Morphological and molecular divergence of subspecies of Indian Bush Rats, Golunda ellioti Gray, 1837 (Rodentia: Muridae) from Sri Lanka

Genus Golunda is comprised of a single species of small bush rat endemic to southern Asia. In Sri Lanka, two subspecies are recognized, Golunda ellioti ellioti (Indian bush rat) and G. e. nuwara (Ceylon bush rat). These two subspecies can be differentiated by their tail length (longer in G. e. ellioti vs shorter in G. e. nuwara) fur type (short, harsh, spinous in G. e. ellioti vs long, soft and moderately fine in G. e. nuwara), colour of ventral pelage (light grey in G. e. ellioti vs bluish grey in G. e. nuwara) and microscopic hair anatomy (broader and shorter Guard Hair 1 with triangular and square shaped cross sections at the tip of the shield in G. e. ellioti vs narrower and longer Guard Hair 1 with circular to oval shaped cross sections in G. e. nuwara). In the present study, the divergence between the two subspecies was further evaluated using morphology (external and cranial) and molecular data (cytochrome-b, 16S and Rag 1 genes). We found that the brain case was comparatively rounded in G. e. ellioti and the interparietal bone was elongated in G. e. nuwara. Genetic distance between the two subspecies remain at subspecies level; 1.2% for cytochrome-b.