Palmate Newt
Lissotriton helveticus (Razournowsky, 1789)

Family: Salamandridae - Old World Salamanders

Order: Caudata - Salamanders

Class: Amphibia

Phylum: Chordata - Vertebrates

Kingdom: Animalia

Red List status: Least Concern

Palmate newt, gravid female. Note the dark dorsolateral line on this specimen.
Male palmate newt. Buckinghamshire, UK.
Adult length: 75-100 mm, generally below 90 mm
RANGE

Western Europe, from western Czech Republic east to Portugal. In the United Kingdom it occurs throughout Britain, which marks the northern extent of its range. It is absent from Ireland. Mainland populations in northern Spain and Portugal are scattered.

            Range            Description            Habitat            Behaviour            Biology            Taxonomy            Status            References

DESCRIPTION

 

Adult: A 'typical' newt, with relatively short hindlimbs and well-developed tail fins that end in a blunt tip. The tail is shorter than the snout-vent length. The upper body is light or dark brown or olive, typically with green or brown speckling. A dark dorsolateral line may be present in females. The tail has two rows of prominent dark spots, one towards the top and the other at the base, and inbetween the tail is yellow or orange. The hind feet are olive brown to black. There is a paler ventral surface, with a flush orange or straw-yellow running down the midline of the belly, which is lightly spotted in males and either with

                                                                   fewer spots or unspotted in females. The throat is white or pinkish, and is unspotted.  A dark stripe passes from the snout through the eye, which has a black and gold iris. Three grooves are present on the top of the head, which is rather short and rounded in appearance. There is a short ridge running along the back in males, and ridges at either edge of the dorsum in both sexes, giving the newt a rather square appearance.

 

Female underside. Note the absence of spots on the throat.

 

In breeding condition, male palmate newts become highly distinctive, developing obvious webbing between the digits of the hind feet and a 5 mm long black tail filament extending from the trunctated end of the fins (outside this breeding season, this is noticeable only as a small dark spot at the tip of the tail). Male palmate newts do not develop a prominent crest, but a low crest develops on both the head and tail which has smoother, less undulating edges than that of the smooth newt.

 

Male palmate newt in breeding condition and, right, close-up of the hind foot.

 

 

Larvae: Newt larvae can be recognised by the feathery gills they develop, and by the development of the forelimbs earlier than the hindlimbs in development (the reverse is true of frog larvae). Newt larvae are translucent brown in colour, and may be lightly speckled with black.

 

Eggs: Eggs are laid singly, characteristically in the leaves of aquatic plants which the mother folds over to wrap the egg in a distinctive parcel. The eggs themselves are cream in colour and measure around 1.5 mm in diameter.

 

Similar species: The palmate newt is similar in size, colouration and patterning to the smooth newt (Lissotriton vulgaris). It can most reliably be distinguished from this species by the fact that the smooth newt almost invariably has a spotted throat, while the palmate never does. Typically, female palmate newts have a paler, straw-coloured belly, but this is not universal. Two small tubercles are present on the hind feet of female palmate newts, but not smooth newts. Males in breeding condition can readily be distinguished by the near-absence of a crest in the palmate newt, its possession of a tail filament extending beyond the blunt tips of the tail fins, and by the characteristic webbing that develops between the hind toes of male palmates. Larvae of the two species are indistinguishable. The smooth newt also possesses a hollow between the nostril and the eye that is absent in the palmate.

Male palmate newt in an aquarium set-up. Note the black, webbed hindfeet and tail filament.

 

 

The Italian newt has a throat that is darker than the belly (that of the palmate is paler), is smaller and lighter in colour, and males in breeding condition can be easily distinguished by their lack of webbing or a tail filament. The alpine and Montandon's newts both have bellies that are entirely yellow or red (rather than just the midline). Alpine and Italian newts have only a single groove on the top of the head. Montandon's and Italian newts lack stripes on the side of the head.

 

Confusion is less likely with the great crested newt (Triturus cristatus), which is larger (up to twice as long in some cases), darker and less distinctly patterned. Male great crested newts in breeding condition have a tall, jagged crest that has a 'toothed' appearance. Great crested newt larvae are larger, possess prominent black blotches on the body and tail, and a tail filament.

 

 

HABITAT

 

Varied, being found in hills, mountains and, in lowland areas, grasslands, heaths, deciduous woodland, marshes and brackish coastal pools. This is a disturbance-tolerant species that may colonise garden ponds, although generally more rarely than the smooth newt.

 

Reproductive habitat: Slow-flowing or still waters, often temporary waterbodies such as puddles or ditches. In contrast to the smooth newt, the palmate newt typically colonises ponds with a lower pH (more acidic), often with more shade and clearer water.

 

Elevation: 0 - 2,400 m.

 

 

BEHAVIOUR

 

A nocturnal species that may be fully aquatic at higher elevations, but which in lowland areas is principally terrestrial outside the breeding season. Animals typically emerge to feed at dusk, actively hunting either on land or in the water. Animals aestivate to survive hot, dry periods, and generally overwinter in a dormant state sheltering in animal burrows, beneath leaf litter or in shelter sites.

 

Courtship and reproductive behaviour: Although males display in the water (sometimes during the day), mating itself takes place on land, with a male trailing a female and touching her flanks before depositing a packet of sperm on the ground, which the female collects by placing her cloaca over it. When eggs are laid, females use their hind legs to wrap each individually-deposited egg in a curled leaf.

 

Diet: Palmate newts are opportunistic predators that will take most terrestrial invertebrates. Occasionally larger animals may take juvenile slow worms or other small vertebrates. When adults return to the water during the breeding season, they feed largely on frog and newt eggs and larvae (potentially including their own), small crustaceans and insect larvae. In contrast to great crested newts (Triturus cristatus), palmate newts often feed in midwater.

 

 

BIOLOGY

 

Life cycle: Eggs are laid between March and April. Larvae metamorphose fully after about four months. Metamorphs, about 30 mm long, leave the water at this stage, and remain on land until reproductively mature in the following breeding season.

 

Lifespan: Up to 19 years in captivity.

 

 

TAXONOMY

 

Two morphologically distinct subspecies are recognised. Lissotriton helveticus alonsoi is known from the Iberian Peninsula, and are characterised by smaller size and less complete webbing in breeding males compared with the typical form. L. h. punctillatus is known only from one population in Pozo Negro in Spain; these animals are larger than the typical form and with small dark spots.

 

 

STATUS

 

The palmate newt is covered under Appendix III (Protected Fauna) of the Bern Convention on the Conservation of European Wildlife and Natural Habitats 1979, and also benefits from protected status under national legislation in several states within its range.

 

 

REFERENCES

 

Arnold, N. and Ovenden, D. (2004) Collins Field Guide: Reptiles and Amphibians of Britain and Europe HarperCollins, London: 288pp

Arntzen, J.W., Beebee, T., Jehle, R., Denoël, M., Schmidt, B., Bosch, J., Miaud, C., Tejedo, M., Lizana, M., Martínez-Solano, I., Salvador, A.,  García-París, M., Gil, E.R., Sa-Sousa, P., Gen, P. (2006). Lissotriton helveticus. In: IUCN 2008. IUCN 2008 Red List - Lissotriton helveticus.

Wareham, D.C. (2008) The Reptiles and Amphibians of Dorset British Herpetological Society: 120pp

Male Lissotriton helveticus. Buckinghamshire, UK. Note the grooves on the head, the black-and-gold colouration of the iris, the dark streak through the eye and the lack of a hollow between the eye and the nostril.