The little-known western Eurasian taxa of the Phaedusinae (land snail family Clausiliidae) are Tertiary relicts, which are widely separated geographically from the rest of the subfamily occurring in eastern Eurasia. In order to elucidate the phylogenetic relationships of this group, we carried out molecular analyses with 11 of the 16 genera using nuclear gene sequences. Our results revealed that within the subfamily, Nothoserrulina and Pamphylica, together with Caspiophaedusa, Dobatia, Pravispira, and Serrulina, belong to a clade that is sister to that of all east Eurasian Phaedusinae except Synprosphyma. In contrast, Graecophaedusa, Laeviphaedusa, Pontophaedusella, and Serrulinella, together with Pontophaedusa, belong to paraphyletic lineages diverging between the branching point of these clades and that of the most basal Synprosphyma lineage. Laeviphaedusa and Pontophaedusella represent the earliest western Eurasian lineages, estimated to date back to the Eocene–Oligocene boundary. Comparison of our phylogeny to morphological traits of the genera identified clade-specific character states of the shells and the reproductive organs. Based on fossil records and on palaeogeographical and palaeofloristic data, we also propose a model for the geographical origin and radiation of this subfamily in Eurasia.

中文翻译：

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欧亚大陆西部的斐杜丝亚科（腹足纲：茎节纲：Clausiliidae）的系统发育和多样性


鲜为人知的欧亚西部类群 Phaedusinae（陆地蜗牛科 Clausiliidae）是第三纪遗迹，在地理上与欧亚大陆东部的其他亚科相距甚远。为了阐明该类群的系统发育关系，我们利用核基因序列对 16 个属中的 11 个进行了分子分析。我们的结果显示，在该亚科中，Nothoserrulina 和 Pamphylica 以及 Caspiophaedusa、Dobatia、Pravispira 和 Serrulina 属于一个进化枝，与除 Synprosphyma 之外的所有东欧亚 Phaedusinae 的进化枝属于姊妹进化枝。相比之下，Graecophaedusa、Laeviphaedusa、Pontophaedusella 和 Serrulinella 以及 Pontophaedusa 属于并系谱系，在这些进化枝的分支点和最基础的 Synprosphyma 谱系的分支点之间出现分歧。 Laeviphaedusa 和 Pontophaedusella 代表了欧亚大陆西部最早的谱系，估计可以追溯到始新世-渐新世边界。将我们的系统发育与属的形态特征进行比较，确定了壳和生殖器官的进化枝特异性特征状态。根据化石记录以及古地理和古植物学数据，我们还提出了该亚科在欧亚大陆的地理起源和辐射的模型。