Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, UK.
Zurich Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, CH-8057, Zurich, Switzerland.
Am J Bot. 2018 Jan;105(1):95-107. doi: 10.1002/ajb2.1009. Epub 2018 Feb 12.
Fossils provide minimum age estimates for extant lineages. Here we critically evaluate Cantisolanum daturoides Reid & Chandler and two other early putative seed fossils of Solanaceae, an economically important plant family in the Asteridae.
Three earliest seed fossil taxa of Solanaceae from the London Clay Formation (Cantisolanum daturoides) and the Poole and Branksome Sand Formations (Solanum arnense Chandler and Solanispermum reniforme Chandler) were studied using x-ray microcomputed tomography (MCT) and scanning electron microscopy (SEM).
The MCT scans of Cantisolanum daturoides revealed a high level of pyrite preservation at the cellular level. Cantisolanum daturoides can be clearly excluded from Solanaceae and has more affinities to the commelinid monocots based on a straight longitudinal axis, a prominent single layer of relatively thin-walled cells in the testa, and a clearly differentiated micropyle surrounded by radially elongated and inwardly curved testal cells. While the MCT scans show no internal preservation in Solanum arnense and Solanispermum reniforme, SEM images show the presence of several characteristics that allow the placement of these taxa at the stem node of Solanaceae.
Cantisolanum daturoides is likely a member of commelinid monocots and not Solanaceae as previously suggested. The earliest fossil record of Solanaceae is revised to consist of fruit fossil with inflated calyces from the early Eocene of Patagonia (52 Ma) and fossilized seeds from the early to mid-Eocene of Europe (48-46 Ma). The new identity for Cantisolanum daturoides does not alter a late Cretaceous minimum age for commelinids.
化石为现存谱系提供了最小年龄估计。在这里，我们批判性地评估了 Cantisolanum daturoides Reid & Chandler 和另外两个茄科的早期假定种子化石，茄科是菊科中一个具有重要经济意义的植物科。
使用 X 射线微计算机断层扫描 (MCT) 和扫描电子显微镜 (SEM) 研究了伦敦粘土形成期的三个最早的茄科种子化石种（Cantisolanum daturoides）和普尔和布兰克斯姆砂形成期的（Solanum arnense Chandler 和 Solanispermum reniforme Chandler）。
Cantisolanum daturoides 的 MCT 扫描显示细胞水平上保存了高水平的黄铁矿。Cantisolanum daturoides 显然不能归入茄科，而是与鸭跖草科单子叶植物的亲缘关系更近，这是基于其直的纵轴、种皮中单层相对较薄的细胞和明显分化的具辐射状伸长和向内弯曲的种皮细胞的珠孔。虽然 MCT 扫描显示 Solanum arnense 和 Solanispermum reniforme 内部没有保存，但 SEM 图像显示出存在几种特征，这些特征允许将这些类群置于茄科的茎节点上。
Cantisolanum daturoides 可能是鸭跖草科单子叶植物的成员，而不是以前认为的茄科。茄科的最早化石记录被修订为包括来自巴塔哥尼亚早始新世（52 Ma）的膨果化石和来自欧洲早至中始新世（48-46 Ma）的化石种子。Cantisolanum daturoides 的新身份并没有改变鸭跖草科的晚白垩纪最小年龄。
