Early Eocene Spore and Pollen Assemblages from the Laguna del Hunco Fossil Lake Beds, Patagonia, Argentina
Early Eocene Spore and Pollen Assemblages from the Laguna del Hunco Fossil Lake Beds, Patagonia, Argentina
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DOI：
10.1086/708386
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发表时间：
2020-07-01
影响因子：
2.3
通讯作者：
Wilf, Peter
中科院分区：
文献类型：
--
作者：
Barreda, Viviana D.;del Carmen Zamaloa, Maria;Wilf, Peter
研究的优先权。始新世早期的拉古纳德尔洪科（LH）化石遗址位于阿根廷丘布特省西北部，是世界上保存最完好、种类最多的古植物群之一。古植物区系包括蕨类植物、裸子植物和开花植物。尽管对它的大型化石记录的了解迅速增长，但对该遗址的孢粉学内容知之甚少。在这里，我们提出了第一个分散的孢子花粉组合从LH恢复。方法论从Tufolitas de LH（Huitrera组）的7个地层水平采集了孢粉学样品，其中6个产生了孢粉形。我们确定了化石形态型的植物亲缘关系，并提供了一些分类群的系统描述。此外，我们建立LH和其他巴塔哥尼亚始新世的地方之间的相似性，我们比较了LH的孢粉学和以前的大花记录。初步结果。我们确定了56种孢子和花粉和28个植物科，其中8个（桫椤科，Schizaeaceae，水龙骨科，菊科，金粟兰科，Nothofagaceae，Rubiaceae和榆科）是可靠的首次报道。在其他始新世巴塔哥尼亚孢粉植物群中，LH组合类似于Pampa de Jones/Nahuel Huapi Este和Conflulae。结论. LH孢子花粉组合通过纳入新的分类群（例如，菊科，有一个形态型，代表了巴塔哥尼亚最古老的记录。新的数据也加强了之前从宏化石中报道的植物家族的存在，例如胡桃科，其花粉粒与Engelhardia-Alfaro类群和壳斗科（Castaneoideae）的花粉粒相似，补充了叶和生殖结构的宏化石记录。
Premise of research. The early Eocene Laguna del Hunco (LH) fossil site, northwestern Chubut Province, Argentina, holds one of the best-preserved and most diverse paleofloras worldwide. The paleoflora comprises ferns, gymnosperms, and flowering plants. Despite the rapidly growing knowledge of its macrofossil record, little is known about the site's palynological content. Herein, we present the first dispersed spore-pollen assemblages recovered from LH. Methodology. Palynological samples were collected from seven stratigraphic levels of the Tufolitas de LH (Huitrera Formation), of which six yielded palynomorphs. We determine the botanical affinities of fossil morphotypes and provide systematic descriptions of some taxa. In addition, we establish similarities between LH and other Patagonian Eocene localities, and we compare palynological and prior megafloral records from LH. Pivotal results. We identify 56 spore and pollen species and 28 plant families, of which eight (Cyatheaceae, Schizaeaceae, Polypodiaceae, Asteraceae, Chloranthaceae, Nothofagaceae, Rubiaceae, and Ulmaceae) are reliably reported from the site for the first time. Among other Eocene Patagonian palynofloras, the LH assemblage is similar to Pampa de Jones/Nahuel Huapi Este and Confluencia. Conclusions. The LH spore-pollen assemblages augment the plant fossil record for this significant Eocene locality by incorporating new taxa (e.g., Asteraceae, with one morphotype that represents the oldest record of the family in Patagonia). The new data also reinforce the presence of plant families previously reported from macrofossils, such as Juglandaceae, with pollen grains similar to those of theEngelhardia-Alfaroagroup, and Fagaceae (Castaneoideae), complementing the macrofossil record of leaves and reproductive structures.