Pollen cones and associated leaves from the Lower Cretaceous of China and a re-evaluation of Mesozoic male cycad cones
Pollen cones and associated leaves from the Lower Cretaceous of China and a re-evaluation of Mesozoic male cycad cones
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DOI：
10.1080/14772019.2013.819817
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发表时间：
2014-09
影响因子：
2.6
通讯作者：
S. Deng;J. Hilton;I. Glasspool;J. Dejax
中科院分区：
文献类型：
--
作者：
S. Deng;J. Hilton;I. Glasspool;J. Dejax
对采自海拉尔地区早白垩世的海拉尔粘松雄球花的角质层和花粉原位特征进行了重新研究。球果松散聚集，具有螺旋排列的盾形小孢子叶，含有树脂体。小孢子叶角质层厚，具乳突，椭圆形气孔，附属细胞6-9个，环绕细胞约10个。正面的孢子囊含有单槽的花粉，可归属于分散的分类群Cycadopites minimus。角质层和花粉都不同于Ixostrobus，但与苏铁属Androstrobus，Aegianthus，Loricanthus和假定的被子植物Solaranthus一致。对该属模式种的再分析。zamioides，提供了新的信息，其结构，并允许一个准确的属和改进的比较与其他属。一个新的属，Schimperstrobus，是为现在排除在Androstrobus之外的物种建立的。比较表明Solaranthus代表雄性苏铁锥体，Aegianthus，Loricanthus和Solaranthus是同义词; Aegianthus具有命名优先权。我们修订了Aegianthus sibiricus的属和种的组合诊断，以允许更多的物种被放置在属中，并建立了新的组合Aegianthus resinifera以前分配给Loricanthus的标本，Aegianthus daohugouensis以前放置在Solaranthus内的标本。海拉尔球果与Aegianthus属的界限一致，代表一个新种，我们将其命名为Aegianthus。Hailarensis comb. nov.与Aegianthus同属Aegianthus，并转移到Aegianthus phialophora comb. nov. hailarensis是银杏叶楔叶蕨（Sphenobaiera longifolia）的壳层，与A.海拉尔人然而，我们折扣，他们属于一个单一的植物物种，并得出结论，cuberous的一些中生代ginkgoalean和苏铁类群可能几乎无法区分。我们认为，Aegianthus在上侏罗世至下白垩世广泛分布于中国、蒙古和俄罗斯南部。
Male cones of Ixostrobus hailarensis from Lower Cretaceous strata of the Hailar region of north-east China were re-examined for features of their cuticle and in situ pollen. The cones are loosely aggregated and possess helically arranged peltate microsporophylls containing resin bodies. Microsporophyll cuticle is thick, papillate and has elliptical stomata with 6–9 subsidiary and ∼10 encircling cells. Adaxial sporangia contain monosulcate pollen assignable to the dispersed taxon Cycadopites minimus. Both the cuticle and pollen are distinct from Ixostrobus but are consistent with the cycad genera Androstrobus, Aegianthus, Loricanthus and the putative angiosperm Solaranthus. Reanalysis of the type species of Androstrobus, A. zamioides, provides new information on its structure and allows an accurate delimitation of the genus and improved comparison with other genera. A new genus, Schimperstrobus, is erected for species now excluded from Androstrobus. Comparisons indicate that Solaranthus represents a male cycad cone and that Aegianthus, Loricanthus and Solaranthus are synonyms; Aegianthus has nomenclatural priority. We emend the combined generic and specific diagnoses for Aegianthus sibiricus to allow additional species to be placed in the genus, and erect the new combinations Aegianthus resinifera for specimens previously assigned to Loricanthus, and Aegianthus daohugouensis for specimens previously placed within Solaranthus. The Hailar cone conforms to the generic circumscription of Aegianthus and represents a new species that we name A. hailarensis comb. nov. Androstrobus phialophora also conforms with Aegianthus and is transferred to Aegianthus phialophora comb. nov. Co-occurring with A. hailarensis are cuticles of the ginkgophyte leaf Sphenobaiera longifolia that are similar to microsporophyll cuticles of A. hailarensis. However, we discount that they belong to a single plant species and conclude that the cuticles of some Mesozoic ginkgoalean and cycadalean taxa may be virtually indistinguishable. We consider that Aegianthus was widespread across China, Mongolia and southern Russia during the Upper Jurassic to Lower Cretaceous.