Alethopteris sp.

Form belonging to the Alethopteris lonchitifolia-missouriensis-westphalensis complex, perhaps the fragment represents a pinna originating from the basal part (with longer kind of pinnules) of a frond of Alethopteris westphalensis Wagner 1968. 

Diagnostic characters of the specimen: 

Pinnules with broadly confluent basiscopic sides; pinnules inserted slightly obliquely (~70-80°) on pinna; pinnule length ~2 cm; pinnule width ~5 mm; lateral vein density ~32/cm; pinnule sides fairly straight to slightly convex; midvein fairly thick, straight and persisting into pinnule apex; lateral veins generally once forked, approach pinnule border at approximately right angle.