East London Museum, 319 Oxford Street, East London, 5201, South Africa; Rhodes University, PO Box 94, Grahamstown, South Africa.
Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK; Royal Belgian Institute of Natural Sciences, Vautierstraat 29, B-1000 Brussels, Belgium.
Mol Phylogenet Evol. 2019 Feb;131:193-210. doi: 10.1016/j.ympev.2018.09.018. Epub 2018 Sep 29.
The genus Chondrocyclus Ancey, 1898 contains the majority of southern African members of the Cyclophoridae, a large family of operculate land snails. We present the first molecular phylogeny of the genus based on two mitochondrial genes (16S and CO1) and complement this with an appraisal of morphological characters relating to the shell and soft parts. Worn shells on which some descriptions and records of different species were based appear to be indistinguishable morphologically, creating taxonomic confusion. We show that Chondrocyclus s.l. underwent two major radiations, one Afromontane and the other largely coastal. Accordingly, we recommend a revision recognising two genera. Chondrocyclus s.s. contains four monophyletic lineages, each characterized by a combination of morphological features. The Afromontane group is shown to be a species complex; relationships within this complex could not be resolved due to insufficient DNA sequence data. The molecular data confirms the monophyly of seven currently recognised species and provides evidence for at least twelve undescribed species; the morphological data are broadly consistent with this finding. The morphological data suggest that the two species from countries to the north of South Africa should be removed from the genus, and that Chondrocyclus sensu lato is endemic to South Africa. The historical biogeography of this group of microhabitat specialists with poor dispersal abilities contributes an additional, phylogenetically independent taxon to our understanding of the processes generating biodiversity in southern Africa, a natural laboratory for palaeobiogeography. All taxa are narrow-range endemics, underlining the importance of conserving South Africa's threatened forest habitats.
软骨环属（Chondrocyclus Ancey, 1898）包含了旋螺科（Cyclophoridae）中大多数的南部非洲成员，这是一个大型的有盖陆生蜗牛科。我们基于两个线粒体基因（16S 和 CO1）首次提出了该属的分子系统发育，并结合对壳和软体部分相关形态特征的评估来补充这一研究。由于磨损的贝壳在不同物种的描述和记录中被使用，而且这些贝壳在形态上似乎无法区分，从而导致了分类上的混淆。我们表明，软骨环属（Chondrocyclus s.l.）经历了两次主要的辐射，一次是在 Afromontane，另一次主要是在沿海地区。因此，我们建议进行一次修订，承认两个属。软骨环属（Chondrocyclus s.s.）包含四个单系谱系，每个谱系都有形态特征的组合来加以区分。Afromontane 组被证明是一个物种复合体；由于 DNA 序列数据不足，无法解决该复合体内部的关系。分子数据证实了目前公认的七个物种的单系性，并提供了至少十二个未被描述的物种的证据；形态数据与这一发现基本一致。形态数据表明，来自南非北部国家的两个物种应从该属中移除，并且 Chondrocyclus s.l. 是南非特有的。作为具有不良扩散能力的小生境专家，该组的历史生物地理学为我们了解南部非洲生物多样性形成过程提供了一个额外的、与系统发育无关的分类单元，南部非洲是古生物学的天然实验室。所有的分类单元都是狭窄范围的特有种，这突显了保护南非受威胁森林栖息地的重要性。
