Guide to Peronia

Peronia is both heteropolar and heterovalvar. Valves have a narrow, rounded footpole and a wider headpole. The headpole is rounded to subcapitate, while the footpole is narrow and rounded. Valves are heterovalvar in that one valve has a raphe that extends from each pole to approximately one quarter of the valve length. The other valve has a rudimentary raphe that may be evident at the poles, or may be completely absent. Both valves possess a very narrow central sternum. Short marginal spines may be present.

Patrick and Reimer (1966) recorded P. fibula from North America.