''Vipera walser'', the Walser viper or Piedmont viper is a

viper The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, and various other isolated islands. They are venomous and have long (relative to non-vipers), hinged fangs tha ...

endemic to the western Italian Alps. While long considered as an isolated population of ''

Vipera berus ''Vipera berus'', the common European adderMallow D, Ludwig D, Nilson G. (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. . or common European viper,Stidworthy J. (1974). ...

'', molecular analyses have shown it to be a distinct species related to the ''

Vipera ursinii :''Common names: meadow viper, Ursini's viper, Mallow D, Ludwig D, Nilson G (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. . meadow adder,Brown, John Haynes (1973). ''To ...

''-complex.

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. Additionally,

melanistic The term melanism refers to black pigment and is derived from the gr, μελανός. Melanism is the increased development of the dark-colored pigment melanin in the skin or hair. Pseudomelanism, also called abundism, is another variant of pi ...

individuals exist.

Geographic range

''Vipera walser'' is limited to a small area north of the Italian town of

Biella Biella (; pms, Biela; la, Bugella) is a city and ''comune'' in the northern Italian region of Piedmont, the capital of the province of the same name, with a population of 44,324 as of 31 December 2017. It is located about northeast of Turin an ...

. The range is divided in a northern population of ±45 km² and a southern population of ±225 km².

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.

Threats and conservation

Due to its recent description, Vipera walser has not yet been evaluated by

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

, although the original species description argues that the limited extent of occurrence (<1000 km²) warrants a classification as '

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

'. Fragmented habitat, decline in agropastoral landuse, culling and collection pose short-term threats, while in the long term

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

may alter the distribution. Additionally, low

genetic variability Genetic variability is either the presence of, or the generation of, genetic differences. It is defined as "the formation of individuals differing in genotype, or the presence of genotypically different individuals, in contrast to environmentally i ...

may make the species even more prone to disturbances.

References

{{Taxonbar, from=Q25653167 Reptiles described in 2016

walser The Walser people are the speakers of the Walser German dialects, a variety of Highest Alemannic. They inhabit the region of the Alps of Switzerland and Liechtenstein, as well as the fringes of Italy and Austria. The Walser people are named af ...

Reptiles of Europe