Department of Ecology and Evolutionary Biology, Natural History Museum and Biodiversity Institute, University of Kansas, Lawrence, Kansas 66045, USA.
Am J Bot. 2012 Sep;99(9):1531-40. doi: 10.3732/ajb.1200142. Epub 2012 Aug 24.
The glossopterids are a group of plants that thrived during a time of global warming similar to what is happening on the Earth today as well as the transition from archaic plant groups to the ancestors of modern groups. The diversity of the glossopterid clade is based on the megasporangiate structures assigned to the group, because the vegetative and pollen-bearing structures vary little. The presence of numerous reproductive genera from a single Upper Permian locality in the central Transantarctic Mountains provides important data on local glossopterid diversity in Antarctica.
Impression/compression fossils were imaged with a Leica 5000C digital camera on a dissecting microscope or a Fujifilm FinePix S1pro digital camera.
Two megasporangiate taxa are described: Scutum leiophyllum, which represents the first confirmed record of the genus in Antarctica, and Lidgettoniopsis ramulus, a new morphology consisting of a pinnate structure with oppositely attached megasporophylls. Plumsteadia ovata specimens indicate that this genus can be larger than previously recorded and illustrate the vegetative surface with a distinct midrib.
The presence of a laminar, multiovulate structure and a pinnate structure at the same site indicates that local-level glossopterid diversity in Antarctica is greater than previously hypothesized. The discovery of a new megasporophyll morphology in Antarctica (confirming the presence of three distinctive morphologies on the continent) shows that Antarctic glossopterid heterogeneity is on a par with other Gondwanan continents. The diversity of the Antarctic landscape reveals that high polar latitudes can sustain a diverse ecosystem during times of global warming.
舌羊齿植物群是一组在全球变暖时期繁盛的植物，类似于当今地球所经历的全球变暖以及从古老植物群到现代植物群祖先的过渡时期。舌羊齿植物群的多样性基于分配给该组的大孢子囊结构，因为营养和花粉结构变化不大。在南极洲中心的横贯南极山脉的单个上二叠统地点存在许多生殖属，为当地的南极舌羊齿多样性提供了重要数据。
在解剖显微镜上，使用徕卡 5000C 数码摄像头或富士 FinePix S1pro 数码摄像头对印痕/压印化石进行成像。
描述了两个大孢子囊分类群：Scutum leiophyllum，这是该属在南极洲的首次确认记录，以及 Lidgettoniopsis ramulus，这是一种新的形态，由具有相反附着的大孢子叶组成的羽状结构。Plumsteadia ovata 标本表明，该属可能比以前记录的更大，并说明具有明显中脉的营养表面。
同一地点存在层状、多胚珠结构和羽状结构表明，南极洲的局部水平舌羊齿多样性比以前假设的要大。在南极洲发现新的大孢子叶形态（确认该大陆存在三种独特形态）表明，南极舌羊齿植物的异质性与其他冈瓦纳大陆相当。南极景观的多样性表明，在全球变暖时期，高极纬度地区可以维持多样化的生态系统。
