The arthropod class Diplopoda, the millipedes, ranks among the most diverse groups of terrestrial organisms, with over 12,000 species described. Although they play an important ecological role in most terrestrial ecosystems, little is known about the group's diversity, morphology, and phylogeny compared with other arthropod groups. We review diplopod natural history and discuss the historical and current literature pertaining to millipede morphology, ecology, chemical defenses, and the paleontological record of the group's ancient history. Diplopod systematics, past and present, are reviewed with a focus on taxonomy, collections, and biogeography. The phylogenetics of the class is reviewed, with particular attention on diplopod placement within the Myriapoda and emphasis on recent advances using molecular approaches to phylogenetic reconstruction. We present (a) the first combined morphological and molecular analysis of the millipede orders, and (b) a list of critically evaluated characteristics of nominal clades identifying putative apomorphies.

中文翻译：

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Myriapod类双足类（千足虫）的当前状态：分类学多样性和系统发育。

节肢动物类双足纲（千足动物）是陆地生物种类最多的种类之一，描述了超过12,000种。尽管它们在大多数陆地生态系统中起着重要的生态作用，但与其他节肢动物相比，它们的多样性，形态和系统发育知之甚少。我们回顾了双足类的自然历史，并讨论了与千足虫的形态，生态，化学防御以及该小组古代历史的古生物学记录有关的历史和当前文献。对Diplopod过去和现在的系统学进行了审查，重点是分类法，收藏和生物地理学。对该类的系统发育进行了回顾，特别要关注双足类动物在足纲内的放置，并强调使用分子方法进行系统发育重建的最新进展。我们提出（a）千足虫阶的首次组合形态学和分子分析，以及（b）鉴定出假定的无性型的名义进化枝的关键评价特征列表。