|Wrinkled bark beetles|
These beetles are elongate, in size ranging from 5-8 mm, and color ranging from a reddish brown to black. Both the thorax and the elytra are deeply grooved lengthwise, thus giving these beetles their common name. The head is also grooved, and posteriorly constricted into a short but visible "neck". The 11-segment antennae are short, resembling a string of beads, while the mandibles lack cutting edges and are thus nonfunctional. The front legs are short and strongly built,
Adults and larvae live in moist rotten wood that is infested with slime molds, which are believed to be their diet. Instead of using their mandibles to bite, they use the anterior edge of the mentum and swivel their heads to cut off pieces of food. Adults do not make burrows, instead just squeezing between the cell layers of the decomposed wood, generally leaving no visible trace of their passage, while larvae live in short tunnels.
Classification remains controversial, with specialist Ross T. Bell arguing for placement as a tribe Rhysodini of Carabidae, while R. G. Beutel and others argue that larval characteristics indicate that rhysodids are their own family.