First fossil record of Pelekium (Thuidiaceae) from the middle Miocene Zhangpu amber in Asia

Abstract

ABSTRACT Zhangpu amber is an important source of Miocene bryophytes in China. Zhangpu amber originates from the Middle Miocene Climatic Optimum (MMCO), which is well known for the appearance of Dipterocarpaceae-dominated megathermal forests in East Asia. The humid and warm climate of these forests might have triggered the development of diverse epiphytic bryophytes; however, the Middle Miocene fossils of bryophytes are rare in Asia. Here, we present evidence for Pelekium (Thuidiaceae) in Zhangpu amber. The fossil is characterised by: (i) regularly pinnate ramifications; (ii) deltoid leaves with a single and percurrent Costa; (ⅲ) abundant unbranched and uniseriate paraphyllia covering the stems and branches; (ⅳ) differentiated stem and branch leaves. It represents the first fossil record of Pelekium, showing that the genus already existed in Fujian, South China during the Middle Miocene. Our fossil enriches the Neogene fossil record of bryophytes in East Asia. Extant Pelekium species comprises stenoecious plants that are mainly distributed in tropical areas, often grow on bark in humid forests. The occurrence of fossil Pelekium from Zhangpu amber is in good accordance with the palaeoclimatic reconstruction based on the Climate Leaf Analysis Multivariate Program.