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The ocoee salamander (''Desmognathus ocoee'') is a species of
salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...
in the family
Plethodontidae Plethodontidae, or lungless salamanders, are a family of salamanders. With over 500 species, lungless salamanders are by far the largest family of salamanders in terms of their diversity. Most species are native to the Western Hemisphere, from B ...
. This salamander has a variety of colors and patterns, and got its name from Tennessee state wildflower. Its natural
habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
s are
temperate forest A temperate forest is a forest found between the tropical and boreal regions, located in the temperate zone. It is the second largest terrestrial biome, covering 25% of the world's forest area, only behind the boreal forest, which covers about 3 ...
s, rivers, intermittent rivers, freshwater
spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a he ...
s and wet rocks in mountainous areas of the Southeastern United States. It was first described by Nicholls in 1949. They are territorial and feed on small invertebrates. It is widely distributed in the southeastern United States and is listed as "Least Concern" by the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
.


Description

The ocoee salamander (''Desmognathus ocoee'') is a small mountain dusky salamander that exhibits a wide range of colors and patterns. The species got its name from the Tennessee state wildflower and symbol ''
Passiflora incarnata ''Passiflora incarnata'', commonly known as maypop, purple passionflower, true passionflower, wild apricot, and wild passion vine, is a fast-growing Perennial plant, perennial vine with climbing or trailing stems. A member of the passionflower ge ...
'' (passionflower), which is termed "ocoee" in the Cherokee tribe. The
Ocoee River The Toccoa River and Ocoee River are the names in use for a single river that flows northwestward through the southern Appalachian Mountains of the southeastern United States. It is a tributary of the Hiwassee River, which it joins in Polk Co ...
and the Ocoee salamander were thus named after the Cherokee word for passionflower. Some individuals have distinct red, yellow, or orange patches on their legs and cheeks. Populations in central
Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...
, northwestern
Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...
, and northeastern
Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...
usually have a dark brown or black color, and faded larval spots. Compared to other ''
Desmognathus ''Desmognathus'' is a genus of lungless salamanders in the family Plethodontidae known as dusky salamanders. They range throughout the eastern United States as far west as Texas, and north to southeastern Canada. Characteristics Species of th ...
'' species, ''Desmognathus ocoee'' have smaller bodies (around 7–11 cm), shorter and narrower heads, longer limbs, and no
vomerine teeth The vomer (; ) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms t ...
in adult males. Juveniles have pairs of alternating pale spots on their middorsal line. As they move on to adulthood, these spots might fuse.


Habitat and distribution


Habitat

The ocoee salamander is found in two separate populations. The more numerous is in the
Blue Ridge Mountains The Blue Ridge Mountains are a Physiographic regions of the United States, physiographic province of the larger Appalachian Highlands range. The mountain range is located in the Eastern United States and extends 550 miles southwest from southern ...
and at lower levels in the gorges of the rivers Hiwassee, Ocoee,
Tugaloo Tugaloo (''Dugiluyi'' (ᏚᎩᎷᏱ)) was a Cherokee town located on the Tugaloo River, at the mouth of Toccoa Creek. It was south of Toccoa and Travelers Rest State Historic Site in present-day Stephens County, Georgia, United States. Cultu ...
and Tallulah. The less numerous population is in the
Appalachian Plateau The Appalachian Plateau is a series of rugged dissected plateaus located on the western side of the Appalachian Mountains. The Appalachian Mountains are a range that run from Nova Scotia in Canada to Alabama in the United States. The Appalachi ...
in northeastern Alabama. It is found over a greater range of altitudes than other members of the genus ''
Desmognathus ''Desmognathus'' is a genus of lungless salamanders in the family Plethodontidae known as dusky salamanders. They range throughout the eastern United States as far west as Texas, and north to southeastern Canada. Characteristics Species of th ...
''. At lower levels it is an aquatic species but at higher altitudes it is mostly terrestrial. It is found close to fast flowing mountain streams, in seepage areas, on moist forest floors and on wet rocks. In cove valleys in the
Appalachian Mountains The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...
it prefers hardwood forests with trees that are more than eighty-five years old.
Semi-aquatic In biology, being semi-aquatic refers to various macroorganisms that live regularly in both aquatic and terrestrial environments. When referring to animals, the term describes those that actively spend part of their daily time in water (in ...
salamanders like the ocoee contribute considerably to the terrestrial vertebrate biomass. They depend on water for reproduction, but their short larval period allows them to take advantage of wetted habitats such as small streams and wet rock faces. Despite this, they are the most terrestrial of the stream-breeding ''Desmognathus'' salamanders. Under moist conditions, they will leave streambeds and move into the forest. They prefer cove forests of more than 85 years of age, with a significant amount of emergent rocks. These rocks are important for soil moisture retention, and are thus vital for the survival of ''D. ocoee'' eggs during brooding. As vertebrate predators, ''D. ocoee'' are integral to the dynamics of the food webs around their habitat. They can often be found some distance from a water source, usually in the forest at higher elevations. Population densities on wet rock faces are around six adults per meter square. Overall, the population trends for the ocoee salamanders in the
Appalachian Mountains The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...
have not changed significantly in the last twenty years.


Population structure, speciation, and phylogeny


Close relatives

The ocoee salamander has gone through various classifications in the last century. Originally considered as a single species ('' D. ochrophaeus''), populations of ''
Desmognathus ''Desmognathus'' is a genus of lungless salamanders in the family Plethodontidae known as dusky salamanders. They range throughout the eastern United States as far west as Texas, and north to southeastern Canada. Characteristics Species of th ...
'' salamanders across the
Appalachians The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...
are now divided into five distinct species '' D. abditus'', '' D. carolinensis'', ''D. ochrophaeus'', ''D. ocoee'', and '' D. orestes''. These five species do not form a phylogenetic clade and are differently related to one another, but complete reproductive isolation is rarely observed in distantly related ''Desmognathus'', and thus some hybridization between geographically-close lineages occurs. The "gray zone" that contains the potential arguments on species delimitation still exists, but genetic analyses provide enough evidence for the delimitation of these five species.


Genetic population structure

Before the advancement of genetic and molecular techniques, the classification of plethodontids was limited by geographical and morphological differences between individuals and groups. This was not a very accurate method for taxonomy because the color patterns and phenotypic variations among the family of Plethodontids was conserved and the genetic underpinnings of these morphological traits were not well known. In genetic studies in the past few decades, by the use of biochemical markers, it has been shown that this conservatism of morphological traits in many of the salamanders of the family
Plethodontidae Plethodontidae, or lungless salamanders, are a family of salamanders. With over 500 species, lungless salamanders are by far the largest family of salamanders in terms of their diversity. Most species are native to the Western Hemisphere, from B ...
actually sometimes masks complex patterns of genetic differentiation. These genetic studies ultimately allowed for better-defined species delimitation of ''Desmognathus ocoee''.


Territoriality and diet

The ocoee salamander maintains a small
territory A territory is an area of land, sea, or space, belonging or connected to a particular country, person, or animal. In international politics, a territory is usually a geographic area which has not been granted the powers of self-government, ...
when on land, which it defends against other conspecific members. The Ocoee salamanders feed on insects and other small
invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...
s. Potential prey species include flies, ants, wasps, beetles, spiders, mites. Studies suggest that larval ''D. ocoee'' prefer to feed at low elevation rock faces and high elevation woodland habitats over high elevation rock faces. This is likely due to the cooler environment associated with elevated altitudes, which reduces the salamander's general activity levels. The ocoee salamander was used as a study subject to measure the impact of stress on feeding behavior. Stress was induced either by 1) repeated handling, or 2) CORT glucocorticoid hormone administered via a dermal patch. Both stressful conditions led to reduced feeding in females, and reduced activity and body weight in both sexes compared to a control group.


Predators

It is preyed upon by birds, snakes, and even another species of salamander. The ocoee salamander has developed many different anti-predator defenses to use in different situations. When approached by a predator it may remain immobile, but is more likely to flee when it encounters the Spring salamander (''Gyrinophilus'' ''porphyriticus''). The salamanders are also prone to autotomizing the tail to avoid an attack. When attacked by a snake, ocoee salamanders writhe about and try to bite the snake on the head.


Mating


Pheromones

Pheromonal communication is very common in
salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...
s,
newt A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aqua ...
s, and even in some
frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
s and
toad Toad (also known as a hoptoad) is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands. In popular culture (folk taxonomy ...
s.
Pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s are chemosensory stimuli that are used to signal information between individuals of the same species. In vertebrates, there are two types of pheromones. Releasing pheromones are usually peptides and proteins that influence behaviors (such as male-female or male-male interactions) through neural systems that detect and process pheromones. Priming pheromones modify the
endocrine system The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant Organ (biology), organs. In vertebrat ...
or the psychological mood of the individual. Usually, these different types of pheromones exist as a mixture, so they have complex behavioral and psychological effects. Pheromones from other individuals are detected by the
chemosensory A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...
receptors on the vomeronasal organ and main olfactory epithelium. Chemosensory cues such as pheromones play an important role in mating because they bring males and females together in both aquatic and terrestrial environments. These cues can signal a variety of information to others in the surrounding area, including the species, sex, and the reproductive condition of the individual. Once suitable partners have been attracted, these cues can also help determine mate quality.


Courting

Sexually active adults use a variety of tools to court each other before copulation occurs. As is common in the plethodontids, a female is exposed to tactile, chemical, and visual stimuli presented by the male. The females will also signal attraction through chemical cues, reduced tendencies to flee from courting males, and a willingness to engage in tail-straddle walk, which is the phase in courtship where insemination occurs. This course of behaviors from both individuals will lead to successful copulation.


Copulation

Ocoee salamanders do internal fertilization. When a female is ready for mating, the male uses a
spermatophore A spermatophore, from Ancient Greek σπέρμα (''spérma''), meaning "seed", and -φόρος (''-phóros''), meaning "bearing", or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especiall ...
to transfer his sperm to a female. A
spermatophore A spermatophore, from Ancient Greek σπέρμα (''spérma''), meaning "seed", and -φόρος (''-phóros''), meaning "bearing", or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especiall ...
is a gelatinous capsule containing spermatozoa, and it is accepted into the female's reproductive organ, the
cloaca A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilagin ...
, where it is stored until fertilization. The male typically leads the female to the spermatophore for her to pick it up.


Number of mates

Ocoee salamanders do internal fertilization and thus postcopulatory sexual selection plays an important role in their reproduction. In adult ''Desmognathus ocoee'', the mating period lasts from early fall to late spring. Females tend to engage in multiple matings throughout these 9 months, and store sperm in their bodies for extensive periods. This means that a clutch of female eggs can be fertilized by stored sperm from multiple competing males. Usually it is around two to three males. Sperm competition within males is thus an important aspect of sexual selection. Sperm from the males are stored in spermatheca, an organ in the female's reproductive tract, until June and July, during which ovulation, fertilization, and oviposition all occur rapidly. Until the fertilization event, sperm require hospitable conditions to survive in, and are stored in the spermatheca, where they remain viable. Females that experience courtship that ends with successful
insemination Insemination is the introduction of sperm (in semen) into a female or hermaphrodite's reproductive system in order to fertilize the ovum through sexual reproduction. The sperm enters into the uterus of a mammal or the oviduct of an oviparous (eg ...
do not become inseminated when they encounter sexually active males for about four nights after the first insemination. This is caused by a temporary inhibition of female sexual responsiveness, which happens during the initial insemination. Upon the female taking in the spermatophore into her reproductive tract, the sperm mass remains externally visible in the female's cloaca for around 38 hours. This extended stay of the sperm mass likely results in tactical and chemical stimulation, which inhibits the female's sexual responsiveness and her willingness to perform behavioral patterns necessary for successful courtship and sperm transfer. Ultimately, this seems to be a mechanism developed in males to compete with other males for egg fertilization.


Parental care


Oviposition

Oviposition The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typica ...
occurs from June to September on land, after which the female tends her clutch of 9–32 eggs for 6–8 weeks. Clutch sizes can vary from female to female, and is closely related to the body size of the female. During oviposition, females tend to deposit their eggs in cavities under rocks, moss, decaying logs, leaf litter, springs, and behind vegetation or in other crevices. It is important to pick a spot with just enough moisture to avoid the desiccation and loss of eggs.


Egg guarding

After oviposition, maternal care for the clutch lasts for about 3 months, and ends after the eggs hatch into larvae. Maternal care during brooding includes defense against predators, removal of dead eggs, reduction of egg desiccation and fungal infections, and helping the hatchlings with cracking open their shells. If left unguarded, the eggs are in danger of being eaten by surrounding salamanders. Males do not provide resources to either the female or the offspring.
Oophagy Oophagy ( ) or ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek (, "to ...
seems to be a normal behavior in brooding females, but is usually suppressed. In the case of limited foraging availability, disturbed or starved females may choose to eat their own eggs. This may also be done if the egg is dead—the female will eat the dead egg in order to remove it from the clutch before it infects other eggs around it. Fungal infections from dead eggs (if not removed in time) will usually lead to the embryos in viable eggs being smothered and killed.
Larvae A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect developmental biology, development such as insects, some arachnids, amphibians, or cnidarians typical ...
are smaller than in other subspecies, reaching around 8–10 mm at hatching. Upon hatching, ''D. ocoee'' larvae have short and silvery external gills, and they often have distinctive larval spots that other species do not have. The tails of the larvae are keeled and they narrow to a knife edge along the dorsal surface. Once out of the egg, the larvae quickly disperse to a nearby water source. During their development, they are found in shallow waters or in thin films of water, they feed on small aquatic invertebrates. In captivity, they can also eat worms. Usually, the larvae
metamorphose Metamorphosis is a biological process by which an animal physically developmental biology, develops including birth, birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through ...
into their adult form in the following few weeks, the time depending on the availability of food, other resources in the environment, and the temperature.


Conservation status

The ocoee salamander is one of the most common salamanders in the southern Appalachian Mountains. It is believed to have a large and stable population and much of its range lies in state parks or other protected areas. It faces few threats and is listed as being of "
Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
" in the
IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological spe ...
.


References


External links

* {{Taxonbar, from=Q1594834 Desmognathus Endemic amphibians of the United States Amphibians described in 1949 Taxonomy articles created by Polbot