Trilobite
Order Proetida classification. The Phillipsiidae are the last surviving
family of trilobites, with a geologic time range beginning
in the
Lower
Mississippian (Kinderhookian stage), to the Upper Permian.
The Phillipsiidae are taken as a subfamily within Proetidae
by some trilobite researchers, while others combine families
Phillipsiidae and Proetidae.