Data from: Systematics of the ant genus Proceratium Roger (Hymenoptera, Formicidae, Proceratiinae) in China – with descriptions of three new species based on micro-CT enhanced next-generation-morphology

The genus Proceratium Roger, 1863 contains cryptic, subterranean ants that are seldom sampled and rare in natural history collections. Furthermore, most Proceratium specimens are extremely hairy and, due to their enlarged and curved gaster, often mounted suboptimally. As a consequence, the poorly observable physical characteristics of the material and its scarcity result in a rather challenging alpha taxonomy of this group. In this study, the taxonomy of the Chinese Proceratium fauna is reviewed and updated by combining examinations of traditional light microscopy with x-ray microtomography (micro-CT). Based on micro-CT scans of seven out of eight species, virtual 3D surface models were generated that permit in-depth comparative analyses of specimen morphology in order to overcome the difficulties to examine physical material of Proceratium. Eight Chinese species are recognized, of which three are newly described: Proceratium bruelheidei Staab, Xu & Hita Garcia, sp. n. and P. kepingmai sp. n. belong to the P. itoi clade and have been collected in the subtropical forests of southeast China, whereas P. shohei sp. n. belongs to the P. stictum clade and it is only known from a tropical forest of Yunnan Province. Proceratium nujiangense Xu, 2006 syn. n. is proposed as a junior synonym of P. zhaoi Xu, 2000. These taxonomic acts raise the number of known Chinese Proceratium species to eight. In order to integrate the new species into the existing taxonomic system and to facilitate identifications, an illustrated key to the worker caste of all Chinese species is provided, supplemented by species accounts with high-resolution montage images and still images of volume renderings of 3D models based on micro-CT. Moreover, cybertype datasets are provided for the new species, as well as digital datasets for the remaining species that include the raw micro-CT scan data, 3D surface models, 3D rotation videos, and all light photography and micro-CT still images. These datasets are available online (Dryad, Staab et al. 2018, http://dx.doi.org/10.5061/dryad.h6j0g4p).厚角猛蚁属（Proceratium Roger, 1863）包含一类隐蔽性地下蚂蚁，这类蚂蚁极难采集，且在自然历史馆藏中极为稀少。此外，绝大多数厚角猛蚁标本体表密被绒毛，加之其膨大且弯曲的后腹部，导致标本制作方式往往欠佳。正因如此，该类群标本的形态特征难以观测，加之标本稀缺，使得该类群的阿尔法分类学（alpha taxonomy）研究极具挑战性。本研究结合传统光学显微镜检查与X射线显微计算机断层扫描（micro-CT）技术，对中国厚角猛蚁属昆虫区系的分类学进行了修订与更新。基于8个物种中的7个物种的micro-CT扫描结果，我们生成了虚拟三维表面模型，可用于对标本形态开展深入的比较分析，从而克服了直接检视厚角猛蚁实物标本的困难。本研究共确认8个中国分布的厚角猛蚁物种，其中3个为新种：Proceratium bruelheidei Staab, Xu & Hita Garcia, sp. n.与P. kepingmai sp. n.隶属于P. itoi支系，采集自中国东南部的亚热带森林；而P. shohei sp. n.隶属于P. stictum支系，目前仅知其分布于云南省的一处热带森林中。本研究将Proceratium nujiangense Xu, 2006 syn. n.确立为P. zhaoi Xu, 2000的新异名。上述分类学修订使中国已知厚角猛蚁物种数量增至8个。为将新种纳入现有分类系统并便于物种鉴定，本文提供了所有中国分布物种工蚁品级的图解检索表，并辅以各物种的详细记述，包含高分辨率拼接图像以及基于micro-CT生成的三维模型体积渲染静态图像。此外，本研究还为3个新种提供了电子模式（cybertype）数据集，同时为其余物种提供了包含原始micro-CT扫描数据、三维表面模型、三维旋转视频以及所有光学摄影与micro-CT静态图像的数字数据集。这些数据集可在线获取（Dryad, Staab等，2018，http://dx.doi.org/10.5061/dryad.h6j0g4p）。