doi:10.1038/nindia.2016.131 Published online 4 October 2016
A new species of pika – a rabbit-like herbivore half its size – has recently been discovered in the Sikkim Himalayas1. Named Ochotona sikimaria by scientists who found it, this variety of pika was earlier classified as a sub-species of Ochotona thibetana due to their close resemblance.
While trying to study the impact of climate change on Himalayan biota in 2010, the researchers realised that there wasn’t enough reliable information about pikas. They set out to classify and name the available species correctly – a quest which eventually led to the identification of O. sikimaria as a new species.
The researchers analysed the morphological features of the two species to find that their auditory bullae differed in size. Also, the distance between the two auditory bullae varied between O. thibetana and O. sikimaria. They finally analysed DNA extracted from fecal pellets of both species to be sure that O. sikimaria was indeed a new species.
“In such close cases, genetics is a more reliable way to identify species”, says Uma Ramakrishnan, one of the researchers from the National Centre for Biological Sciences (NCBS), Bangalore. The scientists also probed deeper into O. sikimaria's habitat, which was isolated from that of the members of thibetana. “This isolation over the evolutionary time scale has probably led to its genetic distinction from O. thibetana, with minimal morphological divergence,” says Nishma Dahal, one of the researchers.
Of the 28 species of Pika reported worldwide, 26 are found in Asia and five in the eastern Himalayan region alone. They are adapted to high-elevation and cold environments. “Apart from their ecological role, pikas are also considered indicators of climate change. They have often been called ‘canary on the coal mine’ by researchers in North America studying their vulnerability to rise in global temperature,” Dahal adds.
1. Dahal, N. et al. Genetics, morphology and ecology reveal a cryptic pika lineage in the Sikkim Himalaya. Mol. Phylogenet. Evol. 106, 55-60 (2016) doi: 10.1016/j.ympev.2016.09.015