Dear Ruggero,
very intersting variations of Zootoca. The area is interesting in many ways. First of all it would be highly interesting, if the Zootocas are egg layers or livebearing, or maybe both like in Carinthian areas, where they lay eggs in lower elevations and they are viviparous in higher altitudes.
The second story is the occurrence of I. horvathi in this area, which is quite unknown in many areas of Trentino. However, I guess it could be like in Austria, where the records became more and more only recently, because of confusions with P. muralis. Have you ever searched for this species in the region?
Last year I visited the Val dei Mocheni in Trentino and hiked to the Erdemolo lake in June. I only found many many P. muralis on the way up and one Z. longissimus on the way, no Z. vivipara (although I didn't search a lot). I looks also promising for V. berus.
- Lago di Edemolo