Jefferson Salamander
Encyclopedia
The Jefferson salamander (Ambystoma jeffersonianum) is a mole salamander native to the northeastern
United States
, southern and central Ontario
, and southwestern Quebec
. It was named after Jefferson College in Pennsylvania
.
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 burrows; 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.
s will first breed at 22 months, and male
s 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.
A unique reproductive tactic for the Bluespotted-Jefferson Salamander Complex
exists in nature. The Jefferson salamander is now known not to breed in the lab with the Blue-spotted Salamander
, which was previously thought to produce 'hybrids', the Silvery Salamander
and Tremblay's Salamander
, between this supposed mating of Jefferson salamander and Blue-spotted salamander. The Silvery salamander and Tremblay's salamander are now known through genetic testing to be polyploidy
females (only 2% of males survive and they are sterile). These most often possess two of each chromosome
from the Jefferson salamander and one of each chromosome from the Blue-spotted salamander, resulting in a LJJ genotype
(also called a Tremblay's Salamander.) This genotype results when these polyploid females mate with a pure Jefferson salamander male, incorporating (often in warmer water conditions) the chromosome from the pure male Jefferson salamander into her egg, usually having an LJ diploid chromosome set or LJJ triploid chromosome set, to produce LJJ or LJJJ offspring, respectively. Often in cooler conditions, the LJ or LJJ female may mate with the Jefferson salamander male and only 'borrow' his spermatozoan to trigger genetic
cloning
of herself, not adding his chromosome (J) to her egg. The same polyploid reproductive strategy occurs for other mole salamander
species. The presence of these polyploids makes it difficult to visually identify which species an individual may be, skewing population measures for both species.
forests during damp conditions. They are usually not found in conifer forests, likely due to the dryness and prickliness of some pine and spruce needles, which may injure amphibians with their thin skins. They are found burrowed underground for most of the year during dry or freezing conditions. They must get below the frost line (about 18 inches) in order to survive winter conditions in northern latitudes. They often burrow in rich sandy soils found in upland deciduous forests or sometimes in older-growth damp hemlock
forests.
Migration to their breeding area is quick, and is usually done during or right after a heavy rainfall. since breeding sites are usually close to the over-wintering burrows. The breeding sites they choose are fishless ponds and vernal pool
s, filled with spring snow meltwater in northern latitudes. Some breeding ponds may be hundreds of yards (meters) away from their forest home in fragmented
landscapes.
Jefferson salamanders are one of the first amphibians to emerge in springtime at the northern edge of their range in southern Ontario
, Canada
where they are seen "snowshoeing" across the still frozen understory of the forest to reach partially melted breeding ponds. Males migrate first with females following shortly thereafter. Jeffersons have small pores on their heads which, when handled, exude a whitish liquid, suggesting that they may leave a scent trail during migration (Jaeger et al. 1993).
s. An insufficient food supply may result in cannibalistic
behaviour. Adults are also carnivorous, eating a variety of small invertebrates.
Northeastern United States
The Northeastern United States is a region of the United States as defined by the United States Census Bureau.-Composition:The region comprises nine states: the New England states of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont; and the Mid-Atlantic states of New...
United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, southern and central Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, and southwestern Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
. It was named after Jefferson College in Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
.
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 burrows; they have well-developed lungs suited for this purpose. Nocturnal
Nocturnal animal
Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "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.
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 femaleFemale
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
s will first breed at 22 months, and male
Male
Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
s 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.
A unique reproductive tactic for the Bluespotted-Jefferson Salamander Complex
Mole salamander
The mole salamanders are a group of salamanders endemic to North America, the only genus in the family Ambystomatidae...
exists in nature. The Jefferson salamander is now known not to breed in the lab with the Blue-spotted Salamander
Blue-spotted Salamander
The Blue-spotted salamander, or Ambystoma laterale, is a mole salamander native to the Great Lakes states and northeastern United States, and parts of Ontario and Quebec in Canada. Their range is known to extend to James Bay to the north, and southeastern Manitoba to the west.-Description:These...
, which was previously thought to produce 'hybrids', the Silvery Salamander
Silvery Salamander
The Silvery Salamander is a member of the Mole salamander genus. It is usually between 5.5 – 7.75 in long and is slender with many small silvery-blue spots on its back and sides. It is brownish gray and the area around its vent is grey...
and Tremblay's Salamander
Tremblay's Salamander
Tremblay's Salamander is a member of the Ambystomidae. Reaching between 3¾ and 6⅜" , the salamander is long and slender with many bluish-white markings. It is dark gray to gray-black and the area around the vent is black. Tremblay's Salamander is a hybrid species of the Jefferson Salamander and...
, between this supposed mating of Jefferson salamander and Blue-spotted salamander. The Silvery salamander and Tremblay's salamander are now known through genetic testing to be polyploidy
Polyploidy
Polyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
females (only 2% of males survive and they are sterile). These most often possess two of each chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
from the Jefferson salamander and one of each chromosome from the Blue-spotted salamander, resulting in a LJJ genotype
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...
(also called a Tremblay's Salamander.) This genotype results when these polyploid females mate with a pure Jefferson salamander male, incorporating (often in warmer water conditions) the chromosome from the pure male Jefferson salamander into her egg, usually having an LJ diploid chromosome set or LJJ triploid chromosome set, to produce LJJ or LJJJ offspring, respectively. Often in cooler conditions, the LJ or LJJ female may mate with the Jefferson salamander male and only 'borrow' his spermatozoan to trigger genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
cloning
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...
of herself, not adding his chromosome (J) to her egg. The same polyploid reproductive strategy occurs for other mole salamander
Mole salamander
The mole salamanders are a group of salamanders endemic to North America, the only genus in the family Ambystomatidae...
species. The presence of these polyploids makes it difficult to visually identify which species an individual may be, skewing population measures for both species.
Habitat
The secretive adults tend to hide under stones or logs, or in leaf litter and other underbrush in deciduousDeciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
forests during damp conditions. They are usually not found in conifer forests, likely due to the dryness and prickliness of some pine and spruce needles, which may injure amphibians with their thin skins. They are found burrowed underground for most of the year during dry or freezing conditions. They must get below the frost line (about 18 inches) in order to survive winter conditions in northern latitudes. They often burrow in rich sandy soils found in upland deciduous forests or sometimes in older-growth damp hemlock
Eastern Hemlock
Tsuga canadensis, also known as eastern or Canadian hemlock, and in the French-speaking regions of Canada as pruche du Canada, is a coniferous tree native to eastern North America. It ranges from northeastern Minnesota eastward through southern Quebec to Nova Scotia, and south in the Appalachian...
forests.
Migration to their breeding area is quick, and is usually done during or right after a heavy rainfall. since breeding sites are usually close to the over-wintering burrows. The breeding sites they choose are fishless ponds and vernal pool
Vernal pool
Vernal pools, also called vernal ponds or ephemeral pools, are temporary pools of water. They are usually devoid of fish, and thus allow the safe development of natal amphibian and insect species...
s, filled with spring snow meltwater in northern latitudes. Some breeding ponds may be hundreds of yards (meters) away from their forest home in fragmented
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
landscapes.
Jefferson salamanders are one of the first amphibians to emerge in springtime at the northern edge of their range in southern Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
where they are seen "snowshoeing" across the still frozen understory of the forest to reach partially melted breeding ponds. Males migrate first with females following shortly thereafter. Jeffersons have small pores on their heads which, when handled, exude a whitish liquid, suggesting that they may leave a scent trail during migration (Jaeger et al. 1993).
Food
The larvae are carnivorous, typically consuming aquatic invertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s. An insufficient food supply may result in cannibalistic
Cannibalism (zoology)
In zoology, cannibalism is the act of one individual of a species consuming all or part of another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded for more than 1500 species...
behaviour. Adults are also carnivorous, eating a variety of small invertebrates.
External links
- Jefferson Salamander (Ambystoma jeffersonianum), Natural Resources Canada