CHONETOID GENUS PLICOCHONETES (BRACHIOPODA) IN MORROWAN/ATOKAN (PENNSYLVANIAN) OF UNITED STATES

Chonetoid brachiopods are common in Pennsylvanian beds of the United States. During the author's study of Pennsylvanian chonetoid brachiopods from Ohio, the species Plicochonetes dotus Sturgeon and Hoare was found to be particularly interesting. This brachiopod species is finely ribbed (capillate) but the type species of genus Plicochonetes is coarsely ribbed (costate). However, many different species of chonetoid brachiopods in North America and other parts of the world were assigned to the genus Plicochonetes by different authors in the past. The type location of P. dotus (Lower Mercer, Morrowan/Atokan) was revisited in this present study, and a new nearby locality with excellent preserved specimens was found. The ontogenetic series of this species has been determined. Analysis of material confirms author's initial impression that the present understanding of genus Plicochonetes is too wide and further study of this genus is necessary. This present work is part of such effort. Further study of the genetic affinities of P.dotus is in progress. Chonetoid brachiopods closely related to P.dotus from beds of similar age but from other North American localities are studied by the author.