Plethodon serratus was formerly considered a subspecies of the widespread species Plethodon cinereus until studies suggested that the southern forms were genetically distinct enough to warrant being considered a separate species.
Laboratory tests with southern red-backed salamanders indicate that chemoreception is important in communication between individuals. Animals are able to distinguish between their own scent marks and those of other salamanders. The ability of these salamanders to distinguish the presence of others helps them maintain territories. Intruders avoid confrontations with resident salamanders based on this scent recognition.
Southern red-backed salamanders communicate with each other during territorial disputes using visual, tactile, and chemical clues. In addition to the aggressive and submissive behaviors listed in the "Behavior" section, these salamanders also communicate using some non-aggressive and passive-aggressive behaviors. They may contact other individuals with their nasal cirri or rub their chin against the other individual. Southern red-backed salamanders use tail wagging, mouth snapping, and looking at/away from another individual to communicate passive-aggressive behaviors.
Communication Channels: visual ; tactile ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; chemical
Plethodon serratus is currently not listed in any federal or state endangered species program. The species is generally common over much of its range, where suitable habitat remains. However, Plethodon serratus occurs mostly in isolated pockets in central Louisiana. Strip mining operations have resulted in further fragmentation of populations. At least one small population has been extirpated in west-central Louisiana due to strip mining. Others have likely shared a similar fate. The population of P. serratus in this state should be monitored closely since it is isolated from other populations.
The habitat of Plethodon serratus is being degraded in areas of the southern U.S. where intensive plantation forestry for pine trees is conducted. Populations of the species in Georgia are declining as a result of these forestry practices.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
There is no free larval stage in this species.
Development - Life Cycle: metamorphosis
These salamanders are totally harmless to human interests.
Small woodland salamanders help to cycle nutrients in woodland habitats and thus help maintain a healthy forest, certainly a benefit to humans. Their populations are indicators of the health of woodland ecosystems. Woodland salamanders are sometimes collected as fish bait.
Positive Impacts: research and education
Plethodontid salamanders have been shown to be ecologically important in temperate forest ecosystems. The total biomass of plethodontid salamanders in a New Hampshire forest was shown to be equal to that of small mammals and greater than the biomass of birds. Plethodon cinereus, a close relative of P. serratus, made up 93.5% of the total salamander biomass. It is certain that woodland salamanders in the genus Plethodon play a significant role in the nutrient flow and food webs of their ecosystems. In addition, studies of species such as P. serratus can indicate environmental problems in their woodland habitats.
Results from an experiment that altered the densities of other Plethodon salamanders, including Plethodon jordani, showed that when densities of the other species were reduced, there were no detectable effects on the density of southern red-backed salamanders. This finding suggests that P. serratus is not in direct competition with other, larger plethodontid salamanders.
Southern red-backed salamanders eat small invertebrates. The highest percentage of their food by volume comes from ants and beetles. They also eat snails, annelids, mites, spiders, pseudoscorpions, millipedes, centipedes, isopods, and several other types of insects.
Animal Foods: insects; terrestrial non-insect arthropods; mollusks; terrestrial worms
Primary Diet: carnivore (Insectivore , Molluscivore , Vermivore)
Southern red-backed salamanders occur in four disjunct populations in the southern United States. These ranges are: the Salem Plateau of southeast Missouri, the Ouachita Mountains of extreme southeast Oklahoma and west-central Arkansas, the Piedmont Plateau and Blue Ridge Mountains of northwest Georgia and nearby portions of extreme eastern Alabama, eastern Tennessee, and western North Carolina, and, finally, in isolated locations in central Louisiana.
Biogeographic Regions: nearctic (Native )
Over most of its range, Plethodon serratus occurs in upland deciduous forests that contain abundant rocks or logs. In central Louisiana, this species lives among rocky hillsides in forests of longleaf pine. Plethodon serratus occurs in a range of moisture conditions, from moist mesic to drier, better-drained habitats. During the spring months from April to early June, P. serratus is associated with thick leaf litter and dead, downed wood. From September to March, these salamanders often take refuge under rocks and logs. During the warm summer months (June, July, and August) P. serratus tends to stay underground. During this time, these salamanders may burrow up to one meter into the soil.
Range elevation: 1690 (high) m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
There have not been any published studies on the average or maximum lifespan of southern red-backed salamanders. Other salamanders in this genus have been known to live up to 25 years in the wild in rare cases. Since southern red-backed salamanders do not reproduce until they are 2 or 3 years old and some populations reproduce biennially, it is reasonable to assume a lifespan of several years to be normal in this species.
Southern red-backed salamanders are small, narrow-bodied salamanders with short legs; they are best identified by their mid-dorsal stripe extending from the neck area to the tail. The stripe is orange or reddish, often with a serrated edge, especially in the Ouachita Mountain and Louisiana populations. Other populations may have less pronounced serration in the stripe. The serrated nature of the stripe led to the naming of this species P. serratus. Red coloring from the back may blend into the sides, but not on the belly. "Lead back" coloration, in which the dorsal coloration is dark, is also found in this species, similar to the lead-back morph found in their close relative, Plethodon cinereus. Southern red-backed salamanders may have from 18 to 21 costal grooves, varying geographically. The most common number of costal grooves for the species in Missouri is 18; Louisiana, Ouachita, and Blue Ridge individuals most commonly have 19; individuals in Georgia and Alabama have 20 or 21 grooves. Studies from three different geographic populations of these salamanders produced similar body size results. Adults range in size from 31 to 47 mm measured from snout to vent. Total length of adult salamanders is between 81 and 105 mm. Juveniles similar in color to adults.
Range length: 8.1 to 10.5 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
No specific studies have been published on predation on southern red-backed salamanders. The most likely predators include small woodland snakes, shrews, birds, small mammals like skunks, and perhaps larger salamander species.
Anti-predator Adaptations: cryptic
Competition occurs among males for female mates. Males defend their territories more aggressively against other males compared to females, especially during the breeding season. There have not been any studies conducted specifically on the courtship behavior of Plethodon serratus. However, it can be assumed that their mating systems would be similar to their better-studied close relative, Plethodon cinereus.
The breeding season for Plethodon serratus is during the cool, moist winter months. Mating occurs between December and March. Females lay between 4 and 10 eggs in an underground cavity between May and July. They presumably attend their eggs during incubation, as do related species. Egg capsules average 4.5 mm in diameter. Juveniles complete the larval stage within the egg and hatch and emerge as independent, terrestrial salamanders by September or October.
Plethodon serratus is first ready to reproduce between 24 and 36 months after hatching. Female salamanders were shown to breed annually in northern Georgia and Arkansas, and biennially in southeast Missouri. Regional differences in breeding interval has been observed in populations of other Plethodon salamanders as well, including the red-backed salamanders (Plethodon cinereus) and slimy salamanders (Plethodon glutinosus). It is likely that the Missouri population is exposed to climatic factors, such as temperature and rainfall, that cause it to have a different reproductive cycle than more southern populations. Other factors may include a more discontinuous activity period during winter when females must accumulate energy reserves in order to breed successfully.
Breeding interval: Females breed biennially or annually. Males breed annually.
Breeding season: Breeding occurs from December to March. Oviposition occurs from May to July.
Range number of offspring: 4 to 10.
Average time to hatching: 2 months.
Range age at sexual or reproductive maturity (female): 24 to 36 months.
Range age at sexual or reproductive maturity (male): 24 to 36 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
Assuming that their habits are similar to their close relative, Plethodon cinereus, with which they were once considered conspecific, female Plethodon serratus must accumulate sufficient energy to develop and yolk eggs, defend a nesting territory, and then to remain with their eggs for the approximate two-month incubation period. Males must expend energy in defending territories, producing sperm and spermatophores, and in courtship.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
The southern red-backed salamander (Plethodon serratus) is a species of salamander endemic to the United States.[2] It is found in four widely disjunct populations: one in central Louisiana; one in the Ouachita Mountains of Arkansas and Oklahoma; one in central Missouri; and one from southeastern Tennessee, to southwestern North Carolina, western Georgia, and eastern Alabama. It is sometimes referred to as the Georgia red-backed salamander or the Ouachita red-backed salamander. It was once considered a subspecies of the red-backed salamander, Plethodon cinereus.
The southern red-backed salamander is typically gray or black in color, with a red-brown, fading stripe across the width of its back. It grows from 8 to 11 cm (3 to 4 in) in length. Similar to Plethodon cinereus, Plethodon serratus comes in several atypical color variations. The typical red backed phase with a red dorsal stripe consists of most individuals. The atypical variations include a lead backed phase with a dark grey stripe, a silver back phase with a light grey dorsal stripe, hypomelanistic (leucistic) variations of the red backed form, and the rare white backed, or ghost phase. Unlike P. cinereus, P. serratus has not yet been found to have an erythristic variation.[3]
Mostly nocturnal, it is often found under ground debris in moist, forested areas. In dry seasons, it moves closer to permanent water sources. Its primary diet is small arthropods and mollusks.
The southern red-backed salamander (Plethodon serratus) is a species of salamander endemic to the United States. It is found in four widely disjunct populations: one in central Louisiana; one in the Ouachita Mountains of Arkansas and Oklahoma; one in central Missouri; and one from southeastern Tennessee, to southwestern North Carolina, western Georgia, and eastern Alabama. It is sometimes referred to as the Georgia red-backed salamander or the Ouachita red-backed salamander. It was once considered a subspecies of the red-backed salamander, Plethodon cinereus.
