The mud salamander (Pseudotriton montanus), is a bright red salamander of the family Plethodontidae. It is found in streams, seeps and swamps and underneath logs, rocks and leaves. It is endemic to the eastern half of the United States with one isolated population in central Mississippi. Mud salamanders have short stocky bodies ranging from 7.5 to 16 cm long. Body color ranges with age and locality with coastal mud salamanders being more dark and drab whilst inland mud salamanders are brighter and have more contrast against the black polka dots that sporadically pattern their bodies. In the earlier years of a mud salamanders life, they tend to have crimson colored body and unspotted stomachs, as they age the salamander becomes a dark red almost purple color and acquires a spotted stomach. mud salamanders have 16 to 17 costal grooves found along the sides of the salamanders body. These salamanders are ectothermic meaning that they cannot control their body temperature and it fluctuates with the temperature. The mud salamander is readily confused with two other species, the red salamander (Pseudotriton ruber) and the spring salamander (Gyrinophilus porphyriticus). It can be distinguished from the Red salamander by having golden pupils and a shorter snout, and can be distinguished from the spring salamander by having a shorter body length and missing the nasal ridge associated with this species. There are four subspecies in the mud salamander complex, these are the Gulf Coast mud salamander, rusty mud salamander, Midland mud salamander and the eastern mud salamander. Taxonomy The taxonomy of Pseudotriton montanus and its closest relatives is unsettled. Several subspecies have been described, and some of these might warrant full species rank. In particular, Pseudotriton diastictus maybe treated as a species or a subspecies (Pseudotriton montanus diastictus). The rest of this article is following the latter position. Description The mud salamander is known for its reddish-brown color, brown eyes, stocky girth, and short tail. It also has between 30 and 40 distinct round black spots on its back by the time it reaches adulthood. The larvae of Pseudotriton montanus are slender and uniformly light in color with brown pigmentation in small irregular blotches and flecks. Younger mud salamanders are typically colored bright red, orangish-brown, or crimson, with unmarked stomachs and separated spots, while older mud salamanders' colors darken with age and take on more of a brown coloring. They also acquire more spots, larger