The Cats of Indochina & Sundaland

The recent and rapid radiation of major felid lineages occurred approximately 10mya, coinciding with the fluctuating geological and climatological conditions in South-East Asia at the time. This dynamic history of South-East Asia produced a complex and highly diverse range of ecosystems in the Indochinese-Sundaic region (see figure 1).12 of the 37 known cats species have emerged from this area, making it the most felid-rich region in the world (Luo et.al. 2014). An investigation by Luo et.al (2014) compared the phylogeny of six felid species from the region by using multiple loci from mitochondrial DNA (mtDNA) and nuclear DNA. They found that the central Thai-Malay Peninsula served as a biogeographic boundary and that there was significant phylogenetic partitions within all species, except the leopard, between Indochina and Sundaland (Luo et.al. 2014). Deep Indochinese-Sundaic divergences around 2mya in the leopard cat and the marbled cat were revealed by mtDNA and nuclear DNA. This was most likely due to serial sea level rises during the late Pliocene and early Pleistocene in addition to the repeated isolation events associated with the environmental changes occurring throughout the Pleistocene (Luo et.al. 2014).


Figure 1. Biogeographic Divisions of South-East Asia (Luo et.al. 2014).

 

They also found that tigers and Asian golden cats showed Indochinese-Sundaic divergences more recently at approximately 72-108kya and 250kya-1.57mya respectively. Curiously, the differentiation in these species was significant for mtDNA but not for nuclear DNA (Luo et.al. 2014). They studied the population genetic structure of tigers (Panthera tigris) which lead to the recognition of tigers on the Thai-Malay Peninsula as a distinct subspecies, the Malayan tiger or P. t. jacksoni. Furthermore they discovered that the Sundaic clouded leopard has been a distinct species from the Indochinese clouded leopard for about 1-1.5mya, recently identifying it as Neofelis diardi (Luo et.al. 2014). The smaller cat species showed higher genetic variability than the tiger and leopard species, especially the leopard cat which has among the highest genetic variability in the Felidae family. The tiger has a very low nuclear DNA diversity demonstrating that tigers came from a very recent common ancestor after genetic homogenization around 72-108kya (Luo et.al. 2014). This gives all the more reason to further conserve and research felid species in the species-rich hotspot of South-East Asia.

References:
  • Luo, S, Zang, Y, Johnson, WE, Miao, L, Martelli, P, Antunes, A, Smith, JLD & O’Brien, SJ 2014, 'Sympatric Asian felid phylogeography reveals a major Indochinese–Sundaic divergence', Molecular Ecology, vol. 23, pp. 2072-2092.
     

Comments

  1. Tasmin4 June 2015 at 16:43

    Thanks for enlightening me into the evolution of the cats. It's been interesting reading about how the different species came to be.

    ReplyDelete

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