A new icriodontid conodont cluster with specific mesowear supports an alternative apparatus motion model for Icriodontidae

Increasing numbers of conodont discoveries with soft tissue preservation, natural assemblages and fused clusters of the hard tissue have strengthened the hypothesis regarding the function and mechanism of the conodont feeding apparatus. Exceptional fossil preservation serves as a solid basis for modern reconstructions of the conodont apparatus illustrating the complex interplay of the single apparatus elements. Reliable published models concern the ozarkodinid apparatus of Pennsylvanian and Early Triassic conodonts. Recognition of microwear and mammal-like occlusion, especially of platform elements belonging to individuals of the genus <i>Idiognathodus</i>, allows rotational closure to be interpreted as the crushing mechanism of ozarkodinid platform (P1) elements. Here we describe a new icriodontid conodont cluster of <i>Caudicriodus woschmidti</i> that consists of one pair of icriodontan (I) and 10 pairs of coniform (C1–5) elements, with I elements being preserved in interlocking position. The special kind of element arrangement within the fused cluster provides new insights into icriodontid apparatus reconstruction and notation of elements. However, orientation of coniform elements is limited to a certain degree by possible preservational bias. Four possible apparatus models are introduced and discussed. Recognition of specific wear on denticle tips of one of the icriodontan elements forms the basis for an alternative hypothesis of apparatus motion. Analysis of tip wear suggests a horizontal, slightly elliptical motion of opposed, antagonistically operating I elements. This is supported by similar tip wear from much better preserved, but isolated, elements of Middle Devonian icriodontids. More detailed interpretation of the masticatory movement will allow enhanced understanding of anatomical specifications, diet and palaeobiology of different euconodont groups.

越来越多带有软组织保存、自然共生体以及硬组织融合集群的牙形石（conodont）化石发现，强化了关于牙形石进食器官功能与运作机制的假说。
特异埋藏化石保存为现代牙形石器官重建提供了坚实基础，此类重建清晰展现了单个器官单元间的复杂相互作用。
已发表的可靠模型聚焦于宾夕法尼亚纪与早三叠世牙形石的奥扎克林德类（ozarkodinid）进食器官。
对微磨痕以及类哺乳动物咬合（尤其是Idiognathodus属个体的平台型单元）的识别，使得旋转闭合可被解读为奥扎克林德类平台（P1）单元的压碎机制。
本文记述了一个新的克里奥多类（icriodontid）牙形石融合集群——Caudicriodus woschmidti，该集群包含1对克里奥多型（I）单元与10对锥状（C1–5）单元，其中I单元以互锁位置保存。
该融合集群内特殊的单元排布方式，为克里奥多类器官重建与单元标注提供了全新视角。不过，锥状单元的取向在一定程度上受保存偏差的限制。
本文提出并讨论了四种可能的器官模型。对其中一个克里奥多型单元齿尖特定磨痕的识别，为器官运动的替代假说提供了依据。
对齿尖磨痕的分析表明，成对且拮抗运作的I单元存在水平、近似椭圆的运动模式。中泥盆世克里奥多类保存更佳但孤立的单元所呈现的类似齿尖磨痕，也佐证了这一结论。
对咀嚼运动的更详细解析，将有助于我们深入理解不同真牙形石类群的解剖学特征、食性与古生物学特性。