Crossotheca urbani sp. nov., a male fructification from the Pennsylvanian (Desmoinesian series, Verdigris formation) of Missouri, U.S.A.

Abstract

Crossotheca urbani Cridland & E. L. Darrah is described from the Verdigris Formation, Desmoinesian Series, Pennsylvanian of Missouri, U.S.A. In general aspects, this species resembles C. sagittata and C. boulayi but the laminate fertile regions of the pinnules are ovoid to oblong. Two rows of corrugated impressions on the pinnules are taken to represent sporangia. Sterile foliage is unknown. The species is known only from the holotype, a specimen preserved in an ironstone nodule, which was studied by a plastic transfer technique.