中国首次发现白垩纪桫椤科茎干化石 |
|
关键词:Cyatheaceae tree fern trunk anatomy Cyathidites spore Cretaceous Heilongjiang |
基金项目:国土资源部部门预算项目“地质遗迹标本采集、购置与综合研究”(编号: 121113000000160034);国家自然科学基金项目(编号: 31170206) |
|
摘要点击次数: 4220 |
全文下载次数: 2082 |
摘要: |
The First Discovery of a Cretaceous Cyatheaceae Trunk from China |
Songliao Basin is one of the largest, thickest and best preserved Cretaceous continental sedimentary basins in China. Palynological studies show that Cyathidites spores are common in the Cretaceous strata in the basin. As Cyatheaceae and Dicksoniaceae are spread in common by means of Cyathidites spores, the discovery of the Cyathidites spores is still considered to be an ambiguous evidence for the existence of Cyatheaceae plants, which hinders further precise analysis of paleoenvironment and paleoclimate in the basin. A series of Cretaceous Cyatheaceae stem fossils, found from Keshan County, Qiqihar City, Heilongjiang Province, provide solid evidence for the presence of Cyatheaceae tree fern in the Songliao Basin. The studied fossils are permineralized stem fragments of Cyatheaceae tree fern, and each piece consists of pith, dictyostele and cortex. Each meristele is S-, U- or W-shaped in transverse section, enclosed by a sclerenchyma sheath. Margins of the meristeles of the main dictyostelic ring curve deeply toward cortex or pith at the distal end of each leaf gap. Pith and cortex are parenchymatous, in which medullary bundles and roots are abundant. Wound tissues often occur in pith. This specimen is the first fossil record of Cyatheaceae trunk found in China, which suggests that ancestor taxa of the extant Cyatheaceae tree fern now living in tropical or subtropical region used to grow near Keshan County in northern Songliao Basin in Cretaceous. The present fossils and their associated petrified fossils of Tempskya and Bennettitales, may indicate that the paleoclimate there might have been tropical or subtropical. |
CHENG Ye-ming,LIU Feng-xiang.2017.The First Discovery of a Cretaceous Cyatheaceae Trunk from China[J].Acta Geoscientica Sinica,38(2):135-143. |
查看全文 查看/发表评论 下载PDF阅读器 |
|
|
|
|
|