The apparatus composition and architecture of Erismodus quadridactylus and the implications for element homology in prioniodinin conodonts
The apparatus composition and architecture of Erismodus quadridactylus and the implications for element homology in prioniodinin conodonts
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DOI：
10.1002/spp2.1257
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发表时间：
2019-05
影响因子：
2.3
通讯作者：
R. Dhanda;D. Murdock;J. Repetski;P. Donoghue;M. P. Smith
中科院分区：
文献类型：
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作者：
R. Dhanda;D. Murdock;J. Repetski;P. Donoghue;M. P. Smith
对碘朊牙形刺的器械组成和结构了解甚少，这主要是因为化石记录中很少有碘朊牙形刺类群具有铰接式口腔喂养器械（自然组合），但也由于其组成元素的高度可变的分层形态使得器械重建存在问题。本文描述了一种来自美国北达科他州（晚奥陶世）Sandbian的prooniodinus quadridactylus （Stauffer）。该组合表明，Erismodus的仪器结构与晚古生代prioniodinins，即Kladognathus Rexroad和Hibbardella Bassler相似，但也与ozarkodinin的仪器相似。此外，有证据表明，就其推断的P元素的位置而言，E. quadridactylus与balognathid结构具有拓扑相似性。这里提出的仪器组成和结构表明，至少就M-S阵列而言，“ozarkodinin - type”bauplan可能在龋类中更广泛地具有代表性。该组合表明，传统上被认为属于S数组的元素形态型是M元素，而其他传统上被解释为P元素的元素形态型则存在于S数组中。这些观察结果被用来作为基础，提炼元素同源性的概念之间的磷碘牙形刺和他们的近亲。
The apparatus composition and architecture of prioniodinin conodonts is poorly understood, largely because few prioniodinin taxa are represented by articulated oral feeding apparatuses (natural assemblages) in the fossil record, but also due to the highly variable gradational morphology of their constituent elements that makes apparatus reconstruction problematic. We describe here a natural assemblage of Erismodus quadridactylus (Stauffer), a prioniodinin, from the Sandbian (Late Ordovician) of North Dakota, USA. The assemblage demonstrates that the apparatus architecture of Erismodus is similar to those of late Palaeozoic prioniodinins namely, Kladognathus Rexroad and Hibbardella Bassler, but also has similarities with ozarkodinin apparatuses. In addition, there is evidence to suggest that E. quadridactylus shares topological similarities to balognathid architecture, with respect to the position of its inferred P elements. The apparatus composition and architecture presented here indicate that, at least with respect to the M–S array, an ‘ozarkodinin‐type’ bauplan is probably more widely representative across prioniodontids. The assemblage demonstrates that element morphotypes traditionally considered to lie within the S array are M elements, whereas others traditionally interpreted as P elements are found in the S array. These observations are used as a basis for refining concepts of element homology among prioniodinin conodonts and their closest relatives.