Data from: Two new species of Nilssoniopteris (Bennettitales) from the Middle Jurassic of Sandaoling, Turpan-Hami Basin, Xinjiang, NW China

Two new species of Nilssoniopteris of the order Bennettitales, Nilssoniopteris hamiensis Zhao and Deng, new species and Nilssoniopteris crassiaxis Zhao and Deng, new species, are established from the Xishanyao Formation (Middle Jurassic) of Sandaoling Coal Mine in Hami, Xinjiang, China, based on leaf macromorphology and cuticular features. N. hamiensis is characterized by its varied leaf shapes and trichome bases of 1–4 cells on the abaxial epidermis, while N. crassiaxis is characterized by its broad midrib (especially near the leaf base) and trichome bases of 1–3 cells on the abaxial epidermis. Both species possess unique venation patterns that are not only simple and free, but also forked and merged to form closed loops. These anastomosing veins are even more complicated in N. crassiaxis in that the veins can fork once, twice, or even three times, the forked veins can later merge with each other or with an adjacent vein to form a closed loop, which may later further disjoin. The generic diagnosis of Nilssoniopteris is thus accordingly emended, particularly in the venation pattern. In addition, the stratigraphic and geographical distributions of all 45 Jurassic Nilssoniopteris species worldwide have been summarized and analyzed to better understand their brief evolutionary history, indicating that Nilssoniopteris might be able to grow not only in subtropical regions as the living cycads are but also in warm climatic regions.基于叶片宏观形态与表皮构造，研究于中国新疆哈密三道岭煤矿的中侏罗世西山窑组（Xishanyao Formation）中建立了本内苏铁目（Bennettitales）尼尔桑羽叶属（Nilssoniopteris）的两个新种：哈密尼尔桑羽叶（Nilssoniopteris hamiensis Zhao et Deng, sp. nov.）与粗轴尼尔桑羽叶（Nilssoniopteris crassiaxis Zhao et Deng, sp. nov.）。哈密尼尔桑羽叶以叶形多样、下表皮具1~4个细胞的毛基部为典型特征；粗轴尼尔桑羽叶则以宽中脉（尤其靠近叶基处）、下表皮具1~3个细胞的毛基部为主要识别特征。两个新种均具有独特的脉序模式：既存在简单分离的叶脉，也存在分叉并融合形成闭合环的脉序。其中粗轴尼尔桑羽叶的吻合脉更为复杂：叶脉可进行一次、两次甚至三次分叉，分叉后的叶脉可相互融合或与相邻叶脉结合形成闭合环，后续还可再次解离。据此，尼尔桑羽叶属的属征得到了修订，尤以脉序特征的修订最为显著。此外，本文总结并分析了全球范围内已报道的45种侏罗纪尼尔桑羽叶属植物的地层与地理分布，以明晰其简要演化历程，研究结果显示：尼尔桑羽叶属不仅可如现生苏铁类植物般生长于亚热带区域，还可适应温暖气候区的生境。