Smooth newt

Source: Wikipedia, the free encyclopedia.

Smooth newt
Male during land phase

Least Concern  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Salamandridae
Genus: Lissotriton
Species:
L. vulgaris
Binomial name
Lissotriton vulgaris
(Linnaeus, 1758)
Subspecies[2]
  • L. vulgaris ampelensis (Fuhn, 1951)
  • L. vulgaris meridionalis (Boulenger, 1882)
  • L. vulgaris vulgaris (Linnaeus, 1758)
Synonyms

48,[3] including:

  • Lacerta vulgaris Linnaeus, 1758
  • Salamandra exigua Laurenti, 1768
  • Triton palustris Laurenti, 1768
  • Molge punctata Merrem, 1820
  • Triturus vulgaris Dunn, 1918

The smooth newt, European newt, northern smooth newt or common newt (Lissotriton vulgaris) is a species of newt. It is widespread in Europe and parts of Asia, and has been introduced into Australia. Individuals are brown with a spotted underside that ranges in colour from orange to white. They reach an average length of 8–11 cm (3.1–4.3 in); males are larger than females. The newts' skins are dry and velvety when they are living on land, but become smooth when they migrate into the water to breed. Males develop a more vivid colour pattern and a conspicuous skin seam (crest) on their back when breeding.

The smooth newt was originally described by

genus names before the adoption of its current classification as a member of Lissotriton. There are currently three accepted subspecies of smooth newt. Formerly, there were also four subspecies—all with more restricted ranges—that are now classified as separate species, because they have been found to be distinct genetically as well as in appearance: the Caucasian smooth newt, the Greek smooth newt, Kosswig's smooth newt and Schmidtler's smooth newt. Together with these four species and the Carpathian newt, the smooth newt forms what is known as a species complex: some of the species hybridise
with each other.

For most of the year, smooth newts live on land, are mostly

efts
. They reach maturity after two to three years, and the adults live for up to 14 years.

The smooth newt is abundant over much of its range and is classified as a species of

least concern by the International Union for Conservation of Nature (IUCN). It has been negatively affected by habitat destruction and fragmentation and by the introduction of new species of fish. Like other European amphibians, the smooth newt has now been listed as a protected species by the Berne Convention
.

Taxonomy

Swedish naturalist

polyphyletic, containing several unrelated lineages,[6][7][8] and the small-bodied newts, including the smooth newt, were therefore split off as separate genus in 2004 by García-París and colleagues.[9]: 233  They used the name Lissotriton, introduced by the English zoologist Thomas Bell in 1839 with the smooth newt as type species[10]: 132  but then considered a synonym of Triturus.[3] "Lissotriton" is a combination of the Greek λισσός (lissós), meaning "smooth", and the name of Triton, an ancient Greek god of the sea, while the species epithet vulgaris means "common" in Latin.[11]
: 17 

Three

sister species, have collectively been referred to as the "smooth newt species complex".[12]

To distinguish the smooth newt from its close relatives, the English name "northern smooth newt" has been suggested.[12] Other common names that have been used in the literature include: common newt, great water-newt, common water-newt, warty eft, water eft, common smooth newt, small newt, small eft, small evet, and brown eft.[3]

Evolution

Molecular phylogenetic analyses have shown that the smooth newt is distinct from its four close relatives – the Caucasian, Greek, Kosswig's, and Schmidtler's smooth newt – which were formerly considered subspecies (see section Taxonomy above). The relationships within this species complex have not been fully resolved. Within the smooth newt itself, genetic groups do not completely match the currently accepted subspecies (ampelensis, meridionalis, vulgaris), described based on morphology.[2] The five smooth newt species collectively were estimated to have diverged from the Carpathian newt around four to six million years ago.[13][14]

Genetic analyses have also demonstrated ongoing

hybridisation between the two species is frequent;[11]: 26  it has been shown that smooth newt mitochondrial DNA has introgressed into and completely replaced that of the Carpathian newt populations.[15] Partial introgression also occurred from the smooth newt to the Greek smooth newt.[2] These patterns are likely due to the range expansion and secondary contact of species after the Last Glacial Maximum, which they likely survived in refugia mainly in southern and eastern Europe.[15][14][16] The palmate newt (Lissotriton helveticus), although often occurring in the same habitats, almost never hybridises with the smooth newt.[11]: 25  Artificial crosses with even more distant species such as the alpine (Ichthyosaura alpestris) and northern crested (Triturus cristatus) newts were successful in laboratory experiments.[11]
: 29 

Description

Newt held between fingers, exposing its orange–white, black-spotted underside
Throat and belly are spotted. The spots are larger in males (pictured) than in females.
Swimming male newt, with well developed crest and bright colours
During breeding season, males develop vivid colours and a crest.
Detail of male newt showing swollen, dark-coloured cloaca
The cloaca is swollen in breeding males.
Female newt under water, sitting on leaf
Breeding females are drab in colour and have no dorsal crest.

General characteristics

Adult males of the smooth newt reach around 9–11 cm (3.5–4.3 in) head-to-tail length and are thus slightly larger than the females, which reach 8–9.5 cm (3.1–3.7 in). The body weight of adults varies between 0.3–5.2 g (0.011–0.183 oz), and decreases during the breeding season. The head is longer than it is wide, with 2–3 longitudinal grooves on the top, and the elongated snout is blunt in the male and rounded in the female. The skin is velvety and water-repellent on land but smooth during the aquatic phase; it contains mucus and toxin glands and its upper layer is shed off regularly.[11]: 80–93 [5]: 233–234 

Outside the breeding season, both sexes are yellow-brown, brown or olive-brown. The male has dark, round spots, while the female has smaller spots of the same colour, which sometimes form two or more irregular lines along the back. The male has an orange strip on the tail underside, and the throat and belly in males are orange to white with small dark, rounded spots (these are lighter with smaller spots in the female). Size and colour vary with the environment, and the newts tend to be smaller in northern latitudes.

leucistic individuals have been described.[11]: 94 [17]

The smooth newt is

diploid (i.e. it has two copies of each chromosome), with 24 chromosomes in total.[11]
: 107 

Breeding characteristics

During the aquatic breeding season, males develop a skin seam or crest, which runs uninterrupted along the back and the tail. It is 1–1.5 mm (0.039–0.059 in) high at mid-body, but higher along the tail. The tail also has a lower fin, and its end is pointed. The cloaca (the single digestive, urinary and reproductive orifice) of breeding males is swollen, round and dark-coloured. The hindfeet have more or less developed toe flaps, depending on the subspecies. Colours in general are more vivid than during the land phase. The dark spots grow larger, and the crest often has vertical dark and bright bands. There are five to seven longitudinal stripes on the head. The lower edge of the tail is red with a silver-blue flash and black spots. Females only develop low, straight tail fins but no crest or toe flaps, and are more drably coloured.[18]: 26 [5]: 233–234 

Subspecies differ slightly in male secondary characteristics: L. v. ampelensis has strongly developed toe flaps, its tail tapers into a fine thread (but not a distinct filament), and the body is slightly square in cross-section. L. v. meridionalis also has toe flaps and a pointed tail, its crest is smooth-edged, and its body is square-shaped. In the nominate subspecies, L. v. vulgaris, the crest is clearly denticulated, toe flaps are only weakly developed and the body is round.[5]: 234–236 

Larvae

The aquatic

efts (terrestrial juveniles) just after metamorphosis.[11]
: 188–192 

Similar species

The smooth newt resembles the other, less widespread Lissotriton species. It can be confused especially with the closely related "smooth newt complex" species (marked with * in the table below) and the more distant palmate newt, which often occurs in the same area.[12][11]: 25  Females are especially difficult to tell apart, as distinguishing features are mainly observed in the males at breeding season.[11]: 19–41 [5]: 225–235 

Comparison of the smooth newt and related Lissotriton species[11]: 19–41 [5]: 225–235 
Species Distribution Breeding male characteristics Other
Body shape Dorsal crest Toe flaps (hind feet) Tail end
Smooth newt*
L. vulgaris		 widespread from British Isles to Central Asia round to square (depending on subspecies) smooth or denticulated (depending on subspecies) weakly to well developed (depending on subspecies) pointed to elongated, no filament
Bosca's newt
L. boscai		 West
Iberian peninsula
 slightly square none none short filament belly with some dark spots, especially at sides
Carpathian newt*
L. montandoni
Carpathians
 square very low, smooth-edged weakly developed blunt, with filament belly unspotted
Caucasian smooth newt*
L. lantzi		 Caucasus slightly square high (less than 1 mm (0.039 in) at mid-body), denticulated (almost spine-shaped) moderately developed pointed, but no filament
Greek smooth newt*
L. graecus		 Southern Balkans square low (less than 1 mm (0.039 in) at mid-body), smooth-edged well developed long filament lower tail fin unspotted
Italian newt
L. italicus		 Southern Italy slightly square none none pointed, no filament very small, 4.5–7.5 cm (1.8–3.0 in); throat with few or no spots; golden-yellow patch behind eyes in both sexes
Kosswig's smooth newt*
L. kosswigi		 Northern Anatolia square low (less than 1 mm (0.039 in) at mid-body) but higher at tail base strongly developed long filament
Palmate newt
L. helveticus		 Western Europe square low, smooth-edged strongly developed long filament (both sexes) throat unspotted
Schmidtler's smooth newt*
L. schmidtleri		 Anatolia and eastern Balkans slightly square high (more than 2 mm (0.079 in) at mid-body), denticulated weakly developed elongated, no filament very small, 5–7 cm (2.0–2.8 in)

Distribution

Native range

The smooth newt has been described as "the most ubiquitous and widely distributed newt of the Old World".

Danube delta of northern Romania, and L. v. meridionalis in the northern half of Italy, southern Switzerland, Slovenia and Croatia.[5]
: 234–235 

In the

Carpathians, the smooth newt generally prefers lower elevations than the Carpathian newt. In the Balkans, the precise contact zones with the Greek smooth newt and Schmidtler's smooth newt are not yet clear.[12] In central Italy, where the range of the smooth newt subspecies L. v. meridionalis overlaps with that of the Italian newt (L. italicus), it was found that the latter prefers a warmer and drier climate.[20]

Introduced range

The nominate subspecies, L. v. vulgaris, has been

pet trade until 1997, when it was declared a "controlled pest animal" because of the risk of introduction. The first record in the wild was made near Melbourne in 2011, and larvae were later found, indicating successful reproduction. Negative impacts on the native fauna are feared, including predation on and competition with native frogs and freshwater invertebrates, toxicity, and disease spread. The smooth newt could spread further in south-eastern Australia, where wide areas have a suitable climate.[21]

Within Europe, the subspecies L. v. meridionalis was introduced north of the Alps near Geneva, where it hybridises with the native L. v. vulgaris.[22]

Habitat and ecology

Sunny, water-filled ditch at the edge of a forest
Sun-exposed, stagnant, shallow water bodies with abundant vegetation but without fish, such as this ditch, are typical breeding sites.

Mainly a lowland species, the smooth newt is only exceptionally found above 1,000 m (3,300 ft).[11]: 78–80  This species shows a wide habitat breadth, as it's able to thrive in a wide array of terrestrial and aquatic environments. On land, it occurs in wooded areas (dense conifer woods are avoided) but also in more open areas such as damp meadows, field edges, parks and gardens. It can also tolerate human disturbance and urban environments. The newts hide under structures such as logs or stones or in small mammal burrows.[11]: 120–134 [19][5]: 238  Smooth newts may also climb vegetation, although the exact function of this is not currently known.[23]

Freshwater breeding sites are typically sun-exposed, free from fish, stagnant, water-filled permanently or for at least three months of the year, close to similar water bodies, and have shallow areas with abundant water plants. They can range from small puddles to larger

brackish water.[11]: 121–129  They often share breeding sites with other amphibians, including other newts; in northern France, ponds with five newt species – smooth, palmate, alpine, northern crested and marbled (T. marmoratus) newt – have been described.[11]
: 151–152 

Lifecycle and behaviour

Smooth newts live on land during most of the year and are mainly

efts turn into mature adults at two to three years, and the newts can reach an age of 6–14 years in the wild.[5]: 238  The newts recognise familiar territory using smell and visual cues, but could not orient themselves in experiments when they were transported far away from the home range.[25]

Reproduction

External videos
video icon The life cycle of the newt, British Council, 1942. Educational film on the smooth newt (10:08 min).
Newt larva with feathery gills in side view
Well-developed larva shortly before metamorphosis
efts
) after the transition to land

Migration to the breeding sites occurs as soon as February, but in the northern parts of the range and at higher altitudes, it may not start before summer. After entering the water, the breeding characters, especially the male's crest, take a few weeks to develop.[5]: 238 

Mating involves an intricate

pheromones towards her. In the final phase, he moves away from her, the tail quivering. If she is still interested, she will follow him and touch his cloaca with her snout, whereupon he deposits a packet of sperm (a spermatophore). He then guides her over the spermatophore so she picks it up with her cloaca. Males often try to lead females away from displaying competitors.[5]
: 238–240 

Eggs are fertilised internally, and progeny of one female usually has multiple fathers. Females tend to mate preferentially with unrelated males, probably to avoid inbreeding depression.[26]

Females lay 100–500 eggs, usually folding them into waterplants. The eggs are 1.3–1.7 mm (0.051–0.067 in) in diameter (2.7–4 mm (0.11–0.16 in) with jelly capsule) and light brown to greenish or grey in colour. Larvae typically hatch after 10–20 days, depending on temperature, and metamorphose into terrestrial efts after around three months.[5]: 238–240 

Paedomorphism, where adults stay aquatic and retain their gills and skin seams or only resorb them partially, occurs regularly but only in a small proportion of individuals. It does not appear to be determined genetically but favoured by cold water, a low density of individuals and abundant aquatic prey. Wild paedomorphic individuals often metamorphosed when they were transferred into an aquarium.[11]
: 192–193 

Diet, predators and parasites

Close-up view of snake eating a newt
Grass snake eating a smooth newt

Smooth newts, including the larvae, are unselective carnivores, feeding mainly on diverse invertebrates such as earthworms, snails, slugs, bivalves, spiders, ticks, mites, springtails or insects and insect larvae, or smaller plankton.[27] Cannibalism also occurs, mainly by preying on eggs of its own species. Various predators eat smooth newts, including waterbirds, snakes and frogs, but also larger newts such as the northern crested newt.[5]: 238 

Various pathogens and parasites have been found to infect smooth newts, including

helminths.[32]

Threats and conservation

The smooth newt is common over much of its range.

red lists, e.g. in Switzerland, the Czech Republic, and the Netherlands.[11]: 196  Like all amphibians, it is also listed as protected species in the Berne Convention (Appendix III).[33] Disturbance, capture, killing and trade are prohibited in Ireland under the Wildlife Act 1976,[34] and trade in the UK under the Wildlife and Countryside Act 1981.[35]

Threats to smooth newts are similar to those affecting other amphibians. They include especially the loss of breeding ponds through

quarries left open.[11]: 204–205  The value of artificial water bodies as habitat can be improved when nearby hiding structures like stones or wood are added on land.[36] Garden ponds are readily colonised if they are sun-exposed, have abundant water plants, no fish, and nearby hiding structures.[11]: 206–218  Artificial hibernation sites ("newt hotels") were readily used in a study in Norway, especially by juveniles.[37]

To

phalanges of fingers and toes but these re-grow quickly; a safer and less harmful alternative is recording the individual belly patterns through photography.[11]: 223–224  Researchers have also developed genetic methods based on microsatellite distribution to assess patterns of genetic diversity.[38]

Captivity

Smooth newts can be kept in captivity, but must come from a legal source under the applicable legislation given their protected status (see above). They need a land and water phase, with hibernation for two to three months at 5–10 °C (41–50 °F).[11]: 210–215  The juveniles remain terrestrial and will only return to water at maturity. Individuals have reached ages of 4–8, exceptionally up to 20 years, in captivity.[5]: 240 

References

  1. ^
    doi:10.2305/IUCN.UK.2009.RLTS.T59481A11932252.en
    . Retrieved 1 November 2020.
  2. ^
    PMID 28797693
    .
  3. ^
    doi:10.5531/db.vz.0001. Archived
    from the original on 12 August 2020. Retrieved 18 April 2020.
  4. doi:10.5962/bhl.title.37256. Archived
    from the original on 23 September 2020. Retrieved 20 December 2020.
  5. ^
    ISBN 978-90-04-28562-0
    .
  6. doi:10.1093/sysbio/44.2.125
    .
  7. PMID 16815049
    .
  8. PMID 16969762
    .
  9. ISBN 84-00-08292-3
    .
  10. doi:10.5962/bhl.title.5498
    .
  11. ^
    ISBN 978-3-89432-476-6
    .
  12. ^
    doi:10.1163/15685381-17000128. Archived
    (PDF) from the original on 28 April 2019. Retrieved 19 April 2020.
  13. S2CID 206183624
    .
  14. ^
    S2CID 86108465
    .
  15. ^
    S2CID 7484766
    .
  16. doi:10.21638/11701/spbu03.2016.323
    .
  17. ^ Modesti, Andrea; Aguzzi, Stefano; Manenti, Raoul (2011). "A case of complete albinism in Lissotriton vulgaris meridionalis" (PDF). Herpetology Notes. 4: 395–396. Archived (PDF) from the original on 23 July 2021. Retrieved 13 December 2020.
  18. ^ Beebee, T & Griffiths, R. (2000) The New Naturalist: Amphibians and reptiles – a natural history of the British herpetofauna; Harper Collins Publishers, London.
  19. ^ a b Kuzmin, S. (1999). "AmphibiaWeb – Lissotriton vulgaris". Archived from the original on 19 April 2019. Retrieved 26 April 2020.
  20. PMID 29255477
    .
  21. S2CID 18950725. Archived
    (PDF) from the original on 23 July 2021. Retrieved 10 May 2020.
  22. S2CID 92084541
    .
  23. S2CID 249300071
    .
  24. ^ Kaczmarek, J. M.; Piasecka, M.; Kaczmarski, M. (2018). "Winter activity of the smooth newt Lissotriton vulgaris in Central Europe". The Herpetological Bulletin. 144: 21–22. Archived from the original on 22 October 2021. Retrieved 13 December 2020.
  25. S2CID 83929007
    .
  26. PMID 17638673
    .
  27. ^ "AmphibiaWeb - Lissotriton vulgaris".
  28. PMID 30872735
    .
  29. S2CID 531673
    .
  30. S2CID 27758178
    .
  31. ^ Sinsch, Ulrich; Kaschek, Jacqueline; Wiebe, Jessica. "Heavy metacercariae infestation (Parastrigea robusta) promotes the decline of a smooth newt population (Lissotriton vulgaris)". Salamandra. 45 (3): 210–221. Archived from the original on 22 October 2021. Retrieved 13 December 2020.
  32. S2CID 3709643
    .
  33. ^ "Convention on the Conservation of European Wildlife and Natural Habitats". Bern: Council of Europe. 1979. Archived from the original on 15 July 2015. Retrieved 1 November 2020.
  34. ^ Nelson, B.; Cummins, S.; Fay, L.; et al. (2019). "Checklists of protected and rare species in Ireland" (PDF). Irish Wildlife Manuals. 116. National Parks and Wildlife Service, Department of Culture, Heritage and the Gaeltacht. Archived (PDF) from the original on 25 September 2020. Retrieved 1 November 2020.
  35. ^ "Wildlife and Countryside Act 1981". Article 9, Act of 1981. United Kingdom. Archived 12 February 2019 at the Wayback Machine
  36. S2CID 103494922
    .
  37. doi:10.3390/d10030056
    .
  38. S2CID 46977273
    .

Retrieved from "https://en.wikipedia.org/w/index.php?title=Smooth_newt&oldid=1216813544"