Midwestern USA USA
Geological Time: Devonian Upper Devonian
View of a specimen of Anictosphaera progressa McClellan, 1973
The identification is based upon:
McClellan, P., 1973: Siluro Devonian microfaunal biostratigraphy in Nevada. Bulletins of American Paleontology, 62 (274), 235-375.
Available online at the Biodiversity Heritage Library published by the Paleontological Research Institution, Ithaca, New York.
Plate 34, Fig. 1-2