**Acknowledgements**

The author is indebted to Maharadatun Kamsi, the curator of vertebrate collection of the Museum Zoologicum Bogoriense, Indonesian Academy of Sciences (LIPI), as well as Kelvin Lim, the collection manager of Lee Kong Chian of Natural History Museum, National University of Singapore. I also wish to thank Dr. Tsuyoshi Ito for helpful suggestion in biostatistics work and data analysis and Thomas Priyo Ertanto, who drew the map in this publication. This research was financially supported by The Asahi Glass Foundation to HI (ID: 2017-F-06). We further thank Mao Asami, Indra Sutisna, Akhmad Herdiyanto, Nanang Supriatna, and Kurnianingsih for support during sample collection and laboratory work.
