Acknowledgements
We gratefully acknowledge an AcRF Tier 1 grant from the Singapore Ministry of Education (National University of Singapore (NUS) Grant No. R-154-000-A32-114). KWJC was supported by the NUS President’s Graduate Fellowship and CLW was supported by funding from the Faculty of Science, NUS. We thank the Economic Planning Unit in the Prime Minister’s Department of Malaysia (UPE 40/200/19/3440) and the Sabah Biodiversity Council, Yayasan Sabah, Danum Valley Conservation Management Committee and SEARPP (JKM/MBS.1000-2/2JLD.3(9)) for granting us permission to conduct field surveys. We acknowledge Kelvin Lim Kok Peng and other staff at the Lee Kong Chian Natural History Museum, NUS, for their assistance in accessing specimen collections. We thank Chris Yarnes from the University of California Davis for help with sample analysis.