Involucre fossils of Carpinus, a northern temperate element, from the Miocene of China and the evolution of its species diversity in East Asia

Abstract

East Asia has long been recognized as a major center for temperate woody plants diversity. Although several theories have been proposed to explain how the diversity of these temperate elements accumulated in the region, the specific process remains unclear. Here we describe six species of Carpinus , a typical northern hemisphere temperate woody plant, from the early Miocene of the Maguan Basin, southwestern China, southern East Asia. This constitutes the southernmost, and the earliest occurrence that shows a high species diversity of the genus. Together with other Carpinus fossil records from East Asia, we show that the genus had achieved a high diversity in East Asia at least by the middle Miocene. Of the six species here described, three have become extinct, indicating that the genus has experienced apparent species loss during its evolutionary history in East Asia. In contrast, the remaining three species closely resemble extant species, raising the possibility that these species may have persisted in East Asia at least since the early Miocene. These findings indicate that the accumulation of species diversity of Carpinus in East Asia is a complex process involving extinction, persistence, and possible subsequent speciation.

Fossil infructescence from southwestern China reveals Paleogene establishment of Cladrastis in Asia

“…A similar phenomenon is also found in other taxa uncovered from the Maguan Basin such as Carpinus L., Pterolobium R. Br. ex Wight et Arn., Sladenia Airy Shaw, and Ulmus L (Jia et al, 2017;Zhang et al, 2018;Xue et al, 2020;Jia et al, 2021). They are all morphologically undistinguished from the extant species which still inhibit in the region close to the fossil sites.…”

“…From a floristic perspective, in-depth studies have been carried out for the geographically close Wenshan and Maguan paleofloras, and both represent subtropical evergreen forests and share similar elements (Huang, 2017;Jia, 2018). The major difference between the two paleofloras is that Maguan paleoflora contains numerous extinct taxa such as extinct lineage of Carpinus L., Cedrelospermum Sapota, and Deviacer Manchester (Jia et al, 2015;Jia, 2018;Xue et al, 2020), but these taxa are not present in the Wenshan paleoflora (Huang, 2017). In particular, the Maguan flora has yielded more than 400 winged fossil fruits of Cedrelospermum, an extinct genus with extensive fossil records in the Cenozoic of Europe and North America (Jia et al, 2018).…”

Megafossils of Betulaceae from the Oligocene of Qaidam Basin and their paleoenvironmental and phytogeographic implications

“…Betulaceae Gray, which consists of six genera ( Carpinus L., Corylus Ascherson, Ostrya Scop., Ostryopsis Decne, Alnus Mill., and Betula L.) and 150–200 species, is an important component of the deciduous broad-leaf forest in the north temperate zone today ( Li and Skvortsov, 1999 ). Betulaceous fossils are common in Cenozoic floras of the Northern Hemisphere ( Crane, 1981 ; Chen, 1994a , 1994b ; Liu, 1996 ; Lin et al., 2010 ; Liu et al., 2014 ; Xue et al., 2020 ). They are often found in different floras such as northern temperate deciduous broad-leaf forest, subtropical deciduous broad-leaf forest, and subtropical evergreen and deciduous broad-leaf mixed forest ( Tao and Du, 1987 ).…”

Plastid phylogenomics and fossil evidence provide new insights into the evolutionary complexity of the ‘woody clade’ in Saxifragales

“…Given that fossils represent the remains of past plants, they have the capacity to unveil intermediate evolutionary connections from the geological past, thereby offering valuable evidence for comprehending the evolution of the tree of life [34][35][36][37]. The combination of molecular and fossil evidence is recommended as an efficient approach for inferring the evolutionarily complex events that might result in phylogenetic recalcitrance in the angiosperm tree of life [16,30,38,39].…”