Conifer wood assemblage dominated by Podocarpaceae, early Eocene of Laguna del Hunco, central Argentinean Patagonia
Conifer wood assemblage dominated by Podocarpaceae, early Eocene of Laguna del Hunco, central Argentinean Patagonia
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DOI：
10.3897/phytokeys.156.54175
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发表时间：
2020-08
期刊：
影响因子：
1.4
通讯作者：
Roberto R. Pujana;P. Wilf;M. Gandolfo
中科院分区：
文献类型：
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作者：
Roberto R. Pujana;P. Wilf;M. Gandolfo
在始新世早期，巴塔哥尼亚具有高度多样化的植物区系，主要是通过压缩和花粉化石来了解的。这一时期的化石木材研究在该地区很少，而且在拉古纳德尔亨科植物群中基本上没有，该植物群具有高度多样化和保存完好的压缩组合。本文对巴塔哥尼亚中西部汉科湖（Laguna del Hunco）化石湖床（始新世早期，约52 Ma）的26株针叶林进行了研究，其中12株属。优势种为南极Phyllocladoxylon，与早分化的足足科Phyllocladus和Prumnnopitys有亲缘关系。一个单独的原生cladoxylon francisiae标本可能代表了一个已灭绝的足足类。此外，还发现了两个与podocarpacae有亲缘关系的cf. Cupressinoxylon的分类单位。从营养和生殖大化石以及来自同一来源单元的花粉粒中，已经报道了与这些森林的亲缘关系一致的Podocarpaceae分类群的多样性。有些树林里有满是杂草的走廊。不同的生长环边界表明季节性，推断为季节性光的可用性。生长年轮的宽度表明木材来自成熟的树木，而一些年轮的宽度和类型表明温度和水分供应条件接近均匀。
Abstract During the early Eocene, Patagonia had highly diverse floras that are primarily known from compression and pollen fossils. Fossil wood studies from this epoch are scarce in the region and largely absent from the Laguna del Hunco flora, which has a highly diverse and excellently preserved compression assemblage. A collection of 26 conifer woods from the Laguna del Hunco fossil-lake beds (early Eocene, ca. 52 Ma) from central-western Patagonia was studied, of which 12 could be identified to genus. The dominant species is Phyllocladoxylon antarcticum, which has affinity with early-diverging Podocarpaceae such as Phyllocladus and Prumnnopitys. A single specimen of Protophyllocladoxylon francisiae probably represents an extinct group of Podocarpaceae. In addition, two taxonomic units of cf. Cupressinoxylon with putative affinity to Podocarpaceae were found. Diverse Podocarpaceae taxa consistent with the affinities of these woods were previously reported from vegetative and reproductive macrofossils as well as pollen grains from the same source unit. Some of the woods have galleries filled with frass. Distinct growth ring boundaries indicate seasonality, inferred to represent seasonal light availability. Growth ring widths suggest that the woods came from mature trees, whereas the widths and types of some rings denote near-uniform temperature and water availability conditions.