Ambystoma jeffersonianum is a long, slender salamander, ranging from 12.1 to 21 cm in length. Long digits and a wide snout help characterize this species. Bluish flecks often are scattered along the limbs and lower sides of the body, complementing the typical dark-brown or dark gray the species usually exhibits. The ventral stomach is lighter in color, usually gray.
 
This species account was based off the information in the National Audubon Society Field Guide to North American Reptiles and Amphibians (1996) .

This species' range was mapped by Conant and Collins (1991) as encompassing an area in the USA from southeastern New York through Pennsylvania and eastern and southern Ohio to southern Indiana, and southward to south-central Kentucky and northern Virginia, with an extensive area of hybridisation with A. laterale northward of this range to eastern Minnesota, northern Wisconsin, Upper Peninsula of Michigan, southern Ontario, southern Quebec, and eastward to Nova Scotia. However, for most of this range, karyological and electrophoretic data are unavailable, so the precise range of pure jeffersonianum populations is uncertain (Bogart and Klemens 1997). The core of the range of pure A. jeffersonianum populations likely extends from Pennsylvania southwestward to Kentucky. The jeffersonianum genome is widely distributed in eastern North America but exists primarily in hybrids (Bogart and Klemens 1997). Individuals that have solely the A. jeffersonianum genome occur in many hybridised populations. Although Klemens (1993) mapped distinct ranges for A. jeffersonianum and A. laterale in Connecticut and adjacent regions, he included in the range of each species populations that were dominated by the pertinent genome, including hybrids. Data presented by Bogart and Klemens (1997) indicate that the few populations in New England and New York represented by only the A. jeffersonianum genome had sample sizes of only 1-3 individuals, so these actually might have been hybrid populations. Phillips (1991) extended the range of A. jeffersonianum into east central Illinois, based on one juvenile raised from a larva, but since only one specimen was examined (and he did not indicate what identification criteria were used), it is unclear whether or not the population represents pure A. jeffersonianum or a hybrid population. Phillips et al. (1999) indicated the occurrence of both pure A. jeffersonianum and hybridised A. jeffersonianum ("A. platineum") in east central Illinois, and they stated that the hybrids use A. texanum sperm to activate egg development. In northern New Jersey, Nyman et al. (1988) found that triploid hybrids apparently occur wherever A. jeffersonianum is found. In Indiana and Ohio, jeffersonianum genomes exist in hybridised individuals that also contain A. texanum and/or A. tigrinum genomes (Morris 1985, Morris and Brandon 1984,Selander et al. 1993, Selander 1994).

The Jefferson salamander is distributed in patches from southern New England, south and southwest through Indiana, Kentucky, West Virginia, and Virginia (Petranka 1998).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) Conant and Collins (1991) mapped the range as encompassing the area from southeastern New York through Pennsylvania and eastern and southern Ohio to southern Indiana, and southward to southcentral Kentucky and northern Virginia, with an extensive area of hybridization with A. LATERALE northward of this range to eastern Minnesota, northern Wisconsin, Upper Peninsula of Michigan, southern Ontario, southern Quebec, and eastward to Nova Scotia. However, for most of this range, karyological and electrophoretic data are unavailable, so the precise range of pure JEFFERSONIANUM populations is uncertain (Bogart and Klemens 1997). The core of the range of pure A. JEFFERSONIANUM populations likely extends from Pennsylvania southwestward to Kentucky. The JEFFERSONIANUM genome is widely distributed in eastern North America but exists primarily in hybrids (Bogart and Klemens 1997). Individuals that have solely the A. JEFFERSONIANUM genome occur in many hybridized populations.
Although Klemens (1993) mapped distinct ranges for A. JEFFERSONIANUM and A. LATERALE in Connecticut and adjacent regions, he included in the range of each species populations that were dominated by the pertinent genome, including hybrids. Data presented by Bogart and Klemens (1997) indicate that the few populations in New England and New York represented by only the A. JEFFERSONIANUM genome had sample sizes of only 1-3 individuals, so these actually may have been hybrid populations. Phillips (1991) extended the range of A. JEFFERSONIANUM into eastcentral Illinois, based on one juvenile raised from a larva, but since only one specimen was examined (and he did not indicate what identification criteria were used), it is unclear whether the population represents pure A. JEFFERSONIANUM or a hybrid population. Phillips et al. (1999) indicated the occurrence of both pure A. JEFFERSONIANUM and hybridized A. JEFFERSONIANUM ("A. PLATINEUM") in eastcentral Illinois, and they stated that the hybrids use A. TEXANUM sperm to activate egg development. In northern New Jersey, Nyman et al. (1988) found that triploid hybrids apparently occur wherever A. JEFFERSONIANUM is found. In Indiana and Ohio, JEFFERSONIANUM genomes exist in hybridized individuals that also contain A. TEXANUM and/or A. TIGRINUM genomes (Morris 1985, Morris and Brandon 1984,Selander et al. 1993, Selander 1994).

This species is primarily located on the East Coast of the United States, ranging from west New England and southern New York to Virginia and Indiana. Typical habitats consist of swamps and ponds of the deciduous forest regions where A. jeffersonianum may often be found under debris.

The Jefferson salamander can vary from a dark brown, brownish gray or slate gray dorsum and may have light blue speckles scattered along the sides, tail, and occasionally extending onto the back. The speckling is most apparent in younger individuals and may disappear in older adults. The vent region is a grayish color and the ventrum is a pale, sometimes silvery, color. Ambystomid salamanders are generally characterized by prominent costal grooves, short, rounded heads, and stout bodies with robust limbs. The Jefferson salamander, however, has relatively long, slender limbs and toes comparatively. The tail is laterally compressed and extends almost as long as the body. The average adult length ranges from 10.7 to 21 cm, with females being in the upper part of the range, and 12 to 14 costal grooves are present. Breeding males have swollen vents and appear more slender than the egg carrying females. The tail is also longer and more laterally compressed in males. Outside of the breeding season both sexes are darker and less conspicuously marked. Larvae are a yellowish green color with dark blotches on the back. They possess a relatively uncolored caudal fin, and display external gills upon hatching. Older larvae have a mottled greenish gray dorsum and may be marked along the sides with small yellowish spots while the ventrum is pale and generally unmarked (Harding 1997, Petranka 1998).

Length: 21 cm

Syntype for Ambystoma jeffersonianum
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Locality: No Further Locality Data, New York, United States, North America

Syntype for Ambystoma jeffersonianum
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Locality: Cleveland, Cuyahoga, Ohio, United States, North America

Syntype for Ambystoma jeffersonianum
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Locality: Cleveland, Cuyahoga, Ohio, United States, North America

Holotype for Ambystoma jeffersonianum
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Locality: Canonsburg, near Chartier's Creek, Washington, Pennsylvania, United States, North America

Habitat and Ecology

Systems

• Terrestrial
• Freshwater

The Jefferson salamander is restricted to sites containing suitable breeding ponds and shows a strong affinity for upland forests. It prefers relatively undisturbed deciduous woodlands, especially moist, well-drained upland forests (Petranka 1998).

Terrestrial Biomes: forest

Comments: Often in well-shaded deciduous forest; hides in rodent burrows and beneath leaf litter, logs, stumps, and other surface objects; hibernates underground or in rotting logs (Faccio 2003). In caves in some areas (e.g., West Virginia) (Green and Pauley 1987). Eggs are attached to sticks and plant stems in ponds and pools with adjacent forest. Presence of fishes and newts reduces reproductive success. Not found in floodplains, swamps or marshes in New Jersey (Nyman et al. 1988). In central Pennsylvania, embryonic mortality was high in ponds below pH 4.5, though this was affected by the availability of other larval amphibians as prey (Sadinski and Dunson 1992).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

In Kentucky, adults migrated an average of about 250 m from breeding pools to summer range; newly metamorphosed individuals apparently migrated lesser distances (average <100 m in one study) (Douglas and Monroe 1981). In Vermont, 6 radio-tagged individuals migrated 30-205 m (mean 93 m) from their breeding pool; likely a radius of about 175 m around a breeding pool would be needed to encompass 95% of a population (Faccio 2003).

The Jefferson salamander generally feeds on insects and other invertebrate species. The larvae are found to consume small zooplankton after hatching and move on to organisms such as nematodes, aquatic insect larvae, insects, and snails. Larvae may become cannibalistic and feed on small larvae of their own kind and others. Because the adult salamanders spend most of the time, outside of the breeding season, hidden in the ground or under leaf litter their exact feeding habits are not known. It is presumed that they feed on earthworms and other invertebrates found in the soil (Pentranka 1998).

Comments: Adults eat insects, worms, spiders, and other invertebrates, obtained mostly on land. Larvae eat small aquatic invertebrates and smaller amphibian larvae.

Ambystoma tremblayi (Ambystoma laterale, A. maculatum A. tremblayi) preys on:
Daphnia pulex
Gastropoda
Bivalvia
Acilius
Chaoborus

Based on studies in:
USA: Michigan (Lake or pond)

This list may not be complete but is based on published studies.

Ambystoma tremblayi (Ambystoma laterale, A. maculatum A. tremblayi) is prey of:
Ambystoma tigrinum
Batracobdella picta

Based on studies in:
USA: Michigan (Lake or pond)

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Number of occurrences of pure A. jeffersonianum is uncertain, but there are many.

10,000 - 1,000,000 individuals

Comments: Coded value for total adult population size is a guess that pertains only to unhybridized populations. In an extensive survey of New England and New York, Bogart and Klemens (1997) did not find any "sizable" populations. The only populations represented by only the jeffersonianum genome were a few from which only 1-3 specimens were obtained; these may have yielded hybrid individuals if they had been adequately sampled. In Kentucky, where most populations might (but not certainly) represent pure A. jeffersonianum, the species appears to be uncommon, based on the poorly known distribution (Barbour 1971). Similarly, in West Virginia, another area likely represent by pure populations (though this is uncertain), the species is believed to occur statewide but has been documented only from a minority (14) of the state's counties (Green and Pauley 1987), suggesting that A. jeffersonianum is uncommon there.

Comments: Inactive late fall to early winter. Diurnal activity may occur in dark cloudy weather.

The Jefferson salamander is one of the earliest seasonal breeders, migrating to breeding ponds in late winter or early spring, often before the ground and ponds are completely thawed. The first group of males typically precedes the arrival of the first females. Current data suggest that while males breed annually, females may skip one or more years before breeding again. Salamanders are unique among amphibians in practicing internal fertilization. During courtship, the male deposits a spermatophore, a packet of sperm that the female picks up with the lips of her cloaca. The spermatophore is then stored in her spermatheca until she is ready to lay her eggs. While there is no direct cloacal contact, fertilization is internal. Females may begin to lay eggs one to two days after mating. The eggs are 2-2.5 mm in diameter and are encircled by a vitelline membrane and three jelly envelopes. They are generally deposited in small gelatinous clusters and are attached to underwater sticks or vegetation. If the pond should freeze, the eggs are then protected below the surface of the water. The egg masses generally vary in numbers of 20 to 30 eggs per mass but may have anywhere between 1 and 60 eggs per mass. Females will produce a total of 100 to 280 eggs in one breeding season. The length of the incubation varies. In a controlled setting with temperatures around 21oC eggs will hatch in about two weeks, but under more typical, natural conditions, may take up to 14 weeks depending on the time the eggs were laid. The average embryonic survival to hatching is observed to be positively correlated with egg mass size. Hatching success can be very high, however, larvae survival rate is generally very low due to predation. The newly hatched larvae range in length from 1.0 to 1.4 cm. In two to three months the surviving larvae metamorphosied into terrestrial salamanders. If the breeding pond threatens to prematurely dry up, metamorphosis will occur sooner with smaller larvae. The newly metamorphosized individuals range from 4.8 to 7.5 cm and are able to breed in two to three years. The average life span of the Jefferson salamander is six years or longer (Flank 1999, Harding 1997, Petranka 1998).

Eggs are laid February-April (early to mid-March in Ohio). Clutch of a couple hundred eggs is divided among several clusters. Eggs hatch in about 2 weeks (Green and Pauley 1987) or up to 4-6 weeks. Larvae metamorphose during July-September. In a pond in Ohio, hatching rate over four years was 85-90%, and 51,800 to 84,400 larvae hatched (Brodman, 1995, J. Herpetol. 29:111-113). Aggregates when breeding.

Hybrid offspring are the result of gynogenetic or hybridogenetic reproduction (Bogart and Klemens 1997).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 1
Species With Barcodes: 1

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 10
Species With Barcodes: 1

The Jefferson salamander is not currently listed as threatened or endangered. To continue this species' survival relatively undisturbed, woodland habitats near suitable breeding ponds need to be preserved. The increase habitat fragmentation due to roads, leads to the deaths of many salamanders during their spring migration. The Jefferson salamander is also particularly vulnerable to habitat acidification. When pH levels fall too low they become lethal to the larvae and eggs (Harding 1997).

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N2 - Imperiled

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: The Ambystoma jeffersonianum genome is widespread in eastern North America, but it exists mainly in hybrids; the range of pure populations not well documented by apparently is restricted relative to the distribution of the genome.

Intrinsic Vulnerability: Moderately vulnerable

Environmental Specificity: Narrow. Specialist or community with key requirements common.

Comments: Breeding habitat (vernal pools) is moderately to highly specific but common.

Population

Population Trend

Global Short Term Trend: Relatively stable to decline of 30%

Global Long Term Trend: Increase of 10-25% to decline of 50%

During breeding season, which lasts from March to April, adults characteristically migrate to ponds. Cylindrical masses of 10-15 eggs a piece are laid by the female, underwater, and attached to slender twigs. The hatching period will occur 30-45 days later where the larvae are typically 13 mm long. Transformation occurs from the months of July to September where 51 to 71 mm of growth are observed.

Major Threats

Comments: Vulnerable to detrimental alteration of vernal pool breeding sites, especially as a result of residential development. Threats to local populations likely include intensive timber harvesting practices that reduce canopy closure, understory vegetation, uncompacted forest litter, or coarse woody debris (moderately to well-decayed) in areas surrounding breeding sites (deMaynadier and Hunter 1999). Some local populations incur heavy road mortality during migrations to and from breeding sites (Klemens 1993). Increased acid deposition is a potential threat.

Conservation Actions

Global Protection: Many to very many (13 to >40) occurrences appropriately protected and managed

Needs: Conservation goals need to be developed with respect to pure and hybridized populations; should they be assessed separately?

Ecologically, salamanders appear to play important roles in the organization of many terrestrial and aquatic communities. They are increasingly being used as indicators of environmental heath. Salamanders have also proven to be valuable tools in examining various problems in disciplines such as evolution, ecology, animal behavior, physiology, and genetics. Probably most important to the human population is the medical research on salamanders. This includes research to understand the basis for limb and tissue regeneration in vertebrates (salamanders have extraordinary regeneration ability), the study of genetic disorder inheritance, and research exploring the possible therapeutic value of toxic skin secretions in treating human diseases such as cancer (Petranka 1998).

Comments: Ambystoma jeffersonianum and A. laterale comprise a complex that includes pure bisexual diploid populations and populations that may be represented by bisexual diploid individuals, female hybrids with several different combinations of parental chromosomes (including diploids, triploids, tetraploids, and pentaploids), and/or rare male hybrids. Up to at least five different chromosomal combinations have been found at a single site.

In response to the nomenclatural difficulties presented by this complex, an informal system of indicating ploidy and chromosomal makeup has been recommended (Bogart and Klemens 1997). For example, the "LLLJ" designation (or "A. (3) laterale-jeffersonianum") indicates a tetraploid salamander with three sets of laterale chromosomes and one set of jeffersonianum chromosomes. For convenience, all populations including pure laterale (LL) and laterale-dominated genomes (e.g., LLJ) might be included in the species A. laterale (e.g., Klemens 1993).

However, biological complexities confound such a simple treatment. Polyploid hybrid individuals in the complex may produce offspring with diverse chromosomal makeup. For example, an LLJ female can produce offspring that do not have laterale-dominated genomes (e.g., LJJ). And single clutches have been documented with both diploid and triploid embryos. It is even possible for a triploid hybrid to produce pure diploid offspring (e.g., LL or JJ).

Truly intermediate hybrids with equal chromosomal representation (i.e., LJ, LLJJ) are uncommon and are but two of many possible outcomes of hybridization. In New England and New York, hybrids are more common than are the bisexual species, but bisexuals usually (or are presumed to) exist in low numbers in populations composed mostly of hybrids (Bogart and Klemens 1997). Thus, for example, a pond with triploid LLJ should also have at least some LL.

Hybrid populations are maintained by breeding between a hybrid female and a male of one of the diploid bisexual species, and the hybrid offspring are the result of gynogenetic or hybridogenetic reproduction (Bogart and Klemens 1997). In gynogenetic reproduction, male sperm stimulates egg development, but the male genome is not incorporated into the zygote. In hybridogenetic reproduction, the male genome is incorporated, "but upon maturity of the offspring, the paternal genome is eliminated in a meiotic or pre-meiotic event while the rest of the hybrid's genome is passed on to future generations, usually in an altered state" (Bogart and Klemens 1997).

Thus, recent work on hybrid phenomena in these salamanders indicates that the species names "A. platineum" (= LJJ) or "A. tremblayi" (= LLJ) formerly used for the A. jeffersonianum-A. laterale hybrids are inappropriate because LJJ and LLJ are not strictly gynogenetic triploid lineages. Consequently, a recent checklist (Crother et al. 2000) did not recognize either A. platineum or A. tremblayi as valid species.

To accommodate the genetic variation in these salamanders (and the often uncertain genetic composition of particular populations), we have established for this database the following elements: (1) Ambystoma jeffersonianum (JEFFERSON SALAMANDER), used for pure populations only; (2) Ambystoma laterale (BLUE-SPOTTED SALAMANDER), used for pure populations only; (3) Ambystoma HYBRID POP 1 (JEFFERSONIANUM X LATERALE; JEFFERSONIANUM GENOME DOMINATES), used for hybrid populations dominated by the jeffersonianum genome (e.g., populations that include mainly LJJ individuals); this element includes "Ambystoma platineum"; (4) Ambystoma HYBRID POP 2 (JEFFERSONIANUM X LATERALE; LATERALE GENOME DOMINATES), used for hybrid populations dominated by the laterale genome (e.g., populations that include mainly LLJ individuals); this element includes "Ambystoma tremblayi"; (5) AMBYSTOMA POP 3 (JEFFERSONIANUM/LATERALE COMPLEX - UNCERTAIN COMPOSITION), used for populations for which chromosomal representation is unknown. If needed we could establish additional elements for hybrid populations that involve A. laterale, A. texanum, and/or A. tigrinum.

See Kraus (1985), Bogart and Licht (1987), Bogart et al. (1987), Kraus et al. (1991), Lowcock et al. (1991), and Bogart and Klemens (1997) for information on the involvement of A. JEFFERSONIANUM in hybridization with A. TEXANUM, A. TIGRINUM, and/or A. LATERALE. See Lowcock et al. (1987) and Bogart and Klemens (1997) for discussions of nomenclatural treatment of hybrid populations.

See Kraus (1988), Shaffer et al. (1991), and Jones et al. (1993) for phylogenetic analyses of North American Ambystoma.