具彩色斑纹颅形贝在广西桂林下石炭统黄金组中的发现:兼论颅形贝属的地质地理分布  

Discovery of color patterned Cranaena(Brachiopoda) from the Lower Carboniferous Huangjin Formation in Guilin of Guangxi with a brief comment on its geological and geographic distribution

作　　者：陈智敏[1] 孙元林[1] 

机构地区：[1]造山带与地壳演化教育部重点实验室,北京大学地球与空间科学学院,北京100871

出　　处：《古地理学报》2013年第6期795-808,共14页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学基金项目(编号:41172001)资助

摘　　要：文中描述了产自广西桂林地区下石炭统黄金组下部的颅形贝属一新种,桂林颅形贝(Cranaena guilinensis)。新种以平直的前结合缘和背壳上发育中槽为特征。在4枚标本上发现保存有放射状的彩色条带,表明该种当时生活在温暖海域的浅水环境。对该属70个种的地质地理分布和生物多样性变化的初步分析表明,该属可能起源于早泥盆世欧美大陆西北缘的老世界区,之后的地理分布和生物多样性发展以北美地区为中心,经历了中泥盆世—晚泥盆世早期和早石炭世2次比较明显的辐射演化、迁移扩散高峰和晚泥盆世晚期的1次严重衰退。第1次高峰是中泥盆世—晚泥盆世早期,该属的生物多样性达到巅峰,生物地理分布范围扩大到欧美大陆之外的西伯利亚板块、哈萨克斯坦板块和华南板块等;第2次高峰是早石炭世,该属的生物多样性虽不及前一次,但获得了最广泛的地理分布,不仅在北方大陆有分布,而且已进入到冈瓦纳大陆边缘。晚泥盆世晚期该属的1次严重衰退显然与F/F灭绝事件有关。早石炭世之后,该属进入衰退阶段,最终在二叠纪初灭绝。Cranaena guilinensis is a new species of Cranaena from the lower part of the Huangjin Formation （Visean, Lower Carboniferous） of Guilin, Guangxi. It is characterized by a rectimarginate anterior commisure and a dorsal sulcus. Four specimens of this species show radiate color bands on shell surface, suggesting that it lived in a shallow water of warm marine realm. Preliminary study on the geolog- ical and geographic distribution and biodiversity pattern of 70 species of the genus indicates that this genus probably originated in area of the Old World Realm peripheral to the Euramerican Continent of the Early Devonian and experienced two times of radiation and dispersal during the Middle to early Late Devonian and Early Carboniferous, respectively, and a biodiversity crisis in the Famennian of Late Devonian. The genus reached to the zenith of its biodiversity during the Middle to early Late Devonian and its geographic distribution also expanded to plates of Siberia, Kasakstan and South China. Although the biodiversity of the genus in the Early Carboniferous is less than that in the Middle to early Late Devonian, the genus ob- tained the widest geographic distribution, not only in continents of North Hemisphere, but also in the pe- ripheral areas of the Gondwana Continent. The Famennian crisis is obviously related with the F/F mass ex- tinction event. After the Early Carboniferous the genus began to decline and was finally extincted in the beginning of Permian.

关 键 词：颅形贝属 腕足动物 彩色斑纹 黄金组 石炭纪 泥盆纪 生物地理 桂林 

分 类 号：Q915.5[天文地球—古生物学与地层学]