Biogeography and systematics of the eulipotyphlans (Genus Chimarrogale, Hylomys and Crocidura) from Peninsular Malaysia / Muhammad Farhan Abd Wahab

Muhammad Farhan, Abd Wahab (2022) Biogeography and systematics of the eulipotyphlans (Genus Chimarrogale, Hylomys and Crocidura) from Peninsular Malaysia / Muhammad Farhan Abd Wahab. PhD thesis, Universiti Malaya.

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Abstract

Inspired by the myriad of questions regarding the taxonomic status and genetic relationships of fauna from Peninsular Malaysia, research on the three selected Eulipotyphlan (Chimarrogale hantu, Hylomys suillus and Crocidura monticola) were conducted. The first objective is to elucidate the taxonomic status of Chimarrogale hantu from Peninsular Malaysia and its genus among Asiatic water shrews through genetic and morphological analyses. Chimarrogale hantu formed a distinct clade that diverged from other Chimarrogale species (with morphological variation exist and distinct haplotypes) and other genera in the tribe Nectogalini. The C. hantu clade is closely related to the Crossogale phaeura and high genetic divergence were also observed when compared to other species. Chimarrogale hantu was proved genetically and morphologically merit species rank and reclassifying it in the genus Crossogale along with Cr. phaeura. For a better understanding of the relationships among water shrews, future comprehensive reviews of the Sundaic water shrews’ group should include Chimarrogale sumatrana from Sumatra, Indonesia. The second objective is to reassess the taxonomic status of the Hylomys species/subspecies from Peninsular Malaysia and the Sunda Islands. The external morphology and the skull measurements of the studied taxa is within the range of H. s. maxi from Peninsular Malaysia and Sumatra. Hylomys samples from Genting Highlands formed a clade with H. s. maxi from Cameron Highlands and Fraser’s Hill as well as Sumatra. However, they were separated from Sumatran species, H. parvus and H. s. suillus from Java. Low genetic distances were detected among the studied taxa with H. s. maxi and high genetic distances were observed when compared to other Hylomys taxa. Based on these facts, species-level taxonomic status was proposed within the currently recognized Hylomys suillus subspecies lineage from Peninsular Malaysia and the Sunda Islands. Thirdly, the genetic relationships of available Crocidura samples from Peninsular Malaysia and Kalimantan were re-evaluated based on cytochrome b gene sequences to confirm the taxonomic status. The analysis led to the discovery of inter-island species, Crocidura neglecta (samples from Bukit Rengit and Ulu Gombak) and two other Crocidura species, Crocidura cf. monticola 1 from Peninsular Malaysia and Crocidura cf. monticola 2 from Kalimantan. A monophyletic clade of C. cf. monticola 1 was formed from Wang Kelian, Maxwell Hill, Cameron Highlands and Fraser’s Hill which consist of low genetic distance among samples. Other Crocidura samples from Bukit Rengit and Ulu Gombak formed a clade with C. neglecta from Sumatra and Kalimantan and separated with C. cf. monticola 1 with high genetic distance, indicating both as valid species. Meanwhile, the Crocidura sample from Kalimantan formed a clade with the sample from Borneo, C. cf. monticola 3. Interestingly, high genetic distance was evident between these two samples, considering the former as a distinct species, C. cf. monticola 2. All these Crocidura samples (previously known as Crocidura monticola) also form a separated clade with terra typica, C. monticola from Java supported with high genetic distance suggesting that they are specifically distinct on the species level. To conclude, the diversification of three Eulipotyphlan species in Peninsular Malaysia influenced by Pleistocene events and their taxonomic status has been clarified in this study.

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