Whole-Plant Reconstruction and Phylogenetic Relationships of Elatides zhoui sp. nov. (Cupressaceae) from the Early Cretaceous of Mongolia
Whole-Plant Reconstruction and Phylogenetic Relationships of Elatides zhoui sp. nov. (Cupressaceae) from the Early Cretaceous of Mongolia
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DOI：
10.1086/677651
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发表时间：
2014-09
影响因子：
2.3
通讯作者：
G. Shi;A. Leslie;P. Herendeen;N. Ichinnorov;Masamichi Takahashi;Patrick Knopf;P. Crane
中科院分区：
文献类型：
--
作者：
G. Shi;A. Leslie;P. Herendeen;N. Ichinnorov;Masamichi Takahashi;Patrick Knopf;P. Crane
研究的优先权。蒙古早白垩世保存异常完好的木化石包括丰富的针叶树多叶枝，其上附着有花粉球和种子球。基于这些化石的全株重建，使这种灭绝的植物与现存的针叶树的关系的关键评估。方法论从Tugrug褐煤矿收集的大量褐煤样品在水中分解，用盐酸和氢氟酸清洗，洗涤，并在空气中干燥。然后使用光学和扫描电子显微镜检查化石。初步结果。摘要周氏弹性虫Elatides zhoui sp. nov.叶螺旋排列，主要分布在叶的近轴面，具两条狭窄的气孔带。雄球花通常以紧密的螺旋状侧向着生在芽上;每个小孢子叶有三个花粉囊，产生带有小圆孔的非囊状花粉。球果有许多苞片鳞片复合体，每一个都有一个小的膜质胚珠鳞片和4到6颗种子。在所有已描述的Elatides种中，对Elatides zhoui的了解最全面，种子球和花粉球形态的主要特征表明它与现存的Cunninghamia最密切相关，而Cunninghamia今天有两个仅限于东亚的种。形态学分支分析采用简约法解决了一个扩大Cunninghamioideae分支，其中包括现存的Cunninghamia，E。Zhoui和其他Cunninghamia类化石，是所有其他现存Cupressaceae sensu lato的姐妹群。结论.周氏长枝树的发现进一步证明了广义柏科在白垩纪的多样性，并支持了在柏科早期演化过程中，尤其是杉木类针叶树的多样性和广泛分布的假说。
Premise of research. Exceptionally well-preserved lignified fossils from the Early Cretaceous of Mongolia include abundant conifer leafy shoots with attached pollen cones and seed cones. A whole-plant reconstruction based on these fossils enables a critical evaluation of the relationship of this extinct plant with extant conifers. Methodology. Bulk lignite samples collected from the Tugrug lignite mine were disaggregated in water, cleaned with hydrochloric and hydrofluoric acids, washed, and dried in air. Fossils were then examined using light and scanning electron microscopy. Pivotal results. Elatides zhoui sp. nov. has helically arranged leaves with two narrow lateral stomatal bands, predominantly on the adaxial leaf surface. Pollen cones are usually borne laterally on shoots in tight spirals; each microsporophyll bears three pollen sacs that produce nonsaccate pollen with a small circular aperture. Seed cones have numerous bract-scale complexes, each with a small membranous ovuliferous scale and four to six seeds. Elatides zhoui is the most completely understood of all described Elatides species, and major features of seed cone and pollen cone morphology indicate that it is most closely related to extant Cunninghamia, which today has two species restricted to East Asia. Morphological cladistic analyses using parsimony resolved an expanded Cunninghamioideae clade, which includes extant Cunninghamia, E. zhoui, and other Cunninghamia-like fossils, as the sister group to all other extant Cupressaceae sensu lato. Conclusions. Elatides zhoui provides further evidence for the diversity of Cupressaceae sensu lato during the Cretaceous and supports the hypothesis that cunninghamioid conifers in particular were diverse and widespread during the early evolution of the Cupressaceae.