What is "gluteus minimus"

n. the innermost of the three gluteal muscles

Gluteus minimus is a fossil from the Upper Devonian of Iowa. It was first collected in 1902, but only described in 1975. Each animal appears as a bi-lobed lens up to , and almost all specimens share the same slight asymmetry. The species is of uncertain affinities, having been thought of as either a fish tooth or a brachiopod.