Viverra tangalunga, Gray, 1832

Veron, Geraldine, Willsch, Maraike, Dacosta, Victor, Patou, Marie-Lilith, Seymour, Adrian, Bonillo, Celine, Couloux, Arnaud, Wong, Siew Te, Jennings, Andrew P., Fickel, Jörns & Wilting, Andreas, 2014, The distribution of the Malay civet Viverra tangalunga (Carnivora: Viverridae) across Southeast Asia: natural or human-mediated dispersal?, Zoological Journal of the Linnean Society 170 (4), pp. 917-932 : 925-926

VIVERRA TANGALUNGA

The highest genetic diversity of V. tangalunga was found within the Bornean population. Bornean individuals were present in all major clades, and they shared haplotypes with most of the individuals from other parts of the species’ range. In addition, the wide base of the Borneo haplotypic mismatch distribution supported an ancient status of the Bornean population. These findings are congruent with the presence of Pleistocene V. tangalunga fossils from the Niah Caves on Borneo ( Cranbrook & Piper, 2007; Cranbrook, 2010) and the lack of V. tangalunga fossils elsewhere ( Hooijer, 1962; de Vos, 1983; Tougard, 2001; Louys, 2007), while fossil remains of other viverrids have been found throughout Southeast Asia ( Hooijer, 1962; Flannery et al., 1995; Tougard, 2001; Louys, 2007; van den Bergh et al., 2009; A.M. Moigne pers. comm.). Thus, both genetic and fossil evidence point towards Borneo as the ancestral origin of the current populations of V. tangalunga . This indicates that during the Plio- and Pleistocene there was either a spatial restriction of V. tangalunga to Borneo, followed by a recent expansion to other parts of its range (congruent with the low intraspecific genetic variation within V. tangalunga ), or that populations on other islands became extinct.

The spatial restriction of V. tangalunga within the Sundaic region, during periods of lower sea levels, could have been ecologically driven, as this species depends on forested habitats ( Jennings & Veron, 2011). During drier and cooler periods of the Pleistocene, humid tropical forest areas receded on the Sunda Shelf ( Heaney, 1991; Wurster et al., 2010, but see Cannon, Morley & Bush, 2009), thereby restricting rainforest-dwelling species to forest refugia, and hindering their dispersal across exposed land bridges lacking rainforest. Climate and vegetation simulations ( Cannon et al., 2009), as well as analyses of the carbon isotope composition of ancient cave guano profiles ( Wurster et al., 2010), have suggested that during glacial periods, forests remained present in western Sumatra, central Borneo, and other parts of the emergent Sunda Shelf, and that some of these forested areas could have functioned as refugia for forest-dependent species ( Lohman et al., 2011). Forest contractions during glaciations are likely to have had a more negative impact on V. tangalunga populations within the forest refugia on Sumatra and Peninsular Malaysia (than on Borneo), because of their smaller size during glacial periods ( Slik et al., 2011). The size of forest fragments has been shown to impact the survival rates of species ( Opdam, 1991). In addition, as rainforest refugia have largely been restricted to mountains ( Lohman et al., 2011), the distribution range of lowland species, such as V. tangalunga , may have been more constricted during the last glacial maximum (LGM).

Another explanation for a possible range restriction of V. tangalunga to Borneo during the last glacial period could have been the impact of the Toba supereruption in northern Sumatra in the Late Pleistocene, c. 73 500 years ago ( Ambrose, 1998; Williams et al., 2009; Wilting et al., 2012), although the severity of its impact is debated ( Louys, 2007). On Sumatra and Peninsular Malaysia, this eruption might have resulted in local population extinctions of V. tangalunga . The lack of ash layers on Borneo suggests that this island was less affected by the consequences of this super-eruption ( Oppenheimer, 2002).