Jefferson Salamander
From Freepedia
| Jefferson Salamander | ||||||||||||||
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| Ambystoma jeffersonianum Green, 1827 |
The Jefferson Salamander (Ambystoma jeffersonianum) is a mole salamander native to the north-eastern United States, southern and central Ontario, and south-western Quebec. It was named for Jefferson College in Pennsylvania, which in turn was named for Thomas Jefferson.
It is typically dark gray, brown, or black on its dorsal surface, but a lighter shade on its anterior. Some individuals may also have silver or blue specks on their sides; the area around the vent is usually gray. These salamanders are slender, with a wide nose and distinctive long toes, and range in size from 11 to 18 cm.
Like other mole salamanders, the Jefferson Salamander are burrowers; they have well developed lungs suited for this purpose. Nocturnal by nature, they can be spotted by day during the mating season. Breeding occurs in early spring, after the snow in the area has melted.
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Habitat
The secretive adults tend to hide under stones or logs, or in leaf litter and other underbrush in deciduous forests. Migration to their breeding area is quick, since breeding sites are usually close to the over-wintering burrows. The breeding sites they choose are fishless ponds.
Reproduction
Eggs are laid in small agglomerations attached to submerged twigs or other natural support at the pond's edge. Clutches can contain between 5 to 60 eggs, averaging about 30. The age at which they first breed, and the frequency with which they breed are unknown; estimates are that females will first breed at 22 months, and males at 34 months. Eggs develop rapidly, and may hatch within 15 days. Larvae stay in the pond from two to four months, during which time they grow to between 3 and 8 times their hatching size.
The Jefferson Salamander is known to hybridize with the Blue-spotted Salamander. The offspring are always triploid females, possessing two of each chromosome from the Jefferson Salamander and one of each chromsome from the Blue-spotted Salamander. The presence of these triploid hybrids makes it difficult to identify which species an individual may be, skewing population measures for both species.
The triploid females will mate with either species, but any eggs it lays will not incorporate any genetic information from the sperm. Hence, its offspring will also be a triploid female.
Food
The larvae are carnivorous, typically consuming aquatic invertebrates. An insufficient food supply may result in cannibalistic behaviour. Adults are also carnivorous, eating a variety of small invertebrates.
References
- Environment Canada - Species at Risk: Jefferson Salamander
- Amphibians of Canada: Jefferson salamander
- US Geological Survey - Northern Prairie Wildlife Research Center: Jefferson Salamander
- Ohio History Central: Jefferson Salamander
- Names of the Reptiles and Amphibians of North America
