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肋木是欧亚大陆早一中三叠世最标志的一属植物,在华南以往的地质文献中尚未报道过。本文描述了首次发现于桑植县一带中三叠世巴东组下段的一种肋木化石即湖南肋木(新种)。根据这个种的孢子囊近似凹入的盘形等特征,认为它是一种适应在水体中漂浮的滨海潮坪植物。此外,文中对肋木的地质、地理分布也作了较系统的总结,并提出其确切的地质时限为印度期一安尼期的看法。 相似文献
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R. L. Dunstone 《Australian Journal of Earth Sciences》2019,66(1):57-70
Devonian fossil localities are summarised for coastal southeastern Australia, including both marine invertebrates representing a major late Frasnian (Late Devonian) transgression, and plant remains of Middle–Late Devonian age in associated non-marine strata. Lycopsid plant specimens (Leptophloeum) from near Majors Creek, NSW, first documented by Edgeworth David and E. F. Pittman in association with marine fossils to demonstrate a Late Devonian age, are illustrated for the first time. Lycopsid plants of presumed Middle Devonian age are illustrated from three new localities: Yowrie River inland from Cape Dromedary, Tuross River northwest of Narooma and Charlies Forest Road northeast of Braidwood. The Yowrie River occurrence (in float) indicates probable Middle Devonian strata upstream that are not shown on published maps. The Tuross River occurrence is in sheared and folded strata previously mapped as Ordovician, and the Braidwood occurrence demonstrates Devonian black shales adjacent to previously mapped Ordovician. Evidence supporting alternative thrust or simple fold interpretations for the Budawang Synclinorium is discussed, and relevant Ordovician fossil localities are listed. 相似文献
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林家组出露于辽宁东部本溪林家崴子一带.自小林贞一1942年记载以来,其时代一直有很大的争议.争议跨度从第三系到上二叠统.20世纪80年代初,张武等依据动植物化石和地层对比,提出了林家组属于中三叠世的观点.由于林家组产出的植物化石十分复杂,既有古生代,又有中生代分子,且没有锆石年龄证据,故林家组时代仍然存疑.近年来,在林家组底部找到了变质凝灰质粉砂岩,其中有很多锆石.根据30颗保存较好锆石测年结果,发现4颗最年轻锆石的206Pb/238U平均年龄是239.5±4.1 Ma.另外,最近前甸子地区林家组发现了少林肋木（Pleuromeia shaolinii）.因此尽管林家植物群存在二叠纪和三叠纪均有分布的重要植物,但结合锆石定年、地层对比、岩性特征、平行不整合接触关系、三叠纪代表植物及中三叠世到早白垩世均有分布的昆虫索德蠊属来综合分析,可以确认林家组确实属于中三叠世. 相似文献
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HAO Shougang WANG Deming WANG Qi XUE Jinzhuang 《《地质学报》英文版》2006,80(1):11-19
A new plant, Zhenglia radiata gen. et sp. nov., from the Posongchong Formation （Early Devonian, Pragian age） of the Wenshan District of southeastern Yunnan Province, China is a small herbaceous lycopsid. The aerial branches divide into foliar and fertile stems. The arrangement of the leaf bases on the stem shows lepidodendroid-like phyllotaxy. Possibly the leaf base bears a ligulate pit. The microphyll consists of a swollen, decurrent base, and an entire, linear lamina. The fertile axis is composed of sporophylls arranged helically, forming a compact area similar to cone-like structure. Each sporophyll consists of a widened lateral extension and a distal lamina. The ovoid-elongate sporangia are attached adaxially on the surface of sporophylls. Based on morphological similarities, especially the undivided microphylls, the style of phyllotaxy, the form of the cone-like structures and sporangia, the new lycopsid Zhenglia radiata is placed in the order Protolepidodendrales and a possible evolutionary relationship with the arborescent lycopsids of the Late Devonian and Carboniferous is considered. 相似文献
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XUE Jinzhuang 《《地质学报》英文版》2011,85(3):569-580
To investigate the phylogeny of early lycopsids, cladistic analyses using both parsimony and Bayesian approaches are presented, with a data matrix of 33 morphological characters across 25 taxa. The resulting parsimony and Bayesian trees showed overall similarities in tree topologies. In the Bayesian tree, the Protolepidodendrales and the heterosporous lycopsids are recognized as two monophyletic groups, and within the latter group, the Isoetales sensu lato forms a subclade. This topology implies that the acquisition of a ligulate character evolved twice in the lycopsids, once in the protolepidodendralean Leclercqia Banks et al., and once in the heterosporous lycopsid clade. Phylogenetic positions of several lycopsid plants previously reported from the Mid-Upper Devonian of South China, which have uncertain ordinal affinities, were estimated by the cladistic analyses; cf. Longostachys Xue et Hao, Longostachys Zhu et al., Monilistrobus Wang et Berry, and Yuguangia Hao et al. fall well within the Isoetales clade, as earliest members of this order, while Minostrobus Wang and Wuxia Berry et al. are nested within the basal part of the heterosporous lycopsids. Bayesian analyses are a very useful approach in systematic studies and can be applied in analyzing paleobotanical data sets as well. 相似文献
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林家组出露于辽宁东部本溪林家崴子一带.自小林贞一1942年记载以来，其时代一直有很大的争议.争议跨度从第三系到上二叠统.20世纪80年代初，张武等依据动植物化石和地层对比，提出了林家组属于中三叠世的观点.由于林家组产出的植物化石十分复杂，既有古生代，又有中生代分子，且没有锆石年龄证据，故林家组时代仍然存疑.近年来，在林家组底部找到了变质凝灰质粉砂岩，其中有很多锆石.根据30颗保存较好锆石测年结果，发现4颗最年轻锆石的206Pb/238U平均年龄是239.5±4.1 Ma.另外，最近前甸子地区林家组发现了少林肋木（Pleuromeia shaolinii）.因此尽管林家植物群存在二叠纪和三叠纪均有分布的重要植物，但结合锆石定年、地层对比、岩性特征、平行不整合接触关系、三叠纪代表植物及中三叠世到早白垩世均有分布的昆虫索德蠊属来综合分析，可以确认林家组确实属于中三叠世. 相似文献
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本文首次对早三叠世特征化石美丽肋木的原位大孢子进行D-、L-氨基酸对映体分析。其初步结果在D-型氨基酸异构体特征、氨基酸总量与现代石松大孢子的氨基酸组成方面一定的系统学关系：两者在氨基酸H值方面明显的区别可能系化石石松的埋藏环境的后生原因造成的。 相似文献
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肋木属（Ｐｌｅｕｒｏｍｅｉａ）是三叠纪早、中期最重要的石松植物之一。文中描述了长江流域中三叠世肋木属化石２个种,查明了安尼期早期它们在本区几乎是同时出现的,此后期分布区由东向西逐渐缩小,植物分布区缩小的原因很可能与当时海平面升降有关。依据肋木属的产出层位和共存的海相化石认为,肋木属的地质时限为印度期—安尼期,安尼期末为全球肋木属生命危机期。从生物演化和演变过程中的质变标志出发,建立和完善了水韭目分类系统,水韭目包括肋木科和水韭科,前科包括肋木属和古水韭属,后科包括脊囊属、斯基林孢穗属和水韭属。 相似文献
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