Notes on the Fauna of the Chipola Formation- XXVIII: On the Occurrence of the Non-marine Genus Mytilopsis (Mollusca: Bivalvia)

Abstract

Material collected from the Chipola Formation , Early Miocene, at Tulane locality 459 on the east bank of the Chipola River, Calhoun County, Florida, has yielded seven valves of Mytilopsis, a genus primarily known from the lower reaches and mouths of rivers within the tropical zone of the Western Hemisphere. Associated with these valves in the collection are more than 100 specimens of a small species of the fresh-water gastropod Planorbis, plus many valves of what appears to be a new species of the estuarine genus Mulinia, abundant donacids, and other forms indicative of a shallow-water environment adjacent to the mouth of a small fresh-water stream. This is the only locality in our Chipola collections with a fauna suggesting such a depositional environment.