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首页> 外文期刊>Journal of Systematic Palaeontology >Pollen cones and associated leaves from the Lower Cretaceous of China and a re-evaluation of Mesozoic male cycad cones
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Pollen cones and associated leaves from the Lower Cretaceous of China and a re-evaluation of Mesozoic male cycad cones

机译：中国下白垩统的花粉锥及相关叶片和中生代苏铁圆锥体的重新评价

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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.
机译：重新检查了中国东北海拉尔地区下白垩统海拉氏x的雄性锥体的表皮和原位花粉特征。锥体疏松地聚集，并具有螺旋状排列的包含树脂体的叶状微孢子囊。小孢子囊的表皮厚，具乳突，有椭圆形的气孔，有6-9个副生和〜10个周围的细胞。近端孢子囊含有单硫酸盐花粉，可分配给分散的分类单元小苏铁。角质层和花粉均与I属植物不同，但与苏铁属属的Androstrobus，Aegianthus，Loricanthus和假定的被子植物Solaranthus一致。重新分析雄蕊座果蝇的类型种，为其结构提供了新的信息，并允许该属的准确定界并改善与其他属的比较。为现在被排除在Androstrobus之外的物种建立了一个新的属Schimperstrobus。比较表明，虎耳草表示雄性苏铁圆锥体，而神藤，罗勒坎hu斯和虎耳草是同义词。 eg草具有命名优先权。我们改进了对刺五加的综合诊断和特殊诊断，以允许将其他物种放入该属中，并为先前分配给Loricanthus的标本建立了新的Aegianthus resinifera组合，而对于先前放入了太阳花的标本建立了新的Aegianthus daohugouensis。海拉尔锥符合神仙属的一般界限，代表一种新物种，我们将其命名为海拉尔A. hailarensis梳。十一月孔雀藻也与凤尾鱼相符，并转移到凤尾草梳中。十一月银杏植物叶片Sphenobaiera longifolia的角质层与A. hailarensis同时出现，类似于A. hailarensis的微孢子体角质层。但是，我们认为它们属于单一植物物种，并得出结论，某些中生代金格莱恩和cydaledalean类群的表皮实际上是无法区分的。我们认为，在上侏罗纪至下白垩纪期间，神龙属分布在中国，蒙古和俄罗斯南部。

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