Skog Judith E, Sender Luis Miguel
Department of Biology, George Mason University, Fairfax, Virginia, 22030, USA.
Fundación Conjunto Paleontológico de Teruel-Dinópolis/Museo Aragonés de Paleontología, Avenida Sagunto s/n, Teruel, 44002, Spain.
Am J Bot. 2022 Sep;109(9):1443-1455. doi: 10.1002/ajb2.16050. Epub 2022 Sep 22.
Reinvestigation of previously described fossil plants using improved techniques can provide insights for additional characters resulting in better family assignments and relationships to modern plants, as in this new study of the fossil fern Acrostichopteris from the mid-Cretaceous. The discovery of new species within genera provides additional characteristics for comparisons and support for family assignments.
Fossil material was uncovered from the matrix (degagement) for the specimens described here. Material was removed from the matrix and mounted for examination by scanning electron microscopy (SEM). Spores were extracted and prepared for examination with light, fluorescence, and SEM. Characters for the previously described material from the Potomac Group in the USA and the new material from Spain were compared with those of other fossils assigned to the genus.
The genus, described by Fontaine in 1889, reexamined by Berry in 1911, and assigned to the Schizaeaceae by Reed in 1947, is reassigned to the family Hymenophyllaceae on the basis of characteristics of the pinnules, sori, sporangia, and spores. We describe a new species in the genus from the Lower Cretaceous (Albian) of Spain that most likely belongs in this family, based on characteristics of the pinnules and the sori. A summary of all the species previously assigned to the genus is included.
Assignment of this fossil to the family Hymenophyllaceae is based on all characters known and comparison to modern species, provides the time for appearance of characteristics within the family, and indicates diversification of Hymenophyllum species in the mid-Cretaceous.
利用改进技术对先前描述的化石植物进行重新研究，能够为更多特征提供见解，从而实现更准确的科属划分以及与现代植物关系的确定，就像对白垩纪中期的化石蕨类植物尖叶蕨（Acrostichopteris）的这项新研究一样。属内新物种的发现为比较提供了更多特征，并支持科属划分。
从基质中挖掘出此处所描述标本的化石材料（分离）。将材料从基质中取出并安装好，以便通过扫描电子显微镜（SEM）进行检查。提取孢子并准备用光镜、荧光显微镜和扫描电子显微镜进行检查。将美国波托马克组先前描述材料的特征以及来自西班牙的新材料的特征与归入该属的其他化石的特征进行比较。
该属由方丹于1889年描述，贝里于1911年重新研究，里德于1947年将其归入莎草蕨科，现根据羽片、孢子囊群、孢子囊和孢子的特征重新归入膜蕨科。基于羽片和孢子囊群的特征，我们描述了一种来自西班牙下白垩统（阿尔布阶）的该属新物种，它很可能属于这个科。文中还包括了先前归入该属的所有物种的概述。
将这种化石归入膜蕨科是基于所有已知特征并与现代物种进行比较得出的，确定了该科内特征出现的时间，并表明膜蕨属物种在白垩纪中期已经多样化。
