College of Life Sciences, Sichuan Normal University, Chengdu, 610066, China.
Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China.
BMC Evol Biol. 2020 Feb 14;20(1):29. doi: 10.1186/s12862-020-1588-8.
Crocidura, the most speciose mammalian genus, occurs across much of Asia, Europe and Africa. The taxonomy of Chinese representatives has been studied primarily based on cursory morphological comparisons and their molecular phylogenetic analyses remain unexplored. In order to understand the phylogeny of this group in China, we estimated the first multilocus phylogeny and conducted species delimitation, including taxon sampling throughout their distribution range.
We obtained one mitochondrial gene (cytb) (~ 1, 134 bp) and three nuclear genes (ApoB, BRCA1, RAG1) (~ 2, 170 bp) for 132 samples from 57 localities. Molecular analyses identified at least 14 putative species that occur within two major well-supported groups in China. Polyphyletic C. wuchihensis appears to be composed of two putative species. Two subspecies, C. rapax rapax and C. rapax kurodai should be elevated to full species status. A phylogenetic tree based on mitochondrial gene from Asian Crocidura species showed that the C. rapax rapax is embedded within C. attenuata, making the latter a paraphyletic group. Three strongly supported undescribed species (C. sp.1, C. sp.2 and C. sp.3) are revealed from Zada County of Tibet (Western China), Hongjiang County of Hunan Province (Central China) and Dongyang County of Zhejiang Province (Eastern China), Motuo County of Tibet, respectively. The divergence time estimation suggested that China's Crocidura species began to diversify during the late Pliocene (3.66 Ma) and the Early Pleistocene (2.29 Ma), followed by a series of diversifications through the Pleistocene.
The cryptic diversity found in this study indicated that the number of species is strongly underestimated under the current taxonomy. We propose that the three undescribed species should be evaluated using extensive taxon sampling and comprehensive morphological and morphometric approaches. Climate change since the late Pliocene and the uplift of the Qinghai-Tibet Plateau may result in the diversification and speciation of China's Crocidura species. In short, the underestimated diversity underlines the need for a taxonomic revision of Chinese Crocidura species.
鼩形鼠是哺乳动物中物种最丰富的属，分布于亚洲、欧洲和非洲的大部分地区。中国代表种的分类学主要基于粗略的形态比较，而其分子系统发育分析仍未得到探索。为了了解该组在中国的系统发育，我们估计了第一个多基因系统发育，并进行了物种划定，包括在其分布范围内的分类群采样。
我们从 57 个地点的 132 个样本中获得了一个线粒体基因（细胞色素 b）（1,134 bp）和三个核基因（ApoB、BRCA1、RAG1）（2,170 bp）。分子分析鉴定出至少 14 种假定种存在于中国的两个主要支持的群中。多系的 C. wuchihensis 似乎由两种假定种组成。两个亚种，C. rapax rapax 和 C. rapax kurodai 应提升为全种地位。基于亚洲鼩形鼠物种的线粒体基因构建的系统发育树表明，C. rapax rapax 嵌入 C. attenuata 中，使后者成为一个并系群。从西藏扎达县（中国西部）、湖南洪江市（中国中部）和浙江东阳市（中国东部）、西藏墨脱县分别揭示了三个强烈支持的未描述种（C. sp.1、C. sp.2 和 C. sp.3）。分歧时间估计表明，中国的鼩形鼠物种在更新世晚期（3.66 Ma）和更新世早期（2.29 Ma）开始多样化，随后在更新世经历了一系列多样化。
本研究发现的隐存多样性表明，在当前分类学下，物种数量被严重低估。我们建议，应该使用广泛的分类群采样和全面的形态和形态测量方法来评估这三个未描述的种。更新世晚期以来的气候变化和青藏高原的隆起可能导致中国鼩形鼠物种的多样化和物种形成。总之，低估的多样性强调了对中国鼩形鼠物种进行分类修订的必要性。
