Italian crested newt genes reach Germany

In the 1970s Jozef F. Schmidtler noticed that crested newts in the Berchtesgadener Land, in the extreme southeast of Germany, show morphological characteristics of the Italian crested newt (Triturus carnifex). A particular striking feature was the bright yellow stripe along the back of some juveniles. While this stripe is typical for the Italian crested newt, it is not usually found in the crested newt species that is widely distributed throughout Germany: the northern crested newt (T. cristatus). Schmidtler published his findings in the journal Salamandra.

The yellow stripe that is observed to various extent in juvenile newts (left) is typical of the Italian crested newt. The throat and belly pattern of adult newts is reminiscent of this species as well.

In a new paper also published in Salamandra we employ a genetic toolkit that was originally designed to screen for ‘genetic pollution’ from the Italian into the northern crested newt. For some reason the Italian crested newt has repeatedly been introduced inside the range of the northern crested newt. Hybridization between the two species poses a complicated conservation concern. The genetic toolkit should be able to pick up ‘Italian alleles’ in the natural hybrid zone just as well. Our results are obvious: alleles of the Italian crested newt are indeed present in the Berchtesgadener Land. In other words, the natural hybrid zone between the northern and Italian crested newts just reaches Germany.

Ancestry is the fraction of Italian crested newt alleles and heterozygosity the fraction of genes for which both an Italian and northern crested newt allele are observed. Therefore, only the bottom left corner of the triangle above would represent a pure northern crested newt; any deviation means Italian alleles are present.

Reference: Fahrbach, M., de Visser, M., Wielstra, B. (2021). The hybrid zone between the Italian and Northern crested newts (Triturus carnifex and T. cristatus) reaches Germany. Salamandra 57(1): 428-434.

About Ben Wielstra

I am a biologist interested in the interaction among closely species, both ecologically and genetically, during the course of their evolution. In my studies I'm employing the newt genus Triturus.
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