Pipiscius

Pipiscius is an extinct genus of lamprey that lived about 300 million years ago, during the Middle Pennsylvanian Epoch of the Carboniferous Period. The genus contains a single species, P. zangerli, known from the Mazon Creek fossil beds located in present-day Illinois.

It has a distinctive crown-like mouth comprising a ring of radially arranged teeth. However, some specimens assigned to the coeval lamprey Mayomyzon, also found in the Mazon Creek beds, also have similar mouthparts. Since Pipiscius does not have many any other defining features, it has been suggested that the two genera are synonymous, with the name Mayomyzon having priority.