A NEW OLIGOCENE CALOCEDRUS FROM SOUTH CHINA AND ITS IMPLICATIONS FOR TRANSPACIFIC FLORISTIC EXCHANGES
A NEW OLIGOCENE CALOCEDRUS FROM SOUTH CHINA AND ITS IMPLICATIONS FOR TRANSPACIFIC FLORISTIC EXCHANGES
复制标题
华南渐新世新的柏柏属植物及其对跨太平洋植物区系交流的影响
DOI：
10.3732/ajb.1100331
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发表时间：
2012-01-01
影响因子：
3
通讯作者：
Xie, Zhiming
中科院分区：
文献类型：
--
作者：
Shi, Gongle;Zhou, Zhiyan;Xie, Zhiming
研究目的：翠柏属是现今东亚-北美西部间断分布的典型属之一。方法：本文首次报道该属一新种，该种化石来自广西渐新世宁明组，现主要分布于亚洲东部。华山肖楠（Calocedrus huashanensis sp. nov.）macrolepis和C.在叶枝的形态上与台湾产的它显示了一个一般的相似性，该属的北美化石代表在交替分枝的叶枝，但明显不同于欧洲古近纪物种的特点是相反的分支多叶shoots.Conclusions：这一发现提供了新的证据，该属之间的植物区系交流的东亚和北美的渐新世（最有可能在始新世）之前，大概是通过白令陆桥。目前化石的扁平多叶枝和二形叶，角质层较薄，气孔孔开放，保卫细胞浅凹，表明华南宁明地区渐新世气候相当潮湿。
Premise of the Study: Calocedrus is among the genera with a typical eastern Asian-western North American disjunct distribution today. The origin of its modern distribution pattern can be better understood by examining its fossil record.Methods: The present article reports for the first time a new fossil species of this genus based on compressed material from the Oligocene Ningming Formation of Guangxi, South China, in its present major distribution area in eastern Asia.Key Results: Calocedrus huashanensis sp. nov. is most similar to the two extant eastern Asian species, C. macrolepis and C. formosana, in gross morphology of foliage shoots and bears a close resemblance to the latter in cuticle structure. It shows a general similarity to the North American fossil representatives of the genus in alternately branched foliage shoots but is clearly different from the European Paleogene species characterized by oppositely branched leafy shoots.Conclusions: This discovery provides new evidence for the floristic exchange of this genus between eastern Asia and North America before the Oligocene (most likely in the Eocene), presumably via the Bering land bridge. The flattened leafy shoots and dimorphic leaves with thin cuticle, open stomatal pits, and shallowly sunken guard cells of the present fossils suggest a rather humid climate during the Oligocene in the Ningming area, South China.