First South American Record of Winteroxylon , Eocene of Laguna del Hunco (Chubut, Patagonia, Argentina): New Link to Australasia and Malesia
First South American Record of Winteroxylon , Eocene of Laguna del Hunco (Chubut, Patagonia, Argentina): New Link to Australasia and Malesia
复制标题
第一个南美冬木记录，Laguna del Hunco 始新世（阿根廷巴塔哥尼亚丘布特）：与澳大利亚和马来西亚的新联系
DOI：
10.1086/712427
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发表时间：
2021
影响因子：
2.3
通讯作者：
Gandolfo, María A.
中科院分区：
文献类型：
--
作者：
Brea, Mariana;Iglesias, Ari;Wilf, Peter;Moya, Eliana;Gandolfo, María A.
研究前提：冬青科( Winteraceae)是南半球广泛分布的热带乔木和灌木。今天，在澳大利亚东部、新西兰、马来西亚、大洋洲、马达加斯加和新热带地区发现了这种科，分布在热带到温带的干燥到潮湿的气候地区。南半球与冬青科有关的木材化石记录仅限于南极半岛的晚白垩世。在这里，我们提供了一个保存完好的树干次生木质部的详细解剖描述从早期始新世拉古纳德尔亨科遗址，惠特雷拉组，巴塔哥尼亚(楚布特省，阿根廷)，这是参考一新种温特沃伦(哥特沃德)Poole和Francis。方法 该木材被保存为硅质过矿化；它是用标准的岩石学技术切片，并在光学和扫描电子显微镜下观察。 保存在化石中的冬青科植物的诊断解剖学特征包括：缺乏生长轮，缺乏维管，横截面为矩形且具圆形边缘凹坑的管胞，弥散的轴向薄壁组织，射线显示两个不同的大小范围(单列双列或多列，3-15个细胞宽)，存在含有硬化巢的异质细胞射线，细胞内容物暗，以及油细胞。这一新化石物种与Zygogyums.l中现存的属最相似。产于澳大拉西亚和马来热带雨林的分支；其解剖结构与现存的布比亚属非常相似。新的巴塔哥尼亚冬青科化石木材的特征是射线中存在硬化巢和油细胞，这与以前描述的冬季木本植物的不同。结论： 在保留了显著特征的基础上，我们建立了冬季木本植物。11月这一新化石是南美洲冬青科第一个可靠的大型化石记录，支持了该科在大陆的丰富孢粉记录，也是Zygogyums.l的最古老记录。在温暖的早新生代期间，南美洲和澳大拉西亚之间通过南极洲建立了漫长的生物地理联系。
Premise of research. Winteraceae, a family within the Canellales, is composed of tropical trees and shrubs broadly distributed in the Southern Hemisphere. The family is found today in eastern Australia, New Zealand, Malesia, Oceania, Madagascar, and the Neotropics across a range of dry to wet tropical to temperate climate regions. The fossil record of woods related to the Winteraceae in the Southern Hemisphere is limited to the Late Cretaceous of the Antarctic Peninsula. Here, we present a detailed anatomical description of the secondary xylem of a well-preserved trunk from the early Eocene Laguna del Hunco site, Huitrera Formation, Patagonia (Chubut Province, Argentina), that is referable to a new species of the genusWinteroxylon(Gottwald) Poole and Francis.Methodology. The wood is preserved as a siliceous permineralization; it was sectioned using standard petrographic techniques and observed under both light and scanning electron microscopy. The anatomy was compared with that of extant and fossil species of Winteraceae.Pivotal results. The diagnostic anatomical features of Winteraceae preserved in the fossil include an absence of growth rings, a lack of vessels, tracheids that are rectangular in cross section with circular bordered pits, diffuse axial parenchyma, rays showing two distinct size ranges (uniseriate-biseriate or multiseriate, 3–15 cells wide), and the presence of heterocellular rays containing sclerotic nests, cells with dark contents, and oil cells. The new fossil species most resembles extant genera within theZygogynums.l. clade from Australasian and Malesian rain forests; its anatomy is very similar to that of the extant genusBubbia. The new Patagonian Winteraceae fossil wood is characterized by the presence of sclerotic nests and oil cells in the rays, which differ from those of previously described species ofWinteroxylon.Conclusions. On the basis of the distinctive characters preserved, we erectWinteroxylon oleiferumsp. nov. The new fossil is the first reliable macrofossil record of Winteraceae from South America, supporting the abundant palynological record of the family from the continent, and it is the oldest record of theZygogynums.l. clade, adding to the long list of southern biogeographic connections between South America and Australasia via Antarctica during the warm early Cenozoic.