Eastern Mud Salamander

Pseudotriton montanus is a stout bodied, reddish-brown salamander with black spots and short limbs found in the eastern United States. Total length ranges from 75 - 195 mm in adults, and females tend to be about 20% larger than males (Bruce 1975). Eyes are brown. The body is stout, with 16 or 17 costal grooves. Limbs are short relative to body size. Tail is also short, averaging about 40% of total length. Hatchlings have a snout-vent length of 7.5 - 13 mm. Larvae are stream type. Metamorphs typically measure 35 - 44 mm snout-vent length (Petranka 1998). The color of the dorsum in P. montanus ranges from orange-brown to crimson. The dorsum is covered with irregular, widely spaced black spots. The venter is light or pinkish orange, and may be spotted depending on subspecies. Individuals tend to darken with age, and the spots become less prominent. Juveniles are typically light brown, and develop spots as they approach metamorphosis. Some larvae in the upper Piedmont of North and South Carolina have a streaked pattern, especially on their sides (Petranka 1998).There are currently four recognized subspecies of P. montanus: the eastern mud salamander, P. m. montanus; the midland mud salamander, P. m. diastictus; the Gulf coast mud salamander, P. m. flavissimus; and the rusty mud salamander, P. m. floridanus. P. m. montanus is large, reaching up to 21 cm total length. The venter is usually spotted. It is found along the east coast from New Jersey down to Georgia. P. m. diastictus is the most brightly colored subspecies. Adults are crimson with more sparse spotting than P. m. montanus, and no spotting on the venter. It is found west of the Appalachians, in Ohio, West Virginia, Virginia, Kentucky, and Tennessee. P. m. flavissimus is smaller and more slender than the more northern subspecies (P. m. diastictus and P. m. montanus), reaching a maximum total length of 12 cm. The venter is not spotted. This subspecies is found in easternmost Louisiana, Mississippi, Alabama, Georgia, and western Florida. P. m. floridanus is also small, reaching only 12 cm total length, and is more darkly colored than the other subspecies. The dorsum generally lacks spots, though they may be seen on the tail. The venter is spotted. This subspecies is found in southern Georgia and northern Florida (Petranka 1998).Pseudotriton montanus is similar in appearance to and overlaps in range with P. ruber, the red salamander. The species can be distinguished mainly by eye color and spot patterns. Pseudotriton ruber has yellow eyes, while P. montanus has brown eyes. P. montanus has fewer dorsal spots which are widely spaced and rarely overlap, in contrast to the heavy, often overlapping spotting on individuals of P. ruber. Pseudotriton montanus also tends to have a shorter, more blunt snout than P. ruber (Petranka 1998).The species authority for P. montanus is Baird, 1849 (Hammerson 2004). The species epithet “montanus” means “of or pertaining to mountains” in Latin. Pseudotriton montanus was one of the first Plethodontid salamanders found to be toxic (along with its sister species, P. ruber). Glands in the skin produce the large toxic protein pseudotritontoxin (PTTX). Toxicity appears to vary between subspecies (Brandon and Huheey 1981).

Pseudotriton montanus ranges from New Jersey in the north to the gulf coast, and reaches as far west as Louisiana. The species is most common at elevations below 700 meters and is not found at higher elevations in the Appalachians, resulting in two geographically isolated populations (Petranka 1998). Adults are found in mud or muck in and around swamps, bogs, springs, and streams. They tend to disperse less from their breeding and overwinter sites than the closely related P. ruber, but can occasionally be found under surface cover in wooded floodplains (Petranka 1998).

Adult P. montanus construct and inhabit burrows in muddy sediment near water. Many burrows are located within one meter of the waters edge, but burrows may be found as far as 20 meters from surface water. The burrow entrances lead into water filled channels, which typically open into the nearby waterbody. Younger, smaller individuals are less likely to construct burrows, and are often found under cover in and around the water. The entrance to the burrow is vertical and often covered by leaf litter. The salamanders position themselves with their head near the opening, quickly withdrawing if exposed (Bruce 1975, Petranka 1998). Pseudotriton ruber males become sexually mature about one year after metamorphosis, and begin breeding annually starting the following year. Females take four years to reach sexual maturity, and then reproduce irregularly in subsequent years, often skipping years. Mating occurs in late summer or fall. Eggs are laid during fall or early winter, and they hatch during the winter. The eggs, about 3.5 mm in diameter, are attached to substrates in or near water by a gelatinous stalk. Clutch sizes range from 77 - 192 (126 average), among the highest of any Plethodontid salamander (Bruce 1975, Petranka 1998). Larvae are found under cover in ponds, ditches, seepages, and muddy streams, preferring slow moving regions. The larval stage may last one to two years, with longer larval periods corresponding to colder areas. Larvae rely on a yolk sac for around a month after hatching, then feed primarily on aquatic invertebrates. Metamorphosis occurs between mid-May and early September (Petranka 1998). Pseudotriton montanus grows faster, matures earlier, and produces more offspring than its close relative P. ruber. Richard Bruce (1975) proposes that this r-selection biased life history may be a result of the less stable, more hazardous habitat of P. montanus (Bruce 1975).The diet of P. montanus is not well known. They likely feed on invertebrates and smaller salamanders (Petranka 1998).Several salamander genera within the range of P. montanus have red coloration, including the highly toxic red eft stage of Notophthalmus viridescens. Pseudotriton, Notophthalmus, and Gyrinophilus are believed to be part of a mimicry complex, either Müllerian (in which all species are unpalatable to some degree and all benefit from reduced predation by having similar appearance) or Batesian (where Pseudotriton and Gyrinophilus both mimic the toxic Notophthalmus to reduce predation). The main predators of P. montanus are garter snakes (genus Thamnophis) and water snakes (genus Nerodia). When threatened, P. montanus assumes a defensive posture where the body and tail are coiled over the head (Petranka 1998).

Pseudotriton montanus can most likely tolerate habitat disturbance better than many other eastern salamanders, due to its fossorial, or burrowing, lifestyle and utilization of silted and muddy habitats. Population trends are generally unknown, but it has a wide distribution and many occurrences, so the species is assumed to be healthy and stable. Additionally, because of its wide distribution, P. montanus occurs in many protected areas (Hammerson 2004, Petranka 1998).