Genetic study splits Europe's Alpine newt into five species, one new to science

What was long treated as a single species, the Alpine newt, is in fact a complex of five cryptic species that look almost the same but differ clearly in their DNA. Biologists at Leiden University and Naturalis report that one of them is new to science and have named it Mesotriton similis, with the proposed English name Vlasina Alpine newt. The description appears in the taxonomic journal Zootaxa.

A hidden complex across Europe

Alpine newts from different parts of Europe are hard to tell apart by eye, even for specialists. The Leiden team found that the genetic differences between populations are considerable, and that they fall into five distinct lineages that merit species status. Such groups are known as cryptic species: lineages that have diverged genetically while keeping a near-identical outward appearance.

Three of the five species occur in the Netherlands. Besides the native animals, newts from the Balkans and from Italy have been introduced there, so a single country now hosts several members of the complex.

The Vlasina newt

The newly named species comes from the Vlasina Plateau, on the border between Serbia and Bulgaria. Its name, similis, means "similar" in Latin, a nod to how closely it resembles its relatives. According to Ben Wielstra of Naturalis and Leiden University, its genetic distance from the original Dutch newts is at least as large as that between a human and a chimpanzee. That comparison reflects DNA divergence, not any difference in appearance.

The divergence also appears to have biological consequences. Wielstra notes that matings between the new species and other Alpine newt species produce offspring with a much lower chance of survival. Reduced hybrid viability is a classic sign that lineages have become reproductively separated, which supports treating them as separate species rather than regional variants.

Conservation implications

The Vlasina newt is the rarest Alpine newt in Europe. Wielstra and his Serbian co-authors write that its small range and small population leave it highly vulnerable to pollution, habitat degradation and the introduction of fish. Fish introductions are a familiar threat to amphibians that breed in small water bodies, since fish prey on eggs and larvae.

The finding illustrates a wider point for conservation science. A species that appears widespread and secure may, once split, comprise several lineages with much smaller ranges. Protection status and management plans are usually tied to species boundaries, so taxonomic revisions of this kind can change which populations are judged to be at risk.

Open questions

The authors acknowledge that the name may yet change. Amphibian specialists disagree about whether the group should be placed in the genus Mesotriton or in Ichthyosaura, and the authors state that this question has not been settled. The species epithet is unaffected by that debate, but the full name could be revised if the community reaches a different consensus.

The source report does not give the names or ranges of the other four species, the number of animals or sites sampled, or the genetic methods used. Those details will be in the Zootaxa paper (Wielstra et al., 2026, DOI: 10.11646/zootaxa.5897.4.8). Further work would be needed to map where the five lineages meet, whether introduced animals in the Netherlands are interbreeding with native ones, and what the new species' real population size and conservation status are.

Source: Europe's look-alike Alpine newts turn out to be five distinct species (Phys.org, 13 November 2026).

Image: AI-generated illustration.