Gemellitheca gen. nov., a fertile pecopterid fern from the Upper Permian of the Middle East

Pecopterid fronds bearing typically bilocular synangia, Gemellitheca saudica gen. et sp. nov., are described from the Unayzah plant bed in Saudi Arabia and the Gomaniimbrik Formation of the Hazro inlier in southeastern Turkey. The synangia are attached near the sharply incurved pinnule margin and extend across the whole or almost the whole half-width of the pinnules. Their apices lie near and in some cases over the midrib, and are curved abaxially away from it. The closest comparison is with Dizeugotheca Archangelsky & de la Sota, a Permian pecopterid with transversely placed fructifications which look very similar, but Dizeugotheca is described as having sori with sporangia consistently in groups of four, two of each group being largely overlapped by the other two. Synangia with three or four locules occur in Gemellitheca saudica but are rare. The affinities of Gemellitheca are considered to lie with the marattialean ferns. A number of its characters are shared with species of Scolecopteris Zenker.