A new species of permineralised cardiocarpalean ovule from the Early Permian Taiyuan Formation of northern China

Abstract

A new species of cardiocarpalean ovule is described and diagnosed from Early Permian coal balls collected in Shanxi Province of north China and is named Cardiocarpus tuberculatus sp. nov. Ovules are small, have 180° rotational symmetry and show a tuberculate outer margin resulting from variation in integumentary thickness. The integument has a prominent uniseriate epidermis, sarcotesta with two zones, a uniformly thick sclerotesta of elongated fibre cells and a uniseriate endotesta. The integument is free from the nucellus except at the chalaza, and distally the ovule has a small but prominent nucellar beak. A single vascular trace enters the ovule at the chalaza and divides within the sarcotesta to produce two smaller integumentary bundles in the major plane while continuing onwards to the base of the nucellus where it forms a vascularised nucellar sheath. The pattern of vascularisation is consistent with that of the cardiocarpalean ovule Cardiocarpus Brongniart but it has a more extensively vascularised nucellus than the majority of Cardiocarpus species. Its variably thick sarcotesta and tuberculate integument distinguish it from all other species of the genus. Cardiocarpus tuberculatus sp. nov. is compared to other cardiocarpalean ovules and its occurrence in the Early Permian Cathaysian flora of northern China is discussed.