New Jurassic protocycadalean ovuliphores and the origins of the Cycadales

Abstract

Ovuliferous spikes with two lateral rows of ovules are described from the Callovian of Georgia. The ovules are large, orthotropous, oblique to the stout rachis, with a scar of subtending bract at the base. They show a relatively thin integument and a bulky nucellus topped by a broad nucellar beak. This find constitutes a new genus Baruligyna gen. nov. closely related to the previously described Semionogyna Krassilov et Bugdaeva from the Lower Cretaceous of Transbaikalia. Both are associated with pteridosperm-like foliage. In the case of Baruligyna, the associated leaves are of a Pachypteris morphotype, bipinnate with thick leathery pinnules similar to the ovules in shape and dimensions. This group of Mesozoic plants is considered as transitional between the Permian callipterids and the Mesozoic cycads indicating the origin of Cycas-type ovuliphores ("macrosporophylls") form planated bracteate strobili.