Wirdateti, H. Tanaka, W.P.B. Putra, Yulianto, M.I. Maulana, K.A.I. Nekaris
Seven slow loris (Nycticebus spp.) are recognised in Indonesia, all of which are globally threatened: greater slow loris (N. coucang), Philippine slow loris (N. menagensis), Sumatran slow loris (N. hilleri), Bangka slow loris (N. bancanus), Bornean slow loris (N. borneanus), Kayan slow loris (N. kayan) and Javan slow loris (N. javanicus). These species were identified by morphology, genetics, or both. Here, we evaluated the diversity of the full region of mitochondrial COI (MT-COI) sequence diversity in three Indonesian slow loris species: N. coucang (n= 20), N. menagensis (n=4) and N. javanicus (n=19). As a result of sequencing, different 18 haplotypes of N. coucang, 4 haplotypes of N. menagensis and 14 haplotypes of N. javanicus were detected. The MT-COI sequences of each “species” were analysed using MEGA, DNAsp, ARLEQUINE, AMOVA, and BEAST to evaluate genetic diversity and divergence time within and between species of slow loris. The lowest pairwise genetic distance was found between N. coucang and N. menagensis (0.04 - 0.06), followed by N. javanicus and N. menagensis (0.05 - 0.11), and N. javanicus and N. coucang (0.05 - 0.12). A phylogenetic tree revealed that N. coucang and N. bengalensis were included in a cluster, whereas N. menagensis and N. javanicus were classified into different clusters. In addition, about 80% of the genetic variation among three slow loris species in Indonesia could be explained by geographic variation. Our results suggest that N. javanicus diverged from other slow loris species at 13.82 Mya (Middle Miocene period). This was followed in the Early Pleistocene period (2.44 Mya), when N. coucang and N. bengalensis were diverged in a different cluster. © 2026 Instituto Internacional de Ecologia. All rights reserved.
National Research and Innovation Agency, Research Center for Biosystematics and Evolution, West Java, Bogor, Indonesia; Kyoto University, Center for Ecological Research, Kanrin, Inuyama, Japan; National Research and Innovation Agency, Research Center for Applied Zoology, West Java, Bogor, Indonesia; Institut Teknologi Sumatera, Faculty of Science, Department of Biology, Lampung, Indonesia; Anglia Ruskin University, School of Life Sciences, Faculty of Science and Engineering, Cambridge, United Kingdom