Macroleter had a 8 cm skull, and an overall length of 75 cm. It was generally lizard-like in build with a rather flat and broad skull. The teeth were small and pointy, indication it predominately hunted insects and other small invertebrates.
Seymouria agilis (Olson, 1980) that is known from only one specimen (holotype UCMP 143 277) was originally thought to be a retile-like amphibian and assigned to the genus Seymouria. The find consists of a nearly complete skeleton from the Chickasha Formation of Oklahoma. In 2001, the find was reassigned by Laurin and Reisz to Macroleter. Tokosaurus, another generalized anapsid genus of uncertain phylogeny, has also been reassigned to Macroleter.