Fritzolenellus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites, with three known species.

[2] It lived during the early part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago.

Fritzolenellus is the genus closest to the common ancestor of Mummaspis, Laudonia, the Biceratopsinae and the Bristoliinae.

This clade is the sister group Wanneria walcottana and of the Holmiidae.

The generic name is a combination of the genus Olenellus, to which these species were originally assigned,[4][5] and a reference to William Henry Fritz (1928-2009), a paleontologist who worked on olenelloid trilobites.