Tabulaconus Handfield: microstructure and its implication in the taxonomy of primitive corals
Tabulaconus Handfield: microstructure and its implication in the taxonomy of primitive corals
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DOI：
10.1017/s0022336000028122
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发表时间：
1987-01
影响因子：
1.4
通讯作者：
F. Debrenne;R. Gangloff;J. Lafuste
中科院分区：
文献类型：
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作者：
F. Debrenne;R. Gangloff;J. Lafuste
许多Tabulaconus Handfield， 1969年，在Adams泥质岩（早寒武纪，Tatonduk地区，阿拉斯加）的碳酸盐堆积中被收集。通过使用抛光超薄切片（2-3 μm厚）和扫描电子显微镜，研究了这种形式的壁结构，以及同时期的古藻类和藻类。微观结构比较的结果表明，尽管成岩作用发生了改变，但Tabulaconus的骨骼与目前已知的任何骨骼都不同，并且与相关的藻类或古藻类非常不同。它比在古珊瑚中发现的更精细，但还没有达到1976年在原始珊瑚Cothonion Jell和Jell中看到的复杂程度。一些细长单元的存在可能代表了向古生代珊瑚典型的纤维骨架迈出的第一步。本研究表明，成岩作用虽然改变了钙质骨架的原始微观结构，但所形成的结构和详细结构可以用于系统描述。Tabulaconus是由于存在初级隔和tabularium的结构而从gastroconides dae中移除的。许多被归为ba<s:1> atocyathus Vologdin属的物种，包括在古ocyatha中，似乎是Tabulaconus或非常接近的亲戚的例子。本文提出了一种订正的模式种——油螺科的描述。
Numerous specimens of Tabulaconus Handfield, 1969, have been collected in carbonate buildups within the Adams Argillite (Early Cambrian, Tatonduk area, Alaska). The wall structure of this form has been investigated, along with contemporaneous archaeocyaths and algae, through the use of polished ultra-thin sections (2–3 μm thick) and scanning electron microscopy. The results of this microstructural comparison indicate that despite diagenetic alteration Tabulaconus has a skeleton that is unlike any presently known and is quite distinct from associated algae or archaeocyaths. It is more elaborate than that found in the archaeocyaths but has not reached the stage of complexity seen in the primitive coral Cothonion Jell and Jell, 1976. The presence of some elongated units may represent an initial step towards the fibrous skeleton typical of Paleozoic corals. This study shows that even though diagenesis alters the original microstructure of calcareous skeletons, the resultant fabrics and detailed structures can be useful in systematic descriptions. Tabulaconus is removed from the Gastroconidae Kordae due to the presence of rudimentary septa and constitution of the tabularium. A number of species assigned to the genus Bačatocyathus Vologdin and included within the Archaeocyatha appear to be examples of Tabulaconus or very close relatives. An emended description of Tabulaconus kordae, the type species, is proposed.