Evaluating Relationships among Floating Aquatic Monocots: A New Species of Cobbania (Araceae) from the Upper Maastrichtian of South Dakota
Evaluating Relationships among Floating Aquatic Monocots: A New Species of Cobbania (Araceae) from the Upper Maastrichtian of South Dakota
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评估漂浮水生单子叶植物之间的关系：来自南达科他州上马斯特里赫特阶的柯巴尼亚（天南星科）新种
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Kirk R. Johnson
中科院分区：
文献类型：
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作者：
R. Stockey;G. Rothwell;Kirk R. Johnson
研究进展：在南达科他州上白垩统Hell Creek组的池塘沉积物中发现了大量浮游水生天南星科植物化石，为研究白垩统最上层的水生植被提供了宝贵的新资料，这些资料可用于描述Cobbania属的一个新种，并评价浮游水生单子叶植物之间的相关生殖结构和系统发育关系。 方法学：根据需要用细针揭开化石，以显示标本的表面特征。 用数字扫描相机捕获图像，并通过WinClada实施TNT进行系统发育分析。 新种Cobbania hickeyi Stockey，Rothwell &约翰逊将该属的分布范围扩展到白垩纪最上部，支持了Cobbania属的分类完整性，并增加了我们对该属内结构变异和物种丰富度的理解。相关的生殖结构包括一个天南星肉穗，加强分配Cobbania天南星科。系统发育分析，使用“全证据”的数据有助于解决相互矛盾的结果，无论是形态或核苷酸序列分析之间的关系浮动水生aroids，和化石分类Aquaephyllum不巢之间的其他浮动水生物种在我们的任何结果。结论：在晚白垩世，柯班亚属的物种是横跨北方的水生植被的重要组成部分。 在对Pistia stratiotes，Cobbania spp.，和种的天南星亚科浮萍亚科，从“全证据”分析的结果表明，专门为浮动水生生物形式可能压倒其他字符的形态分析结果。
Premise of research. A large number of floating aquatic aroid fossils have been recovered from pond sediments in the Hell Creek Formation (Upper Cretaceous) of South Dakota, providing valuable new data about aquatic vegetation of the uppermost Cretaceous, that are used to describe a new species of the genus Cobbania, and to evaluate associated reproductive structures and phylogenetic relationships among floating aquatic monocots. Methodology. Fossils were uncovered as needed with fine needles to reveal surface features of the specimens. Images were captured with a digital scanning camera, and phylogenetic analyses were conducted with TNT implemented through WinClada. Pivotal results. The new species, Cobbania hickeyi Stockey, Rothwell & Johnson, extends the range of the genus to the uppermost Cretaceous, supports the taxonomic integrity of the genus Cobbania, and increases our understanding of structural variation and species richness within the genus. Associated reproductive structures include an aroid spadix, strengthening the assignment of Cobbania to the Araceae. Phylogenetic analyses using “total-evidence” data help resolve conflicting results from either morphological or nucleotide sequence analyses of relationships among floating aquatic aroids, and the fossil taxon Aquaephyllum does not nest among the other floating aquatic species in any of our results. Conclusions. Species of the genus Cobbania were an important component of aquatic vegetation across the Northern Hemisphere during the Late Cretaceous. In tests of competing hypotheses for relationships among Pistia stratiotes, Cobbania spp., and species of Araceae subfamily Lemnoideae, the results from a “total-evidence” analysis suggest that specializations for the floating aquatic life form may be overwhelming other characters in the results of morphological analyses alone.