Exceptionally well-preserved Early Cretaceous leaves of Nilssoniopteris from central Mongolia
Exceptionally well-preserved Early Cretaceous leaves of Nilssoniopteris from central Mongolia
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DOI：
10.2478/acpa-2018-0016
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发表时间：
2018-12
影响因子：
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通讯作者：
Fabiany Herrera;G. Shi;G. Tsolmon;N. Ichinnorov;Masamichi Takahashi;P. Crane;P. Herendeen
中科院分区：
文献类型：
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作者：
Fabiany Herrera;G. Shi;G. Tsolmon;N. Ichinnorov;Masamichi Takahashi;P. Crane;P. Herendeen
摘要描述了蒙古中部早白垩世（Aptian-Albian）两个新的本内蒂塔类叶化石种，并将其归属于Nilssoniopteris属。Nilssoniopteris tomentosa F.Herrera，G.Shi，Tsolmon，Ichinnorov，Takahashi，P.R.起重机，et Herend.新种，分离自Tevshiingovi组的Tevshiingovi露天煤矿中收集的大量沉积物样品中的中化石，其特征在于具有由在叶背面上的分枝的扁平的多细胞毛状体组成的致密的、发育良好的毛被。本种提供了第一个直接的证据，复杂的多细胞毛在Bennettitales和增加的证据叶解剖特征的组，可能有利于提高水分利用效率和/或可能有其他功能，如阻止昆虫植食性。与其它保存较好的斑叶蕨目植物（Nilssoniopteris shiveovoensis F.Herrera，G.Shi，Tsolmon，Ichinnorov，Takahashi，P.R.起重机，et Herend.）新种，从Shivee Ovoo地区的Khukhteeg组采集的手标本表明，bennettitalean叶的远轴角质层上常见的毛状体基部具有非常低的毛状体化潜力。在某些情况下，这些毛状体可能是随着叶子成熟而脱落的，但在其他情况下，它们可能在成岩作用期间腐烂，或者在制备化石叶子的标准过程中被破坏。
Abstract Two new Early Cretaceous (Aptian-Albian) species of fossil bennettitalean leaves are described from central Mongolia and assigned to the genus Nilssoniopteris. Nilssoniopteris tomentosa F.Herrera, G.Shi, Tsolmon, Ichinnorov, Takahashi, P.R.Crane, et Herend. sp. nov., isolated from bulk sediment samples collected for mesofossils in the Tevshiingovi Formation at the Tevshiin Govi opencast coal mine, is distinctive in having a dense, well-developed indumentum composed of branched, flattened multicellular trichomes on the abaxial leaf surface. This species provides the first direct evidence of complex multicellular trichomes in Bennettitales and adds to the evidence of leaf anatomical features in the group that were probably advantageous in increasing water use efficiency and/or perhaps had other functions such as deterring insect herbivory. Comparison with other well-preserved leaves of Bennettitales, including Nilssoniopteris shiveeovoensis F.Herrera, G.Shi, Tsolmon, Ichinnorov, Takahashi, P.R.Crane, et Herend. sp. nov., collected as hand specimens from the Khukhteeg Formation at the Shivee Ovoo locality, suggests that the trichome bases seen commonly on the abaxial cuticle of bennettitalean leaves bore trichomes with very low fossilization potential. In some cases these trichomes may have been shed as the leaves matured, but in other cases they probably decayed during diagenesis or were destroyed during the standard processes by which fossil leaf cuticles are prepared.