Revision of the Pterophyllum species (Cycadophytina: bennettitales) in the Carnian (Late Triassic) flora from Lunz, Lower Austria

A revision of the genus Pterophyllum in the famous Late Triassic flora of Lunz, Lower Austria, based on macromorphology, biometry, and epidermal anatomy is presented. Two distinct species, Pterophyllum filicoides and Pterophyllum brevipenne, are recognized. Other Pterophyllum species described from Lunz by D. Stur and F. Krasser in the late 19th and early 20th centuries are interpreted as conspecific with either of these two species; others represent cycadalean foliage assignable to the genus Nilssonia. Full-grown P filicoides leaves are more than 45 cm long and oblong to broadly oval in outline; the lamina is subdivided into narrow leaf segments up to I I cm long. Full-grown leaves of P. brevipenne are considerably smaller than those of R filicoides, and lanceolate to spatulate in outline; the lamina is subdivided into leaf segments up to 2.7 cm long. Pterophyllum is by far the most common element in the Lunz flora. Moreover, the species from Lunz range among the earliest representatives of this genus in the fossil record. This suggests that certain Bennettitales locally became significant elements of the vegetation relatively early in their evolutionary history. (C) 2007 Elsevier B.V All rights reserved.