Gleichenipteris antarcticus gen. et sp nov from the Triassic of Antarctica

A new fern, Gleichenipteris antarcticus, is described from permineralized sporangia found in the Triassic of Antarctica. Sporangia are attached to a foliar unit via a vascularized receptacle although the lamina is poorly preserved. Sori are composed of three to five sporangia per sorus, each with simple maturation. Each leptosporangium has a vertical to oblique annulus and a short stalk. Spores are trilete, triangular to subtetrahedral and up to 40 mu m in diameter; surface ornamentation is reticulate. Sporangia share the most similarities with the extant family Gleicheniaceae and the contemporaneous genera Wingatea and Gleichenites. The sporangia are found closely associated with the putatively gleicheniaceous stem genus Antarctipteris. Gleichenipteris has oblique to vertical annuli, no stomia, few sporangia per sorus,several sori per pinnule, and triangular spores, which is a combination of soral and annular characteristics that differentiates them from currently known species and which contributes to the known variability of characteristics in the history of the family. (C) 2000 Elsevier Science B.V. All rights reserved.