A new gigantopterid plant with cuticles from the Permian of South China

Abstract

A new species of gigantopterid leaf Gigantopteridium marginervum sp. nov. is described from the uppermost bed of the Kuhfeng Formation (Middle Permian, equivalent to the Wordian of the Guadalupian) of Jiangsu Province, China. The leaf is apparently simple with pinnately organized venation similar to that of Gigantopteridium americanum (White) Koidzumi in which the tertiary venation forms sutural veins between adjacent pairs of secondaries. A distinct intramarginal vein is also present. The cuticle is well preserved with cyclocytic stomata on both surfaces. Subsidiary cell of stomata on the adaxial surface form a ring of thickened cuticle surrounding each stomatal pore, while subsidiary cells of stomata on the abaxial surface are papillate with each stomatal pore surrounded or partially overarched by two to seven papillae. Gigantopteridium marginervum sp. nov. exhibits some superficial similarities both in venation and cuticular structure to the leaves of Aipteris (= Scytophyllum). The thick cuticle of G. marginervum makes it unlikely that these leaves were produced by true ferns and indicates instead that the fossil leaves assigned to G. marginervum sp. nov. were produced by some kind of seed plant. Based on cuticular characters the systematic position and the palaeoecological implications of the new species are discussed.