Alpine Salamander

Alpine Salamander
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Caudata
Family: Salamandridae
Genus: Salamandra
Species: S. atra
Binomial name
Salamandra atra
Laurenti, 1768

The Alpine Salamander (Salamandra atra) is a shiny black salamander. It is found in the Central, Eastern and Dinaric Alps, at altitudes above 700 meters. The Western Alps are inhabited by a similar species Salamandra lanzai in only one small area. There are no differences in length between sexes (9 to 14 cm) and sex ratio is 1:1.[1] Their life expectancy is at least ten years. Unlike other salamanders whose larvae are developed in water, the Alpine salamander is a fully terrestrial species. Capture-recapture methods suggest that species is very stationary, a 12 meters was the maximal observed distance travelled by one individual during the summer season. 120 individuals per hectare were counted in most suitable areas with >2000 individuals/ha also observed. This suggests that this rather cryptic species is quite abundant.[2]

Contents

Subspecies

Genetic analysis suggests that Salamandra corsica is the closest related species and that black-yellow coloration is an ancestral feature of Alpine salamanders. Proposed colonization from south (Prealps) to Alps was carried out by fully melanistic (derived feature) S. a. atra after the last retreat of the ice sheets.[3]

Reproduction

Mating occurs on land, the male clasping the female at the arms, and the impregnation is internal. S. atra is an ovoviviparous amphibian, giving birth to two live young, or rarely three or four. They may measure as much as 50 mm. at birth, the mother measuring only 120. The uterine eggs are large and numerous, but as a rule only one fully develops in each uterus, the embryo being nourished on the yolk of the other eggs, which more or less dissolve to form a large mass of nutrient matter. The embryo passes through three stages:[4]

  1. still enclosed within the egg and living on its own yolk
  2. free, within the vitelline mass, which is directly swallowed by the mouth
  3. there is no more vitelline mass, but the embryo is possessed of long external gills, which serve for an exchange of nutritive fluid through the maternal uterus, these gills functioning in the same way as the chorionic villi of the mammalian egg.

Generally, at altitudes of 650-1,000 metres, a pregnancy lasts 2 years, and at altitudes of 1,400 to 1,700 metres, the pregnancy lasts 3 years.

References

  1. ^ Luiselli, andreone, Capizzi, Anibaldi. Body size, population structure and fecundity traits of Salamandra atra atra (Amphibia, Urodela, Salamandridae) population from the northeastern Italian Alps. Italian journal of zoology 2001, 68, 125-130
  2. ^ Bonato, Fracasso. Movements, distribution pattern and density in a population of Salamandra atra aurorae (Caudata: Salamandridae). Amphibia-Reptilia 2003, 24, 251-260.
  3. ^ a b Bonato & Steinfartz. Evolution of the melanistic color in the Alpine salamander Salamandra atra as revealed by a new subspecies from the Venetian Prealps. Italian Journal of Zoology 2001, 72, 253-260.
  4. ^  Chisholm, Hugh, ed (1911). "Salamander". Encyclopædia Britannica (11th ed.). Cambridge University Press. 

External links