Conodont P₁ elements of ‘Siphonodella’ are the most important guide fossils for the Tournaisian and topmost Famennian. Hypotheses on the origin and evolution of the elictognathid (‘Siphonodella’) clade are based exclusively on the morphology of one pair of elements in the 15 element apparatus, because of difficulties with its reconstruction. An unusually rich sample taken from the Kowala Quarry in the Holy Cross Mountains, dominated by the core elictognathid species ‘S.’ cooperi, enables corroboration of the interpretation by Sandberg et al. (1978) and falsification of some more recent hypotheses. The elements P₁ and P₂ of ‘S.’ cooperi show a relatively narrow population variability and do not change morphologically in the course of their ontogeny. In contrast, elements S and M profoundly transformed their pattern of denticulation and general shape during growth. Juveniles are relatively underived and rather easily homologized with elements of other polygnathid apparatuses, but adults are of bizarre morphology unlike any other conodonts. Such a pattern of ontogenetic transformation makes it likely that small P₂ elements of relatively generalized morphology and mature Dinodus-type S elements associated with P₁ elements of ‘S.’ praesulcata in a Kowala sample taken from the topmost Famennian nodular limestone bed, belong together to the same apparatus. No Devonian conodont apparatus is known that could be compared with the highly derived ‘Siphonodella’ as its possible ancestor. Apparently, the elictognathid lineage immigrated to the Rheic Ocean realm from an unknown source near the end of the Devonian.

中文翻译：

---

早石炭世尖颌牙形齿象'Siphonodella'的口腔器官组成

' Siphonodella '的牙形石P ₁元素是图尔奈阶和法门阶最重要的向导化石。由于难以重建，关于 elictognathid (' Siphonodella ') 进化枝的起源和进化的假设完全基于 15 元素装置中一对元素的形态。取自圣十字山脉的科瓦拉采石场的异常丰富的样本，主要是核心 elictognathid 物种“ S”。cooperi，能够证实 Sandberg等人的解释。(1978) 和一些最近的假设的证伪。元素P ₁和P ₂的'小号“。cooperi显示出相对狭窄的种群变异性，并且在其个体发育过程中不会发生形态变化。相比之下，元素 S 和 M 在生长过程中深刻地改变了它们的齿状结构和一般形状。幼鱼相对不衍生，很容易与其他多颌类动物的元素同源，但成鱼的形态与任何其他牙形石都不一样。这种个体遗传转化模式使得具有相对广义形态的小P ₂元素和成熟的恐龙型S 元素与' S '的P ₁元素相关联。普拉苏卡塔在取自法门阶最顶部球状石灰岩床的科瓦拉样本中，它们属于同一仪器。没有已知的泥盆纪牙形石器可以与高度派生的“ Siphonodella ”作为其可能的祖先进行比较。显然，长颌动物系在泥盆纪末期从一个未知来源迁移到了莱茵洋领域。