The southern red-backed salamander is a small, dark, slender salamander with a long, rounded tail. A distinct, narrow, red or orange mid-dorsal stripe with saw-toothed edges that correspond with the riblike costal grooves is usually present, though some specimens lack the red dorsal stripe altogether. Also, very unusual individuals with either a gray or white stripe have been reported. The sides are brownish gray with some red pigment. The belly is covered with gray mottling. There are 18 or 19 costal grooves (vertical grooves on the sides of the body).
Similar species: The two species of red-backed salamanders (southern red-backed salamander and Ozark zigzag salamander, P. angusticlavius) that occur in Missouri may be easily confused. The dorsal stripe of the Ozark zigzag salamander is usually very thin (less than one-third of the width of the body), may be broken up into lobes, and is always widest near the hind limbs. Its range overlaps but is generally southwest of the range of the southern red-backed salamander. Despite the overlap in range, the possibility of them hybridizing is remote.
Recent genetic studies of the southern red-backed salamander across its overall US range have revealed five divergent lineages, and it is likely that these will be elevated to full species or subspecies status. Thus, Missouri's populations of southern red-backed salamander may receive a new name in the coming years.
Adult length: 3–4 inches; occasionally to 4¼ inches.
Throughout the northern and southeastern Ozarks.
Habitat and Conservation
The southern red-backed salamander is a terrestrial salamander that commonly lives in upland forests, where it hides under rocks, damp leaves, clumps of mosses, and rotten logs.
This species is most active on the surface during cooler, wet conditions between September and May, but it is difficult to find in the summer. During dry parts of summer, this species may be found near seepages and springs or in thick leaf litter in ravines. If moisture is not present on the ground surface, many salamanders retreat underground via bedrock crevices, or they may utilize burrows created by other animals such as beetles or worms. Southern red-backed salamanders have been documented using the abandoned burrows created by the emergence of periodical cicadas. This species has also been found in the dimly lit area beyond cave entrances.
Southern red-backed salamanders eat ants, beetles, spiders, termites, earthworms, and small snails.
One of the most abundant and dominant species within the forested landscape of south-central Missouri, with density estimates of some 3,000 to 5,000 per acre in appropriate habitats: undisturbed, mature forest as opposed to newly regenerated woodlands.
Taxonomically: Before the mid-1970s, the red-backed salamander of the eastern Missouri Ozarks was considered the eastern red-backed salamander (Plethodon cinereus). Then, researchers showed that the Missouri population is related to the Arkansas population (P. serratus) as well as to populations of red-backed salamanders in several southeastern and southern states. Thus Missouri’s population was reclassified as the southern red-backed salamander (P. serratus).
More recently, genetic studies have discovered that the several disjunct populations of P. serratus constitute five divergent groups that likely warrant full species status, which includes the population in south-central Missouri.
Courtship and mating likely take place between December and March in Missouri. Females lay eggs during late May or June. Presumably the eggs are attached to a thin stalk suspended from the top of a cavity in underground burrows, under rocks, clumps of moss, or rotten logs, as they are in many other Plethodon species. Usually 6 or 7 eggs are produced; they are fertilized as they exit the female’s body, using sperm stored since late winter or early spring. Females remain with the eggs until they hatch, which is sometime between late July and August. The hatchlings begin to emerge on the surface in September and October and are small replicas of the adults, about an inch long. They become sexually mature after about 2 years of age.
This species is most abundant in undisturbed, mature forest and is rarely seen in newly regenerated, second-growth forests. Protection and management of hardwood forests will help keep this salamander common in Missouri.
Protecting habitat for this species simultaneously helps many other species to survive. These salamanders and all the other members of their natural community depend on humans to refrain from destroying, degrading, and fragmenting their native habitat.
These and other lungless salamanders are integral parts of the forested areas they occupy. As predators, they help control the numbers of the insects and other creatures they eat. As prey, the adults, eggs, and young help feed larger predators.
This is a member of the lungless salamander family (Plethodontidae). It’s a large family with 27 genera and about 443 species. The family probably originated in the southern Appalachian Mountains; its members now occur over the eastern half of North America, the West Coast, and into Mexico, Central America, and northern South America. A few species also occur in southern Europe and South Korea.
The lungless salamander family is named because the adults lack lungs and most lack gills; the oxygen they require is taken from their environment through the skin and mucous membrane of the mouth.