Specimens from the northern parts of the species range (alpine form) are generally larger, blacker and tend to have more colourful blotches on their back, which are sometimes pale pink, salmon-pink or orange in colour.
Specimens from the northern parts of the species range (alpine form) are generally larger. This is blacker. Specimens from the northern parts of the species range (alpine form) tend to have more colourful blotches on their back. Their back are sometimes pale pink-pink or orange in colour. This is salmon.