Cuticular characteristics of Neuralethopteris jongmansii LAVEINE (medullosalean foliage, Westphalian, Intrasudetic Basin, Poland)

Abstract

Foliar cuticles are described for the first time from the medullosalean pteridosperm Neuralethopteris jongmansii LAVEINE. This species is not as common, either in abundance or distribution, as Neuralethopteris schlehanii (STUR) CREMER, the abaxial cuticle of which has paracytic (in morphological sense) and anomocytic stomata. In contrast, the stomata of Neuralethopteris jongmansii occur on both abaxial and adaxial cuticles and are anomocytic, monocyclic with prominent proximal papillae and sometimes paracytic. The epidermal cells of N. jongmansii are papillate and partly differ from N. schlehanii cuticles. However, there is a striking similarity between the foliar cuticles of N. jongmansii and Neurodontopteris auriculata (BRONGNIART) POTONIE. Although N. auriculata is a much younger fossil-species with pinnules that are more robust and of a different shape than N. jongmansii, their epidermal structures are practically the same – polygonal papillate cells, anomocytic, monocyclic stomata with prominent proximal papillae. Even their stomatal densities are equivalent. Despite this, there is a marked difference in the frond architecture of both genera. Neuralethopteris has „alethopterid“ bifurcate-pinnate frond architecture, Neurodontopteris has quite a different bifurcate-semi-pinnate frond architecture. Based on comparison of the cuticles, Neuralethopteris jongmansii and Neurodontopteris auriculata appear very similar and it may reflect common palaeoenvironmental demands.