Two new Castanopsis (Fagaceae) species based on cupule and foliage from the upper Miocene of eastern Zhejiang, China

Abstract

Two new species, Castanopsis praefissa R.Y. Li et B.N. Sun sp. nov. and Castanopsis praeouonbiensis R.Y. Li et B.N. Sun sp. nov., are described from fossil specimens collected from the upper Miocene Shengxian Formation, Zhejiang Province, Southeast China. The fossil leaves are obovate to elliptical with serration mostly confined to the upper 1/3 of the lamina, pinnate venation, straight anticlinal walls and cyclocytic stomata. The fossil cupule is globose with fasciculate and branched spines, and a broadly ovate nut scar. The fossil leaves and cupule have been compared with those extant and other fossil species hitherto described in this genus. Castanopsis praefissa shows the closest affinity to C. fissa, and C. praeouonbiensis closely resembles C. ouonbiensis. Castanopsis fissa has toothed leaves and scaly cupules, whereas C. ouonbiensis has untoothed leaves and spiny cupules. Furthermore, they were not collected from the same site. So it is reasonable to assign them to two different species, rather than to one. Castanopsis praeouonbiensis and C. praefissa became extinct in this area because of the cooling climate from the late Miocene to the present day in Zhejiang Province.