Cuticular anatomy of Comia(Pteridospermae) from the Upper Permian of Yumen in Gansu Province, Northwestern China, and palaeoatmospheric CO_2 reconstruction  

作　　者：DONG Chong XU XiaoHui WANG QiuJun MA FuJun YANG Yi DAO KeQun SUN BaiNian SUN KeQin 

机构地区：[1]School of Earth Sciences and Key Laboratory of Mineral Resources in Western China,Lanzhou University [2]School of Earth Sciences and Resources,China University of Geosciences

出　　处：《科学通报》2013年第S1期185-192,共8页Chinese Science Bulletin

基　　金：supported by the National Basic Research Program of China(2012CB822003);the National Natural Science Foundation of China(41172022);Specialized Research Fund for the Doctoral Program of Higher Education(20120211110022)

摘　　要：Comia macrofossils have been widely known from rocks of the Late Permian age in the Angaran and Cathaysian Palaeobiogeographic regions. However, the epidermal structure of the genus has not been reported. The new material with wellpreserved cuticles obtained from the Late Permian Sunan Formation in the west of Gansu Province, Northwestern China allows a new species to be attributed to this genus, namely Comia dashankouensis Dong C et Sun BN sp. nov. The cuticular features of the genus are described, including the general structures of lower and upper cuticles, stomata, and papillae. The stomatal density(SD) and stomatal index(SI) of fossil cuticles are routinely used today as a proxy in the reconstruction of palaeoatmospheric CO2 levels for the Cenezoic, Mesozoic, and Paleozoic eras. In particular, the cuticles of cycads, ginkgoes, conifers, and pteridosperms have frequently been used for this purpose. Within this study, the CO2 concentration of the early Late Permian was reconstructed by performing stomatal frequency analysis of these Comia fossils, suggesting a maximum palaeoatmospheric CO2 concentration of 1929.5 ppmv, consistent with the estimates obtained using GEOCARB III, and a minimum of 1157.8 ppmv, consistent with the estimates obtained using GEOCARB II.Comia macrofossils have been widely known from rocks of the Late Permian age in the Angaran and Cathaysian Palaeobiogeographic regions. However, the epidermal structure of the genus has not been reported. The new material with wellpreserved cuticles obtained from the Late Permian Sunan Formation in the west of Gansu Province, Northwestern China allows a new species to be attributed to this genus, namely Comia dashankouensis Dong C et Sun BN sp. nov. The cuticular features of the genus are described, including the general structures of lower and upper cuticles, stomata, and papillae. The stomatal density(SD) and stomatal index(SI) of fossil cuticles are routinely used today as a proxy in the reconstruction of palaeoatmospheric CO2 levels for the Cenezoic, Mesozoic, and Paleozoic eras. In particular, the cuticles of cycads, ginkgoes, conifers, and pteridosperms have frequently been used for this purpose. Within this study, the CO2 concentration of the early Late Permian was reconstructed by performing stomatal frequency analysis of these Comia fossils, suggesting a maximum palaeoatmospheric CO2 concentration of 1929.5 ppmv, consistent with the estimates obtained using GEOCARB III, and a minimum of 1157.8 ppmv, consistent with the estimates obtained using GEOCARB II.

关 键 词：LATE PERMIAN Comia cuticle STOMATAL PARAMETER palaeoatmospheric CO2 

分 类 号：Q914[天文地球—古生物学与地层学]