Geographic Range
Pseudotriton ruber
, the red salamander, is native in the Nearctic region of the world. The red salamander
is found in the eastern United States ranging as far north as New York southward along
the Appalachian range through Ohio, West Virginia, Virginia, Kentucky, and Tennessee.
Its range extends southward to the Gulf Coast of Louisiana, Alabama, and the western
panhandle of Florida, and can also be located towards the southeast area of the Mississippi
River. The red salamander is absent in Coastal Plain of Virginia, North and South
Carolina, and Georgia.
Habitat
Red salamanders are mainly nocturnal, commonly found in or around slow-moving cold
streams and springs all along the eastern coast from sea level up to 1500 meters.
In adulthood, red salamanders are mostly aquatic and found in deeper springs where
temperatures remain constant in the fall and winter season. In the spring and summer
seasons, they migrate and take shelter under logs, stones, and leaf masses in deciduous
or mixed forest in more terrestrial regions. During rainy nights, they can be spotted
foraging around but usually try to remain hidden in shelter. Female red salamanders
can also be found inhabiting caves to lay their eggs. Juvenile red salamanders typically
stay in the steams for up to 3.5 years before they develop into adults.
- Habitat Regions
- terrestrial
- freshwater
- Terrestrial Biomes
- mountains
- Aquatic Biomes
- rivers and streams
- Other Habitat Features
- caves
Physical Description
Red salamanders are plethodontid salamanders, meaning they lack lungs. Fully-developed adults can be 11 to 18 centimeters in total length. They have a bright orange-red to red dorsum with black spots scattered around their body, with the chin region appearing black. Red salamanders also have a short tail and contain around 16 grooves along their body. Male and female red salamanders are very similar in appearance, with the female being slightly bigger. Older red salamanders can lose their bright red color, changing to a more purplish-brown pigment along with more enlarged spots. The species is also ectothermic, like all other salamanders.
During their larval stage, which can last for 1-3.5 years, can range in growth from 4.5-5 centimeters. Before developing their distinctive bright red color, larval red salamanders are purplish brown on their upper surface and have a yellowish underside with black spots scattered throughout the back, sides, and tail.
Their aposematic color closely resembles the poisonous eastern newt (
Notophthalmus viridescens
). As both species are toxic, predators avoid them. Red salamanders often get confused
with another plethodontid salamander, the mud salamander (
Pseudotriton montanus
). They both have bright red dorsums with black spots throughout their body. To distinguish
the two, red salamanders have a yellow iris and a longer snout than that of the mud
salamander.
- Other Physical Features
- ectothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
Development
During the autumn season when a female red salamander lays her eggs, incubation can last for 2 to 3 months until they are hatched. Once hatched, the hatchlings can average 11 to 14 millimeters snout-vent length (SVL). Depending on the location and water temperatures, average annual growth rates can differ for the species. During the first 6 months, larval populations in coastal areas can be found to grow 1.2-2.0 millimeters per month. At higher elevations (e.g. in Piedmont regions) populations only grow about 1.2 millimeters per month. For the next 2 to 3 years, the total length the red salamander can grow is 10-12 millimeters SVL. The larval period can last from 1.5-3.5 years, depending on the location. In coastal regions, the larval period lasts 18-23 months, whereas in higher elevations the larval period lasts 31-33 months. The longest larval periods have been found in populations in New York, where red salamanders do not reach adulthood for 3.5 years.
Metamorphosis from tadpole to adult occurs between April and November, nut is most
common from April to July. Male red salamanders are considered to be mature when they
reach 53-63 millimeters SVL, and females at 55-68 millimeters SVL.
- Development - Life Cycle
- metamorphosis
Reproduction
During the breeding season red salamanders are polygynandrous, meaning both the male
and female can have multiple mates. Courtship between the male and female red salamander
consist of the male approaching the female first, rubbing his snout along her snout,
cheeks, and underneath her chin. This behavior is common to other plethodontids. The
male then advances his head and body underneath her chin and begins to undulate his
tail. If sexually-receptive, the female will place her chin against the base of the
male's tail and will straddle it. Then the two will engage in this tail-straddle walk
for around 2 minutes until the male releases his spermatophore. Males will normally
deposit at most two spermatophores per night. Once the spermatophore is released,
the male will place his cloaca on the substrate and in a rhythm like fashion contract
his cloaca region while undulating his tail violently. To lead the female over the
spermatophore, the male will raise and arch his tail and flex it from side to side.
The male will continue this until the female moves over the spermatophore and picks
it up. After the female has picked up the sperm packet, the two separate soon after.
- Mating System
- polygynandrous (promiscuous)
Red salamanders are oviparous. They reach sexual maturity between 43 to 48 months after hatching. Adult red salamanders typically breed year-round except for the coldest months (December to Febrauary).
The male drops his spermatophore (sperm packet) externally and the female picks it
up, so that internal fertilization can occur. The female is capable of storing the
sperm for a long period of time before laying her eggs. The female will wait until
conditions are suitable for her to dispatch her eggs, which is typically in the autumn
season. Clutch sizes can range from 29-130 eggs, and egg masses are found on the undersides
of rocks or stones that are in or near water. Incubation periods last from 2 to 3
months, with the eggs hatching from mid-December to mid-February. Once hatched, the
newborn red salamanders are independent.
- Key Reproductive Features
- iteroparous
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
- sperm-storing
The female
Pseudotriton ruber
is the primary parental care provider for the eggs. In preparation for oviposition,
the female will position herself upside down in order to lay her eggs on the underside
of a rock or stone. Once the eggs have been laid, the female provides the protection
from predators and other females until the eggs hatch and then parental care ceases.
- Parental Investment
- female parental care
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
Red salamanders can live approximately 20 years in captivity. Little information is
known about their longevity in the wild.
Behavior
The red salamander is a nocturnal species. Unlike the mainly sedentary, aquatic larval stages, the adults migrate from the streams to terrestrial regions in the spring season. They will then return to the streams in the late summer or fall for breeding. During the winter months, this species may be difficult to locate, suggesting it hibernates.
During the breeding season, males are not aggressive towards each other. Instead,
males may actually court other males. This behavior is thought to be more of a sexual
interference rather than the inability to recognize the opposite sex. The male tries
to cause another male into releasing unnecessary spermatophores.
Home Range
Not much is known about
Pseudotriton ruber
home range. It is not known to be a territorial species, and is often found living
with other salamanders under the same shelter.
Communication and Perception
As with many
plethodontid
salamanders, the male red salamander possess a hedonic gland. The hedonic gland is
usually short, vertically oriented, and in a circular cluster located near the tip
of the chin. This gland plays a role in the courtship of the species by secreting
a sexual stimulant. Red salamanders also possess a naso-labial groove, a shallow,
vertical groove with a slight curvature extending down the mouth. Though not much
is known about the perception of this gland, it is believed that the naso-labial groove
plays a direct role in stimulating the salamander's chemoreception, which is thought
to play a role in reproduction. Plethodontid salamanders also rely on chemical cues
to recognize home ranges, territories, and the sex of potential mates.
- Communication Channels
- chemical
Food Habits
Larval red salamanders are often feeding and foraging throughout the year in aquatic
habitats. In the first 2-3 years of their lives, they mostly consume many aquatic
flies (e.g., larval Chironomid flies), crustaceans, and other aquatic insect and salamander
larvae. They will continue this diet until they develop into adulthood. As adults,
red salamanders will eat many aquatic and terrestrial insects, such as water beetles
(Family Dytiscidae), and earthworms. They will also consume snails, slugs, spiders,
and other small salamanders such as the eastern red-backed salamander
Plethodon cinereus
.
The red salamander uses a tongue protraction ability to capture its prey. Upon seeing
potential prey, the red salamander will extend its tongue, which consists of a tongue
skeleton, by the use of its "m.subarcualis rectus (SAR)"(Deban and Dicke, 1999), the
primary tongue protractor muscle, to capture the insect on its tongue pad, located
at the end of the tongue. After the red salamander has successfully captured its prey,
it retracts its tongue with the use of its "m. rectus cervicis profundus (RCP)"(Deban
and Dicke, 1999) muscle.
- Primary Diet
-
carnivore
- eats terrestrial vertebrates
- insectivore
- eats non-insect arthropods
- molluscivore
- vermivore
- Animal Foods
- amphibians
- insects
- terrestrial non-insect arthropods
- mollusks
- terrestrial worms
Predation
There are little data available about known predators of Pseudotriton ruber . Probable predators may include raccoons ( Procyon lotor ), some woodland birds, the striped skunk ( Mephitis mephitis ), and some species of shrews and snakes. Also, other salamanders have been found to feed on larval red salamanders.
Red salamanders have a bright red color indicating their toxicity. This aposematic
coloration is common to poisonous and noxious species. Many predators avoid these
species after initial contact. When threatened by a predator, the red salamander will
assume a defensive posture of curling its body. This action elevates the rear limbs
and tail while swaying the tail in a wave-like motion from side to side. This occurs
while the red salamander tucks its head underneath the tail.
- Anti-predator Adaptations
- aposematic
Ecosystem Roles
The red salamander plays an ecological role as a predator and prey. They also play host to many protozoans, trematodes, and cestode parasites. Some examples of protozoans found on both larval and adult salamanders include Cryptobia borreli , Cyamoeba bacterifera , Eutrichomastix batrachorum , Hexamastix batrachorum , Heamitus intestinalis , Karotomorpha swezi , Prowazekella longifilis , and Tritrichomonas augusta . Common trematodes found are Allocreadium pseudotritoni , Brachycoelium hospitale , and Gorgoderina bilobata . Only adult red salamanders host the cestode Crepidobothrium cryptobranchi .
The red salamander can be found living in the company of other salamander species
such as the southern
Eurycea cirrigera
or northern two-lined salamander
Eurycea bislineata
and mountain dusky salamander
Desmognathus ochrophaeus
.
- Protozoans ( Cryptobia borreli )
- Protozoans ( Cyamoeba bacterifera )
- Protozoans ( Eutrichomastix batrachorum )
- Protozoans ( Hexamastix batrachorum )
- Protozoans ( Tritrichomonas augusta )
- Protozoans ( Heamitus intestinalis )
- Protozoans ( Prowazekella longifilis
- Protozoans ( Karotomorpha swezi )
- Cestode ( Crepidobothrium cryptobranchi )
- Trematodes ( Allocreadium pseudotritoni )
- Trematodes ( Brachycoelium hospitale )
- Trematodes ( Gorgoderina bilobata )
Economic Importance for Humans: Positive
Although not much is known about how red salamanders benefit humans, this species
is sometimes kept as a pet.
- Positive Impacts
- pet trade
Economic Importance for Humans: Negative
There is no known adverse economic effect of Pseudotrition ruber on humans.
Conservation Status
Red salamanders are listed as endangered in the state of Indiana, a "Species of Special Concern" in Louisiana, and as "Protected" in New Jersey. Despite this, they are typically found in protected areas and are listed as a species of "least concern" by the IUCN Red List.
Because this species lives in woodland areas and clean streams, this species is impacted
by pollution, deforestation, acid drainage from coal mines, and stream siltation.
Other Comments
The defensive posture displayed by red salamanders when provoked has been hypothesized
by a study Howard and Brodie (1972) to be a possible Batesian mimicry of the red eft
stage of eastern newt (
Notophthalmus viridescens
). Critics of this hypothesis state that prey would have relative ease distinguishing
between red salamanders and the red eft because the red salamander is much larger.
Also, like the red eft, red salamanders produce their own toxic protein secretions
called PTTX (pseudotritontoxin) that they use as defense. More critics have stated
that the defensive postures red salamanders use are more similar to related plethondontids
than to newts.
Additional Links
Contributors
Ricky Miller (author), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Emily Clark (editor), Radford University, Cari Mcgregor (editor), Radford University, Jacob Vaught (editor), Radford University.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- terrestrial
-
Living on the ground.
- freshwater
-
mainly lives in water that is not salty.
- mountains
-
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- year-round breeding
-
breeding takes place throughout the year
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- sperm-storing
-
mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.
- female parental care
-
parental care is carried out by females
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- migratory
-
makes seasonal movements between breeding and wintering grounds
- sedentary
-
remains in the same area
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- chemical
-
uses smells or other chemicals to communicate
- aposematic
-
having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- molluscivore
-
eats mollusks, members of Phylum Mollusca
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- metamorphosis
-
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
References
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Lannoo, M. 2005. Amphibian Declines: The Conservation Status of United States Species . California: University of California Press.
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