Kinorhynch segmentation differs from the patterns found in Chordata, Arthropoda and Annelida which have coeloms and circulatory systems. Due to these differences and their obsolete status as ‘Aschelminthes’, the microscopic kinorhynchs are often not acknowledged as segmented bilaterians. Yet, morphological studies have shown a conserved segmental arrangement of ectodermal and mesodermal organ systems with spatial correspondence along the anterior-posterior axis. However, a few aberrant kinorhynch lineages present a worm-like body plan with thin cuticle and less distinct segmentation, and thus their study may aid to shed new light on the evolution of segmental patterns within Kinorhyncha. Here we found the nervous system in the aberrant Cateria styx and Franciscideres kalenesos to be clearly segmental, and similar to those of non-aberrant kinorhynchs; hereby not mirroring their otherwise aberrant and posteriorly shifted myoanatomy. In Zelinkaderes yong, however, the segmental arrangement of the nervous system is also shifted posteriorly and misaligned with respect to the cuticular segmentation. The morphological disparity together with the distant phylogenetic positions of F. kalenesos, C. styx and Z. yong support a convergent origin of aberrant appearances and segmental mismatches within Kinorhyncha.

中文翻译：

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重新审视kinorhynch分割：三种异常物种神经系统中节段模式的变化

Kinorhynch 分割不同于在具有体腔和循环系统的脊索动物、节肢动物和环节动物中发现的模式。由于这些差异及其作为“Aschelminthes”的过时状态，微观kinorhynchs 通常不被认为是分段的双边动物。然而，形态学研究表明外胚层和中胚层器官系统的保守节段排列，沿前后轴具有空间对应关系。然而，一些异常的kinorhynch谱系呈现出一种蠕虫状的身体结构，具有薄的角质层和不太明显的分割，因此他们的研究可能有助于揭示Kinorhyncha内节段模式的演变。在这里，我们发现异常的 Cateria styx 和 Franciscideres kalenesos 的神经系统明显是分段的，和那些非异常的kinorhynchs相似；特此不反映他们否则异常和向后移动的肌肉解剖结构。然而，在 Zelinkaderes yong 中，神经系统的节段排列也向后移动并且相对于表皮节段错位。形态差异以及 F. kalenesos、C. styx 和 Z. yong 的远距离系统发育位置支持 Kinorhyncha 内异常外观和节段不匹配的收敛起源。