PARARAUCARIA DELFUEYOI SP NOV FROM THE LATE JURASSIC CANADON CALCAREO FORMATION, CHUBUT, ARGENTINA: INSIGHTS INTO THE EVOLUTION OF THE CHEIROLEPIDIACEAE
PARARAUCARIA DELFUEYOI SP NOV FROM THE LATE JURASSIC CANADON CALCAREO FORMATION, CHUBUT, ARGENTINA: INSIGHTS INTO THE EVOLUTION OF THE CHEIROLEPIDIACEAE
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DOI：
10.1086/668612
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发表时间：
2013-03-01
影响因子：
2.3
通讯作者：
Stockey, Ruth A.
中科院分区：
文献类型：
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作者：
Escapa, Ignacio H.;Cuneo, Nestor R.;Stockey, Ruth A.
在阿根廷巴塔哥尼亚丘布特省晚侏罗世Canadon Calcareo组的埃斯坦西亚Vilan地区发现了16个圆柱形针叶树球果，提供了解剖学上保存完好的标本，允许描述第二种Pararaucaria（Cheirolepidiaceae）。新种Pararaucaria delfueyoi与模式种Pararaucaria patagonica的一般特征相似，但具有特定的特征诊断组合，包括球果大小，种子数量，组织学特征和种子大小。标本是圆柱形的，具有狭窄的轴，承担螺旋排列的苞片/鳞片复合体。苞片和鳞片在90度时从轴上分叉，几乎立即彼此分离。胚珠鳞片向球果边缘延伸，然后拱起，将两个倒置的无翅种子包裹在一个组织袋中。虽然标本被磨损，以至于胚珠鳞片的远端区域没有被保存下来，但这种形态学和组织学特征的结合允许将P. delfueyoi确定为Cheirolepidiaceae。该锥与一种未描述的南洋杉属物种共同出现，扩展了该组合的地理和地层范围，该组合以前仅在巴塔哥尼亚的圣克鲁斯省的中侏罗世发现。这扩展了知识的解剖变异之间的种子球花，提高了我们的理解针叶树种子球花结构的同源关系。
The discovery of 16 cylindrical conifer seed cones at the Estancia Vilan locality in the Late Jurassic Canadon Calcareo Formation of Chubut Province, Patagonia, Argentina, provides anatomically preserved specimens, allowing for the description of a second species of Pararaucaria (Cheirolepidiaceae). The new species, Pararaucaria delfueyoi, is similar in general features to the type species, Pararaucaria patagonica, but has a specifically diagnostic combination of characters that include cone size, seed number, features of histology, and seed size. Specimens are cylindrical with a narrow axis that bears helically arranged bract/scale complexes. The bract and scale diverge from the axis at 90 and separate from each other almost immediately. The ovuliferous scale extends toward the margin of the cone and then arches over to enclose two inverted nonwinged seeds within a pocket of tissue. Although the specimens are abraded such that the distal regions of the ovuliferous scales are not preserved, this combination of morphological and histological characters allows for the assignment of P. delfueyoi to the Cheirolepidiaceae with confidence. The co-occurrence of this cone with an undescribed species of Araucaria extends the geographic and stratigraphic ranges of this association, which previously has been known only from the Middle Jurassic of Santa Cruz Province of Patagonia. This extends the knowledge of anatomical variation among seed cones of Cheirolepidiaceae and improves our understanding of homology relationships for conifer seed cone structures.