A cryptic species of the Tylonycteris pachypus complex (Chiroptera: Vespertilionidae) and its population genetic structure in southern China and nearby regions

The Effectiveness of Molecular, Karyotype and Morphological Methods in the Identification of Morphologically Conservative Sibling Species: An Integrative Taxonomic Case of the Crocidura attenuata Species Complex in Mainland China

The conservation of morphology has resulted in considerable issues in the taxonomy of small mammals, especially for the identification of sibling species. Moreover, it is often difficult to completely solve such taxonomic problems by relying only on a single research method. The genus Crocidura is one of the genera with a conservative morphology and high species diversity. Among them, Crocidura attenuata has been considered in the field as the most widely distributed and common species. In fact, it is a species complex containing multiple species, and the classification and distribution of this species is controversial. In this study, the species and distribution of the Crocidura attenuata species complex experienced an integrated revision using three different levels of research methods: molecular, karyotype and morphology. The results show that (1) the C. attenuata species complex contains four known species (C. attenuata, C. tanakae, C. anhuiensis and C. dongyangjiangensis) and a cryptic species distributed in Guangxi, which may be the same undescribed species as the "C. attenuata" distributed in Vietnam. (2) C. attenuata is only distributed around the Sichuan Basin, C. tanakae is the most widely distributed throughout Southern China, and C. anhuiensis and C. dongyangjiangensis are almost sympatric in Southeast China. Furthermore, (3) although the molecular method lacks a unified threshold for species classification, it can rapidly and effectively identify the species of the C. attenuata species complex. Although karyotype and morphology methods cannot completely solve the species classification issues in respect of the C. attenuata species complex, they can provide supplemental information for taxonomic purposes. Therefore, the integrated taxonomic method can present the advantages of different methodological levels, and will provide further evidence for the taxonomy of sibling species with a conservative morphology.

Karyotypic polymorphism of Crocidura tanakae (Eulipotyphla: Soricidae) and revision of the karyotype of C. attenuata in mainland China

Conventional karyotypes of Crocidura tanakae and C. attenuata collected from mainland China were examined by bone marrow and cell culture methods along with identification to species using molecular data. In contrast to C. tanakae from Taiwan, populations from mainland China were karyotypically polymorphic, varying in diploid number (2n) from 24 to 40 and fundamental number (FN) from 45 to 56. Autosomes are composed of 6–20 metacentric or submetacentric chromosomes, 0–8 subtelocentric chromosomes, and 0–24 telocentric chromosomes. These polymorphic karyotypes indicate the presence of two geographically separated races. The ancestral karyotype of C. tanakae potentially is the same as currently found on Taiwan: 2n = 40 and FN = 56. In contrast to C. tanakae, C. attenuata had a uniform karyotype (2n = 40, FN = 54) in mainland China, suggesting that previously reported karyotypic polymorphism in this species was an error due to the morphological crypsis between C. tanakae and C. attenuata in mainland China. The intricate karyotypic polymorphism of C. tanakae may be indicative of this species undergoing speciation.

Molecular phylogeographic analyses and species delimitations reveal that Leopoldamys edwardsi (Rodentia: Muridae) is a species complex

Leopoldamys edwardsi is a species with wide distribution ranges in southern China but is not discussed in studies on geographic variation and species differentiation. We used 2 mitochondrial (Cytb, CO1) and 3 nuclear (GHR, IRBP and RAG1) genes to clarify species phylogeography and geographical differentiation. Maximum likelihood (ML) and Bayesian phylogenetic inference (BI) trees consistently indicated that L. edwardsi is a species complex containing 3 main lineages with high Kimura-2-parameter (K2P) divergences (i.e. lineages L_N , L_S and L_HN ) found in the northern and southern China and Hainan Island, respectively. The 3 species delimitation methods, automated barcoding gap discovery, Bayesian poisson tree process analysis and Bayesian phylogenetics and phylogeography, consistently supported the existence of cryptic species. Divergence times among the main lineages were inferred to be during the Pleistocene, with L_HN /L_S split at 1.33 Ma and L_N /(L_HN +L_S ) at 2.61 Ma; the diversifications of L. edwardsi complex might be caused by the rapid uplifts of Tibetan Plateau, paleoclimate change and complex topography. The divergence between L_HN and L_S was probably related to the separation of Hainan Island from the mainland via the formation of the Qiongzhou Strait. Lineages L_N and (L_S +L_HN ) likely diverged due to the Wuyi-Nanling mountain range forming a dispersal barrier. Our results suggested that L. edwardsi complex contains at least 3 distinct species: L_HN represents L. hainanensis, endemic to Hainan Island and previously considered as a subspecies L. e. hainanensis; L_S represents a cryptic species distributed throughout the southern Chinese continent; and L_N represents the nominotypical species L. edwardsi.