Length: 10 - 13 mm
The highland species Platynus tenuicollis is found in rich-soiled ravines, and beside streams. These beetles may be found under rocks as well as walking on the ground. They are most active at night, when they may be found on tree trunks, and they are also attracted to lights.
The species is dark, but has lighter, or reddish-brown, pronotal and elytral margins, and elytral suture. Also lighter, or reddish-brown, are the tarsi, as well as the antennae (except basally).
Photo data: 11 August 2012. Holly River State Park, Webster County, West Virginia. This is a male.