First Fossil Fokienia (Cupressaceae) in South China and Its Palaeogeographic and Palaeoecological Implications

Xinkai Wu,Songyao Jiang,Tatiana M Kodrul,Qianyi Yin,Hao Zhang,Natalia P Maslova,Jianhua Jin,Cheng Quan

doi:10.3389/feart.2021.709663

Xinkai Wu, Songyao Jiang + Show 6 more

Open Access

https://doi.org/10.3389/feart.2021.709663

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Abstract

Fokienia A. Henry &amp; H. H. Thomas is a monotypic genus of the Cupressoideae Rich. ex Sweet (Cupressaceae), native to subtropical evergreen mesophytic forests in South China, northern Laos and Vietnam. The fossil record of Fokienia is very scanty, with only one known occurrence of foliage in the Oligocene of Longjing, Jilin, China. Here we report the fossil foliage of Fokienia discovered in the Miocene Erzitang Formation of the Guiping Basin, South China, which is similar to that of the only extant species Fokienia hodginsii in both macromorphological and epidermal features. This species is the earliest fossil record within the modern distribution area of Fokienia and the only fossil species for which morphology and anatomy have been studied in detail. Fossil evidence suggests that the genus Fokienia was present at middle latitudes of the Northern Hemisphere in the Oligocene and spread to South China during the Miocene. Due to physiological adaptations to warm-wet environments and weak cold tolerance, Fokienia migrated southward, as global climate cooling gradually drove it to extinction in the mid-latitudes. The ecological niche of the extant species, and co-existing plant fossils, suggest that the fossil assemblage represents the remains of an evergreen broad-leaved and conifer mixed forest growing under humid and warm Miocene climate.

Highlights

We describe a new fossil species of Fokienia on the basis of foliage from the Miocene of South China and discuss the phytogeographical and palaeoecological implications of this genus
The fossils studied here were collected from the Miocene Erzitang Formation in the Guiping Basin located east of Guiping City, Guangxi, South China
The leaves of many genera within this subfamily, such as Fitzroya Hook. f., Actinostrobus Miq. and Callitris Vent., are arranged in alternating whorls of three, which are different from the leaves of our new fossil species from Tengxian in which leaves are arranged in whorls of four

Summary

INTRODUCTION

The only extant species, Fokienia hodginsii (Dunn) Henry & Thomas is an evergreen tree species native to subtropical evergreen mesophytic forests in South China (except Hainan Island), northern Laos and Vietnam (Figure 1; Farjon, 2005). Fokienia has significant economic value, its high-quality timber is extensively used for building materials, furniture construction and fine handicrafts This conifer is used in forest plantations, and its valuable essential oil is used in pharmaceuticals and cosmetics (Fu et al, 1999). Chamaecyparis) hodginsii by Dunn (1908), and Henry and Thomas (Henry, 1911) assigned this species to a new genus Fokienia based on the morphological characteristics of its seed cones, seeds and leaves. We describe a new fossil species of Fokienia on the basis of foliage from the Miocene of South China and discuss the phytogeographical and palaeoecological implications of this genus

MATERIALS AND METHODS

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DATA AVAILABILITY STATEMENT