectively, or in 54.7% and 22.7% of the netws (P < 0.0001). There were no predominant skeletal variants in Bagnaia, while in the Rosate population, the majority of the variants consisted of fusion of radiale and prepollicis and of phalangeal formula 1-2-3-2. Hindlimb skeletal variability was similar in the two populations and appeared to be much lower than that of the forelimb, with highly significant differences in the frequency of basipodium variants within the Rosate population and in the frequency of acropodium variants in both populations. Skeletal variants were present in about 9% of the hindlimbs, or in about 12% of the newts from either population. At present, no conclusion can be drawn about the mechanisms, genetic and/or epigenetic, underlying the skeletal variability observed in the Triturus carnifex from northern and central Italy. © 1996 Wiley-Liss, Inc.