Potomacanthus lobatus gen. et sp. nov., a new flower of probable Lauraceae from the Early Cretaceous (Early to Middle Albian) of eastern North America.
Potomacanthus lobatus gen. et sp. nov., a new flower of probable Lauraceae from the Early Cretaceous (Early to Middle Albian) of eastern North America.
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DOI：
10.3732/ajb.94.12.2041
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发表时间：
2007-12
影响因子：
3
通讯作者：
M. von Balthazar;K. Pedersen;P. Crane;M. Stampanoni;E. M. Friis
中科院分区：
文献类型：
--
作者：
M. von Balthazar;K. Pedersen;P. Crane;M. Stampanoni;E. M. Friis
一种炭化的化石花--龙须草。ET sp.Nov.，描述于美国弗吉尼亚州早白垩世(早-中白垩世)Puddledock地区。利用无损同步辐射X射线层析显微镜(SRXTM)对其内部花结构进行了研究。这种花是两性的，三分生的。花被片由两轮花被片组成。雄蕊群有两轮可育雄蕊。通过两个上部铰链裂片打开的花药。雌蕊群由单个心皮组成，花柱褶皱，子房囊状，包含单个下垂胚珠。该化石花与现存的樟科花有许多相似之处，不同于樟科其他科的花。然而，该化石花在细节上也不同于现存的所有樟科或化石，特别是雄蕊群的形态。这个新的分类单元，连同之前描述过的、但更零散的来自Puddledock地区的材料，提供了最早的植物化石记录，这些植物与樟科的亲缘关系比任何其他现存的科都要近。它揭示了几个衍生的形态特征，这些特征是现存樟科代表植物之间潜在的同构关系，并有助于提供越来越多的证据，证明在早白垩世结束之前，Laurales的早期多样化。
A charcoalified fossil flower, Potomacanthus lobatus gen. et sp. nov., is described from the Early Cretaceous (Early to Middle Albian) Puddledock locality, Virginia, USA. Internal floral structure was studied using nondestructive synchrotron-radiation x-ray tomographic microscopy (SRXTM). The flower is bisexual and trimerous. The perianth consists of two whorls of tepals. The androecium has two whorls of fertile stamens. Anthers open by two distally hinged valves. The gynoecium consists of a single carpel that is plicate in the style and ascidiate in the ovary and contains a single pendant ovule. The fossil flower shares many similarities with flowers of extant Lauraceae and is unlike flowers of other families of Laurales. However, the fossil flower also differs in detail from all extant or fossil Lauraceae, particularly in configuration of the androecium. The new taxon, together with previously described but more fragmentary material from the Puddledock locality, provides the earliest fossil record of plants more closely related to Lauraceae than to any other extant family. It reveals several derived morphological characters that are potential synapomorphies among extant representatives of the family Lauraceae and contributes to the growing evidence for an early diversification of Laurales before the end of the Early Cretaceous.