Pseudechiniscus is the second most species-rich genus in Heterotardigrada and in the family Echiniscidae. However, previous studies have pointed out polyphyly and heterogeneity in this taxon. The recent erection of the genus Acanthechiniscus was another step in making Pseudechiniscus monophyletic, but species identification is still problematic. The present investigation aims at clarifying biodiversity and taxonomy of Pseudechiniscus taxa, with a special focus on species pertaining to the so-called ‘suillus–facettalis group’, by using an integrated approach of morphological and molecular investigations. The analysis of sequences from specimens sampled in Europe and Asia confirms the monophyly of the genus Pseudechiniscus. Inside the genus, two main evolutionary lineages are recognizable: the P. novaezeelandiae lineage and the P. suillus–facettalis group lineage. Inside the P. suillus– facettalis group, COI molecular data points out a very high variability between sampled localities, but in some cases also among specimens sampled in the same locality (up to 33.3% p-distance). The integrated approach to the study of Pseudechiniscus allows confirmation of its monophyly and highlights the relationships in the taxon, pointing to its global distribution.

中文翻译：

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对 Pseudechiniscus suillus-facettalis 群内生物多样性的综合研究（Heterotardigrada：Echiniscidae）

Pseudechiniscus 是 Heterotardigrada 和 Echiniscidae 中物种丰富度第二高的属。然而，先前的研究已经指出了该分类群的多系性和异质性。最近 Acanthechiniscus 属的建立是使 Pseudechiniscus 单系化的又一步，但物种鉴定仍然存在问题。本调查旨在通过使用形态学和分子调查的综合方法，阐明 Pseudechiniscus 类群的生物多样性和分类学，特别关注与所谓的“猪-切面群”有关的物种。对在欧洲和亚洲取样的标本的序列分析证实了 Pseudechiniscus 属的单一性。在该属内，可以识别两个主要的进化谱系：P. novaezeelandiae 谱系和 P. novaezeelandiae 谱系。suillus-facettalis 组谱系。在 P. suillus-facettalis 组内，COI 分子数据指出采样位置之间存在非常高的变异性，但在某些情况下，同一位置采样的样本之间也存在非常高的变异性（高达 33.3% 的 p 距离）。对 Pseudechiniscus 研究的综合方法可以确认其单一性并突出分类群中的关系，指出其全球分布。