Vipera walser

Superregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Lepidosauromorpha
Superordo: Lepidosauria
Ordo: Squamata
Subordo: Serpentes
Infraordo: Caenophidia
Superfamilia: Viperoidea

Familia: Viperidae
Subfamilia: Viperinae
Genus: Vipera
Species: Vipera walser
Name

Vipera walser Ghielmi, Menegon, Marsden, Laddaga & Ursenbacher, 2016: 164

Holotype: MSNG 34485, adult ♀, collected by A. Rosazza in the summer of 1930.
Type locality: “San Giovanni d’Andorno, strada per Oropa at 1,300 m a.s.l. in the Alps north of town of Biella, a subrange of the Pennine Alps, Northwestern Italy”.

References
Primary references

Ghielmi, S., Menegon, M., Marsden, S.J., Laddaga, L. & Ursenbacher, S. 2016. A new vertebrate for Europe: the discovery of a range-restricted relict viper in the western Italian Alps. Journal of Zoological Systematics and Evolutionary Research 54(3): 161–173. DOI: 10.1111/jzs.12138 Reference page.

Links

Uetz, P. & Hallermann, J. 2022. Vipera walser. The Reptile Database. Accessed on 23 June 2019.

Vernacular names
Deutsch: Piemont-Viper
italiano: Vipera dei Walser

Vipera walser, the Walser viper or Piedmont viper is a viper endemic to the western Italian Alps. While long considered as an isolated population of Vipera berus, molecular analyses have shown it to be a distinct species related to the Vipera ursinii-complex.[1][2]

Morphology

Morphologically, Vipera walser closely resembles the far more widespread Vipera berus. It differs in having a higher number of cephalic scales and more frequently shows fragmentation of the cephalic large shields. Additionally, most individuals possess 1.5 to 2 rows of subocular scales at both sides of the head, while Vipera berus usually only has a single row. Colouration is highly variable, with some specimens possessing a typical dorsal zigzag pattern, and others with a reduced pattern of horizontal bars.[1] Additionally, melanistic individuals exist.
Geographic range

Vipera walser is limited to a small area north of the Italian town of Biella.[1] The range is divided in a northern population of ±45 km² and a southern population of ±225 km².[3]
Ecology

Vipera walser occurs in open habitats at an altitude of 1300-2300 m in valleys with high precipitation. It is mostly found on gentle south-oriented slopes with low forest cover.[3]
Threats and conservation

Due to its recent description, Vipera walser has not yet been evaluated by IUCN, although the original species description argues that the limited extent of occurrence (<1000 km²) warrants a classification as 'endangered'.[1] Fragmented habitat, decline in agropastoral landuse, culling and collection pose short-term threats, while in the long term climate change may alter the distribution. Additionally, low genetic variability may make the species even more prone to disturbances.[1]
References

Ghielmi, Samuele; Menegon, Michele; Marsden, Stuart J.; Laddaga, Lorenzo; Ursenbacher, Sylvain (2016). "A new vertebrate for Europe: the discovery of a range-restricted relict viper in the western Italian Alps". Journal of Zoological Systematics and Evolutionary Research. 54 (3): 161–173.
Speybroeck, Jeroen (2016). Field guide to the amphibians & reptiles of Britain and Europe. Wouter Beukema, Bobby Bok, Jan Van der Voort, Ilian Velikov. London. ISBN 978-1-4729-3533-5. OCLC 889164386.
Ficetola, Gentile Francesco; Fanelli, Mauro; Garizio, Lorenzo; Falaschi, Mattia; Tenan, Simone; Ghielmi, Samuele; Laddaga, Lorenzo; Menegon, Michele; Delfino, Massimo (2020). "Estimating abundance and habitat suitability in a micro-endemic snake: the Walser viper" (PDF). Acta Herpetologica. 15 (2): 73–85.