Bryozoans from the lower Miocene Chipola Formation, Calhoun County, Florida, USA

Abstract

The first comprehensive study of the bryozoan fauna from the upper lower Miocene (Burdigalian) Chipola Formation was produced in 1968 by Reginald J. Scolaro in his Ph.D. dissertation but, unfortunately, has never been published. In the present work, based on museum as well as newly collected material, we review and revise the taxonomy of the Chipola Formation bryozoans. Sixty species, comprising five cyclostomes and 55 cheilostomes, are described. Twenty-five of the cheilostome species are new: Nellia winstonae n. sp., Paralicornia interdigitata n. sp., Floridina subantiqua n. sp., Thalamoporella papalis n. sp., Thalamoporella hastigera n. sp., Thalamoporella polygonalis n. sp., Thalamoporella bitorquata n. sp., Thalamoporella ogivalis n. sp., Puellina quadrispinosa n. sp., Spiniflabellum jacksoni n. sp., Trypostega vokesi n. sp., Exechonella minutiperforata n. sp., Adeonellopsis sandbergi n. sp., Escharoides joannae n. sp., Stylopoma leverhulme n. sp., Stylopoma farleyensis n. sp., Margaretta pentaceratops n. sp., Cheiloporina clarksvillensis n. sp., Hagiosynodos simplex n. sp., Vix scolaroi n. sp., Cigclisula solenoides n. sp., Turbicellepora giardinai n. sp., Pleuromucrum liowae n. sp., Pleuromucrum epifanioi n. sp., and Schizolepraliella nancyae n. gen. et n. sp. Of the previously described species, 13 are extant and characterized by a Western Atlantic or pantropical distribution, while 7 species are known only as fossils. In Florida, the Chipola Formation reflects the last truly tropical climatic conditions during the Miocene and also represents the last major transgression in the Western Atlantic before sea-level fell due to the onset of late Miocene glaciation.