The smallest of the three native newt species, the Palmate Newt Lissotriton helveticus grows up to nine cm in length with the females slightly larger than the males. The upper surface is olive green/brown and the underside is lemon, or pale lemon-cream, or sometimes a pale orange. Most individuals have some spots on the belly which are smaller than Smooth Newt Lissotriton vulgaris spots. The throat is usually pale pink or cream and almost always spotless. The most strongly coloured and spotted females can be more colourful and spotted than some female Smooth Newts, which can cause confusion.
In the breeding season the aquatic males develop webbed hind feet like a duck, from which the name “palmate” is derived, and these are usually dark in colour. A tail filament, occasionally up to 10 mm long, develops on the blunt-ended tail and this is often nipped short by predators. A tiny crest, scarcely visible, runs along the midline of the male’s back. The dorsal surface has indistinct darker spots, which form two parallel lines on the tail. Males in good condition have an orange flash between the rows of spots on the tail, underlined by a narrow white stripe. Aquatic females lack the tiny crest, tail filament and the dark, webbed hind feet. They have fewer and less distinct spots (Beebee and Griffiths, 2000).
Variations found in our region are mainly in size. Some populations of Palmate Newts have quite small animals, mainly five to seven cm long, and generally darker than usual. Occasional individuals or populations have a sandy yellow-brown dorsal surface instead of the usual brown. Neotonous males have been recorded from Hamsterley Forest. Aquatic males with one webbed hind foot and the other not webbed, or one dark foot and one light foot, are regularly found.
Eggs are laid singly in a folded leaf and are about 3 mm across. These are indistinguishable from Smooth Newt eggs and smaller than Great Crested Newt Triturus cristatus eggs which are about four to five mm across. The aquatic efts, or larvae, are very difficult to distinguish from Smooth Newt efts. Efts have over-wintered in the aquatic phase in recent mild winters. Terrestrial efts are similar to terrestrial adults but smaller and without, or with fewer, smaller dark spots on the underside.
Palmate newts are the most widespread of the newt species in our region, with a predominantly upland bias. They are able to breed in ponds that are slightly more acidic than Smooth Newts can tolerate, though not in the very acidic sphagnum pools. They survive well in woodland ponds, including ponds and ditches in conifer woods. Eastern coastal areas generally lack Palmate Newts, but not always. Their distribution has been expanded by introductions, particularly to garden ponds in the lowland areas, which is blurring their original range.
In Northumberland, Palmate Newts are well distributed in the west of the county but either thinly distributed or not well recorded elsewhere. In Durham, they are also an upland or western species, with strong areas of distribution in the Derwent Valley and Weardale (Durkin, 2010A). They are well distributed in South Tyneside but only as a result of introductions in the 1990s. In the Tees Valley area, Palmate Newts are mainly encountered on the northern fringes of the North York Moors, which probably represents their natural distribution (Rob Scaife, pers. comm., 2010). They are rarely encountered in the Tees Lowlands and their disjunctive distribution there probably indicates that those that are present are the result of introductions. For example Palmate Newts were entirely unrecorded in the borough of Darlington until 2011. Once introduced into garden ponds they seem to be able to establish themselves quite readily.
Upland areas are rarely surveyed for amphibians, so our maps show only a small proportion of the likely number of dots in the western and upland areas.
The Natural England Site of Special Scientific Interest (SSSI) criteria assessment is the same as for Smooth Newts: less than 10 Palmate Newts netted or counted by torchlight is a “Low” population, 10 to 100 is a “Good” population and more than 100 is an “Exceptional” population (Nature Conservancy Council, 1998). A great number of our populations would be “Good” on this basis which perhaps means that this criterion is slightly too generous. In the upland quarry ponds favoured by Palmate Newts they are readily seen by torchlight and counts of over 100 are easily achieved.
Palmate Newts have the most distinctive communities of the three native newt species. Most of the ponds that support Palmate Newts also have Common Frogs Rana temporaria but have neither of the other two newt species (60%). These are the large numbers of fairly acidic moorland and disused quarry ponds in the western, upland areas. Common Toads Bufo bufo are also usually present in the quarry ponds but only rarely in the moorland pools. The second most frequent Palmate community is at lower altitudes, where ponds generally have a more neutral pH, and both Smooth and Palmate Newts are present (30%). The proportions of the two species can vary considerably. Less than 10% of Palmate Newt ponds have all three newt species. Ponds supporting Palmate and Great Crested Newt but not Smooth Newt are very rare.
by John Durkin