Description
A medium-sized salamander. Males up to 85, females up to 95mm total length. Tail length slightly shorter than snout-vent length. Superficially similar to Triturus vulgaris or T. boscai. Glandular ridges alongside the back give the male newts a square-backed appearance. Breeding males have a low, smooth crest along the back that continues into a higher crest on the tail. They also posses a thin filament at the end of the tail and black webbing on the hind feet. These characteristics become less distinct, or can even disappear during the terrestrial stage. Males have a more swollen and darker cloaca than females, and this sexual dimorphism persists in the terrestrial phase. The base color of both sexes is olive-green or brown. A dark line runs from the nares, through the eyes, across the head. This line is bordered ventrally on the cheeks by a bright area, which can be spotted in males. Males show an orange streak centrally along the tail. The lower row of the tail can show a blue area. All males and some females have a dark spotting on the back. Both sexes have a yellow or pale orange belly that can sometimes show some spotting. The throat is never spotted, and this characteristic can be used to distinguish this species from the largely sympatric T. vulgaris.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Belgium, Czech Republic, France, Germany, Luxembourg, Netherlands, Portugal, Spain, Switzerland, United Kingdom

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (1430 records).

This newt has a subatlantic distribution. Its range is restricted to western Europe: from Scotland to the northern part of the Iberian Peninsula; eastwards to the Elbe river in Germany and western Czechoslovakia, and in the lower and middle altitude ranges of the Alps in Switzerland. Differentiation to subspecies level may have taken place during Pleistocene glaciations. The species is common in most of its range due to its wide ecological amplitude. It occurs mainly in lowland marshes, forests, pasture or agricultural land, where all types of standing water are suitable for reproduction. On the northern border of its range, as in The Netherlands and Belgium where the species is rare, its ecological amplitude is narrower, and it is more often found in oligotrophic and slightly acid conditions. On the eastern border of its range, in Switzerland and southern Germany, the species is abundant in forested margins of rivers. Isolated populations occur in the southern part of the range. The glacial distribution was centered in southern France and/or northern Spain. During the postglacial northern expansion the species succeeded in reaching Britain before the island became isolated from the continent. Today, T. helveticus is sympatric over most of its range with T. vulgaris, the phylogenetically most closely related species, the postglacial distribution of which was centered in Eastern Europe. Both species replace each other mutually in the sympatric zone on a macro-scale. However, no effects of competition have been found on a micro-scale; in habitat, food or time resources. An adult hybrid of both species was found once in the wild. The altitudinal distribution ranges fron sea level up to 1455m in the Alps and to about 2200m in Spain. The species is most common between 500 and 1500m (Gasc 1997).

Life History, Abundance, Activity, and Special Behaviors
The reproductive period in Middle- and Western Europe extends from the middle of February until May. The reproductive period on the Iberian Peninsula can occur from January until August, depending on the altitude. The courtship takes place in water, and is superficially like that of the smooth newt, T. vulgaris. A single female can produce 290-440 eggs over one season. Each egg is individually attached to water plants. The eggs are 1.3-1.8mm in diameter, and resemble the eggs of T. vulgaris. The larvae hatch after an embryonal development of 8-14 days at a length of 8-14mm. Metamorphosis can occur after six weeks in the middle European part of the distribution. The larvae often over winter in the water and metamorphose the next year in other parts of its distribution. Neoteny is also known to occur in this species. Sexual maturity is reached in the second year. Longevity is recorded at up to 12 years. Adults hibernate in the more northern parts of the distribution, either on land, or more rarely, in water. On the Iberian Peninsula, however, activity can be year-round. In the reproductive period, the animals are active during the day as well as the night. Outside this period, activity is restricted to rainy or humid nights. T. helveticus feeds mostly on small crustaceans and Plecoptera-larvae The larvae feed on planktonic animals and Daphnia. They are also known to display cannibalistic tendencies (Noellert and Noellert 1992).

Trends and Threats
T. helveticus is protected by law in all countries where it occurs. Its status is thought to be endangered in the Netherlands, Belgium and Luxembourg and vulnerable in Germany. In the remaining countries, the species is more or less common, or at least, not endangered. An exception is made for the isolated populations in Iberia, e.g. the subspecies T. h. sequerai, which is supposed to be seriously threatened (Gasc 1997). Noellert and Noellert (1992) also list forestry, road construction and the introduction of trout as a threat to this species.

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Drainage of habitat
Habitat fragmentation
Predators (natural or introduced)
Introduced competitors

Comments
Although in some regards T. helveticus appears to be competitively inferior to its closest relative T. vulgaris, the species fares well in acidic pond environments. Thus, a decline in quality of ponds in England has led to an increase in the abundance of T. helveticus in some areas. (John W. Wilkinson & John Buckley, FrogLog, 2012).

References

Gasc, J.-P. (1997). Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica, Bonn, Germany.

Griffiths, R.A. (1996). Newts and Salamanders of Europe. T. and A. D. Poyser, London.

Nöllert, A. and Nöllert, C. (1992). Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stuttgart.

Stumpel-Rieks, S. E. (1992). Nomina Herpetofaunae Europaeae. AULA-Verlag, Wiesbaden.

Species Account Citation: AmphibiaWeb 2024 Lissotriton helveticus: Palmate newt <https://amphibiaweb.org/species/4297> University of California, Berkeley, CA, USA. Accessed Jan 21, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Jan 2025.

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