Traditionally, biostratigraphy of the terminal Famennian (Upper Devonian) and lower part of the Tournaisian (Mississippian) is based on phylogeny of the conodont genus Siphonodella Branson and Mehl. This study is focused on a Siphonodella species with a long taxonomical history. For the last three decades it was known as S. hassi Ji, 1985 and was used as a zonal index for the eponymic hassi Zone, used worldwide. However, this species faces several taxonomical problems. The main issue is the homonymy of S. hassi and S. cooperi hassi Thompson and Fellows, 1970. However, S. cooperi hassi is a subjective junior synonym of S. obsoleta Hass, 1959. The oldest junior synonym of S. hassi is S. wilberti Bardasheva, Bardashev, Weddige and Ziegler, 2004, and, according to a statement by the International Commission on Zoological Nomenclature, the latter represents the only available name for this species. An additional problem is the similar morphology of early ontogenetic stages of S. wilberti and S. quadruplicata Branson and Mehl, 1944, the youngest stratigraphically important siphonodellid species. In advanced ontogenetic stages, P₁ elements that possess two rostral ridges belong to S. wilberti only. The smaller P₁ elements having two or less rostral ridges comprise the S. wilberti- S. quadruplicata plexus. Maintenance of the wilberti Zone in the Tournaisian global zonation is suggested.

传统上，末端法门尼阶（上泥盆纪）和图尔奈阶（密西西比河）下部的生物地层学是基于牙形石属Siphonodella Branson和Mehl的系统发育的。这项研究的重点是具有悠久分类学历史的虹吸虫物种。在过去的三十年中，它被称为S. hassi Ji（1985年），并被用作世界各地使用的同名hassi地带的区域索引。但是，该物种面临一些分类学问题。主要问题是S. hassi和S. cooperi hassi Thompson and Fellows，1970年的同名词。但是，S。cooperi hassi是S. obsoleta的主观初级同义词。Hass，1959年。S. hassi的最早的下级同义词是S. wilberti Bardasheva，Bardashev，Weddige和Ziegler，2004年，根据国际动物学命名委员会的声明，后者代表该物种的唯一可用名称。 。另外的问题是早期个体发育阶段的相似形态学S. wilberti和S. quadruplicata布兰森和Mehl的，1944年，最年轻的地层重要siphonodellid物种。在晚期成因阶段，拥有两个延髓脊的P ₁元素仅属于S. wilberti。具有两个或更少的峰形脊的较小的P ₁元素包括S. wilberti - S. quadruplicata plexus。建议对图尔奈地区的全球分区中的wilberti区进行维护。