Phylogenetic insights on the delineation of Mysore and Malabar subspecies of the Grey Slender Loris Loris lydekkerianus in southern India

Abstract

Slender lorises are a threatened genus of small and nocturnal strepsirrhine primates confined to India and Sri Lanka. The Grey Slender Loris Loris lydekkerianus is divided into several subspecies based on morphological variation and geographical distribution but not supported by molecular data. We investigated the phylogenetic divergence of two subspecies of the Grey Slender Loris in southern India: the Mysore Slender Loris Loris lydekkerianus ssp. lydekkerianus and the Malabar Slender Loris Loris lydekkerianus ssp. malabaricus. We generated whole genome shotgun sequence data and assembled the whole mitochondrial genomes of representative individuals from their distribution in southern India and compared them with publicly available mitogenomes of other lorises. We found that the Mysore and Malabar Slender Lorises vary by 2.09% in the COX1 and CYTB gene regions. Further, phylogenetic analysis of 13 protein-coding and two ribosomal RNA genes in the mitochondrial genome showed that the Mysore and Malabar Slender Lorises form distinct monophyletic clades that diverged about 1.049 million years ago, shortly after the divergence of Red Slender Loris Loris tardigradus. Considering this relatively high sequence variation and evolutionary divergence together with their already established morphological differences and geographically distinct habitats, we propose to recognize the Mysore and Malabar Slender Lorises as two distinct species Loris lydekkerianus and Loris malabaricus.