Green salamander
Encyclopedia
Abstract
The Green Salamander (Aneides aneus) is an extremely unique member of the lungless salamanders, Plethodontidae and is the only member of the Aneides genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
that inhabits the Eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
(all other Aneides salamanders are found in the west). Rarely seen in the field, the Green Salamander is an extremely habitat-specific species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
that is seldom found away from its preferred surroundings: moist, shaded rock crevices.
Description and Taxonomy
The Green Salamander is small and notably flat. Aneides aeneus‘ green, lichen-like blotches against a darker dorsum make it the only salamanderSalamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
with green markings. A. aeneus possesses squared toe-tips, large, conspicuous eyes, and a light blue to yellow ventral surface. Adults range from 8–12 cm (3 to 5 in) with 14 to 15 costal grooves.
Currently, aeneus is the only species of the Aneides genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
found in the Eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Some claim that there may be up to four different species of Aneides between the Cumberland Plateau
Cumberland Plateau
The Cumberland Plateau is the southern part of the Appalachian Plateau. It includes much of eastern Kentucky and western West Virginia, part of Tennessee, and a small portion of northern Alabama and northwest Georgia . The terms "Allegheny Plateau" and the "Cumberland Plateau" both refer to the...
and Blue Ridge Escarpment populations, but there has yet to be published molecular data to prove or disbar these claims.
Aneides aneus is the only salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
with green markings. Due also to A. aneus ’ hyper-specific habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
, it is almost unmistakable when found in the field.
Geographic Distribution
Aneides aeneus is known to inhabit both the Alleghenies and Cumberland PlateauCumberland Plateau
The Cumberland Plateau is the southern part of the Appalachian Plateau. It includes much of eastern Kentucky and western West Virginia, part of Tennessee, and a small portion of northern Alabama and northwest Georgia . The terms "Allegheny Plateau" and the "Cumberland Plateau" both refer to the...
, reaching from southwestern 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...
to northern Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
and northeastern Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...
. Isolated populations are known at the Blue Ridge Escarpment at the junction of Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
and South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
. Other disjunct populations are known in central Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
.
Life History
Aneides aeneus is an extreme habitatHabitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
specialist. This species of Aneides is found almost exclusively in an environment following these guild-lines: A. aeneus prefers the crevices of rocks on the sides of cliffs or other outcroppings. Most crevices in which A. aeneus is observed, there is little to no sun light allowed in. This shade may be due to either vegetation outside of the crevice or outcroppings above the crevice. While a number of instances of Aneides aeneus observations in arboreal situations have occurred, most of these instances are in trees either adjacent to rock outcroppings and cliffs, or the specimen in question was located underneath the bark of the tree.
Males are extremely territorial toward other salamanders and would-be predators when disturbed or presented with any manor of threat. Cupp observed aggressive behavior in 45 of 49 instances where a male was placed within an artificial territory of another. Such a high level of aggression
Aggression
In psychology, as well as other social and behavioral sciences, aggression refers to behavior between members of the same species that is intended to cause humiliation, pain, or harm. Ferguson and Beaver defined aggressive behavior as "Behavior which is intended to increase the social dominance of...
is rare in salamanders, and is observed in few other species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, though hardly to the degree as observed in A. aeneus. This aggressive behavior, although in different forms, can also be observed in brooding of the female A. aeneus over her eggs. While the male A. aeneus will attack would-be invaders with such actions as butting, snapping, biting or snout-pressing, females will often snap at objects placed within the breeding crevice or near the eggs she guards.
Breeding Period
- Aneides aeneus has been observed to begin its period of mating and courtshipCourtshipCourtship is the period in a couple's relationship which precedes their engagement and marriage, or establishment of an agreed relationship of a more enduring kind. In courtship, a couple get to know each other and decide if there will be an engagement or other such agreement...
in late May to early June. For Aneides aeneus, the male will enter the breeding crevices and await the arrival of females. Once a male and female meet, the courtship begins. Like some other Plethodon, A. aeneus begins courtship with the female straddling the base of the male’s tail. In this position, and with periodic nudging and encouragement from the male, the two will traverse a small circle within the rock crevice. After some time in this dance, the male will deposit a spermatophore upon the ground and the female, still straddling the base of the male, eventually makes her way to it and “scoops” it up by lateral undulations and slow movements of the base of the tail of the female. - Eggs are laid soon after courtship. The female A. aeneus lies on her back within the rock crevice, her ventral surface pressed against the ceiling. Egg-laying often takes a period of 20 to 30 hours, where the female will apply an adhesive substance to the surface of the rock, followed by a single egg. Clutches of eggs average 15-25 eggs. The female will stay with the eggs, usually wrapping her body around the cluster or at least pressed against it, guarding them for the entirety of development. When presented with a foreign object, be it a wire, stick, or a wandering insect, the female will attack, eating the invader if possible. Female A. aeneus are not known to feed during brooding. Individuals taken from their eggs had their stomachs and small intestines examined and were all found to be completely empty in Gordon’s study in 1971. This guarding period usually lasts 3 months, where the eggs hatch in September.
Dispersal And Aggregation
- Eggs of Aneides aeneus hatch throughout the month of September. Aneides aeneus is a direct developing salamanderSalamanderSalamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
, which means it does not have a larval stage and develops to its adult phase within the egg. Juvenile A. aeneus emerge from the eggs resembling their parents, and will likely leave the crevice in which they were born within 2 months. Follow the hatching of their young, the female A. aeneus no longer shows the hyper-aggressiveness expressed during guarding. In fact, it has been observed that the females will do little to stop the collection or otherwise disturbance of her brood after they have hatched from the eggs. New-born A. aeneus almost always leave the crevice in which they were born and do not return.
Hibernation
- A period in the annual cycle of Aneides aeneus called the pre-hibernation aggregation takes place in which A. aeneus will disperse from the breeding crevices. It is during this period, throughout the month of November, that most specimens of A. aeneus can be observed wandering over and between rock crevices. Following this dispersal, it is thought that A. aeneus ventures deep within the interconnected crevices of the cliffs and rock outcroppings to hibernate. Attempts were made to find A. aeneusunderground, beneath logs, within rotten logs, under rocks and under tree bark, but not a single specimen was produced.
Post-Hibernation Aggregation and Dispersal
- Aneides aeneus emerges from hibernationHibernationHibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
around the month of May. During this period, A. aeneus is observed wandering about the rock crevices and outcroppings, often during light rains at night.
Conservation
Efforts aimed towards the conservation of such a secretive organismOrganism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
are proving complicated. While the fact that Aneides aeneus is such a habitat-specific salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
results in more vulnerability to habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
destruction, the cliffs and outcroppings it has chosen are relatively safe from harm. It has been speculated that A. aeneus inhabited the ancient chestnut
Chestnut
Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...
forest that covered a large percentage of the Great Smoky Mountains National Park
Great Smoky Mountains National Park
Great Smoky Mountains National Park is a United States National Park and UNESCO World Heritage Site that straddles the ridgeline of the Great Smoky Mountains, part of the Blue Ridge Mountains, which are a division of the larger Appalachian Mountain chain. The border between Tennessee and North...
. It is not known whether or not A. aeneus utilized these trees more or less than its currently preferred habitat, but it is certainly a possibility.