Early Middle Ordovician evidence for land plants in Argentina (eastern Gondwana)
Early Middle Ordovician evidence for land plants in Argentina (eastern Gondwana)
复制标题
DOI：
10.1111/j.1469-8137.2010.03433.x
复制
发表时间：
2010-01-01
期刊：
影响因子：
9.4
通讯作者：
Steemans, P.
中科院分区：
文献类型：
--
作者：
Rubinstein, C. V.;Gerrienne, P.;Steemans, P.
胚胎植物（陆地植物）的出现是地球历史上最重要的进化突破之一。它在全球范围内不可逆转地改变了气候和生物地球化学过程；它允许所有真核陆地生物进化并入侵几乎所有的大陆环境。在此工作之前，最早明确的胚胎痕迹是来自沙特阿拉伯和捷克共和国（冈瓦纳西部）的Darriwilian（中奥陶世晚期；约4.63 - 4.61亿年前）隐孢子。本文对阿根廷（Gondwana东部）大坪期（中奥陶世早期，约473-471 Ma）孢粉样品进行了研究。我们发现了一个多样的隐孢子组合，包括裸露的和包膜封闭的单孢子体和四孢子体，代表5个属。我们的发现强化了早期的观点，即胚胎最早是在冈瓦纳进化的。这表明植物的陆地化可能是从冈瓦纳东部开始的。大坪期组合的多样性表明胚胎植物的起源更早，早奥陶世甚至寒武纪。大平纪和Aeronian（早志留世）隐孢子组合相似，表明胚胎体在其多样化的第一个c. 35-45万年的进化速度非常缓慢。阿根廷的隐孢子比其他隐孢子的出现早了大约800万到1200万年，是目前陆地上最早的植物证据。
P>The advent of embryophytes (land plants) is among the most important evolutionary breakthroughs in Earth history. It irreversibly changed climates and biogeochemical processes on a global scale; it allowed all eukaryotic terrestrial life to evolve and to invade nearly all continental environments. Before this work, the earliest unequivocal embryophyte traces were late Darriwilian (late Middle Ordovician; c. 463-461 million yr ago (Ma)) cryptospores from Saudi Arabia and from the Czech Republic (western Gondwana).Here, we processed Dapingian (early Middle Ordovician, c. 473-471 Ma) palynological samples from Argentina (eastern Gondwana).We discovered a diverse cryptospore assemblage, including naked and envelope-enclosed monads and tetrads, representing five genera.Our discovery reinforces the earlier suggestion that embryophytes first evolved in Gondwana. It indicates that the terrestrialization of plants might have begun in the eastern part of Gondwana. The diversity of the Dapingian assemblage implies an earlier, Early Ordovician or even Cambrian, origin of embryophytes. Dapingian to Aeronian (Early Silurian) cryptospore assemblages are similar, suggesting that the rate of embryophyte evolution was extremely slow during the first c. 35-45 million yr of their diversification. The Argentinean cryptospores predate other cryptospore occurrences by c. 8-12 million yr, and are currently the earliest evidence of plants on land.