New material of Macralethopteris from the Early Permian Jambi flora (Middle Sumatra, Indonesia) and its palaeoecological implications

New material of the Early Permian alethopterid genus Macralethopteris is examined in detail. The material stems from different locations and statistical comparison of the morphological differences between collections suggests that the material is derived from several populations of a single species. Comparison is made with related Cathaysian and Euramerican species, showing the isolated occurrence of Macralethopteris in the Cathaysian region. Characteristics of the species and possible ecological implications suggest that Macralethopteris hallei grew in more mesic circumstances than usually associated with alethopterids. It is argued that M. hallei might have been a relatively small alethopterid with possible cormous growth.