Riccardiothallus devonicus gen. et sp nov., the earliest simple thalloid liverwort from the Lower Devonian of Yunnan, China
Riccardiothallus devonicus gen. et sp nov., the earliest simple thalloid liverwort from the Lower Devonian of Yunnan, China
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DOI：
10.1016/j.revpalbo.2012.03.012
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发表时间：
2012-06-01
影响因子：
1.9
通讯作者：
Li, Cheng-Sen
中科院分区：
文献类型：
--
作者：
Guo, Cai-Qing;Edwards, Dianne;Li, Cheng-Sen
本文描述了云南下泥盆统(普拉吉统)坡松冲组中的一种苔类化石，该化石被保存为灰色砂质泥岩中的部分过矿化挤压。该植物由一个规则分叉的平坦生态状态的多层叶状体组成，边缘完整。通过与现存苔类配子体和化石地钱配子体的比较，在菊科(Jungermanniopsida)中建立了一个新属。这块化石看起来与现存的里卡迪亚属的几个成员非常相似，是最早的明确的苔类巨型化石证据。根据该种的沉积环境和现存的许多种的栖息地，推测该种可能生活在温暖潮湿的河水环境中。迪翁立克次体的年龄(普拉吉亚，407-411 Ma)表明，Jungermanniopsida和Metzgeriidae的分化发生在泥盆纪早期，明显早于现代苔类叶绿体DNA序列分析和现有全部证据的系统发育(晚泥盆世，359-385 Ma：晚石炭世，299-307 Ma)。(C)2012爱思唯尔B.V.保留所有权利。
This paper describes a fossil liverwort in the Posongchong Formation, Lower Devonian (Pragian), Yunnan, China preserved as a partially permineralized compression in gray arenaceous mudstone. The plant comprises a regularly-bifurcating flat ecostate multilayered thallus with entire margins. Following comparisons of this fossil with gametophytes of extant and fossil liverworts, a new genus Riccardiothallus was established in the family Aneuraceae (Jungermanniopsida). The fossil, which appears to be closely similar to several members of the extant genus Riccardia, is the earliest unequivocal megafossil evidence of a liverwort. Considering the sedimentary environment of Riccardiothallus devonicus and the habitats of many extant Riccardia species, we conclude that Riccardiothallus devonicus probably lived in a warm and humid riverine environment. The age (Pragian, 407-411 Ma) of Riccardiothallus devonicus suggests that the differentiation of Jungermanniopsida and Metzgeriidae was in the Early Devonian, significantly earlier than the assumptions derived from analyses of chloroplast DNA sequences of modern liverworts and current total evidence phylogenies (Late Devonian, 359-385 Ma: Late Carboniferous, 299-307 Ma). (C) 2012 Elsevier B.V. All rights reserved.