Permineralized Cardiocarpalean Ovules in Wetland Vegetation from Early Permian Volcaniclastic Sediments of China

Abstract

In this paper we report the first occurrence of permineralized plant fossils in volcaniclastic lithologies from China and in doing so describe a new species of cardiocarpalean ovule permineralized within tuffaceous sediments from a recently discovered locality near Pingquan, Hebei Province, North China. The tuff is part of the Early Permian Taiyuan Formation which contains a diverse fossil plant assemblage that includes cordaitean spermatophytes, lepidodendralean lycophytes, equisetophytes, and filicalean ferns, all of which were typical of Permian floras of northern China at this time. Specimens of Cardiocarpusdabiziae sp. nov. have the characteristic platyspermic shape and vascularization of cardiocarpalean ovules, and display prominent protuberances on the exterior of the integument. The integument of the ovule is composed of three layers; a thick sarcotesta, a thin and comparatively dense sclerotesta, and a single layer of large endotesta cells. The pollen chamber produces a slender nucellar beak. In several specimens the megaspore membrane contains well‐developed tissue of the megagametophyte. The ovules have prominent external integumentary protuberances which suggest that well‐developed systems of plant/animal interactions were operative in Early Permian wetland biotas of the Cathaysian realm.