Tuesday, August 22, 2017

[Herpetology • 2017] Nasikabatrachus bhupathi • A New Species of the Genus Nasikabatrachus (Anura, Nasikabatrachidae) from the eastern Slopes of the Western Ghats, India


Nasikabatrachus bhupathi 
Janani, Vasudevan, Prendini, Dutta & Aggarwal, 2017 

We describe a new species of the endemic frog genus Nasikabatrachus, from the eastern slopes of the Western Ghats, in India. The new species is morphologically, acoustically and genetically distinct from N. sahyadrensis. Computed tomography scans of both species revealed diagnostic osteological differences, particularly in the vertebral column. Male advertisement call analysis also showed the two species to be distinct. A phenological difference in breeding season exists between the new species (which breeds during the northeast monsoon season; October to December), and its sister species (which breeds during the southwest monsoon; May to August). The new species shows 6 % genetic divergence (K2P) at mitochondrial 16S rRNA (1330 bp) partial gene from its congener, indicating clear differentiation within Nasikabatrachus. Speciation within this fossorial lineage is hypothesized to have been caused by phenological shift in breeding during different monsoon seasons—the northeast monsoon in the new species versus southwest monsoon in N. sahyadrensis. It is postulated that proximate triggers of breeding behavior and highly stenotopic adaptation of Nasikabatrachus tadpoles to inhabit cascades during monsoonal stream flows, have led to allopatry on the eastern and western slopes of the Western Ghats, thereby promoting speciation in this ancient genus.

Figure 3. Holotype of Nasikabatrachus bhupathi. (a) dorsolateral view; (b) anterior view of head showing fleshy protuberance on the snout; (c) underside of foot, showing hypertrophied shovel-shaped inner metatarsal tubercle; (d) underside of hand showing palmar tubercles.

Nasikabatrachus bhupathi sp. nov.

Etymology: The species epithet commemorates Dr. S. Bhupathy, a noted scientist and a field herpetologist, who passed away due to an ill-fated accident while conducting herpetological surveys in Agasthyamalai, Western Ghats on April 28, 2014.





Figure 10. External morphology of tadpoles of Nasikabatrachus bhupathi.
 (a) dorsal view; (b) ventral view at stage 36, with developing hind limbs, vent tube still present; (c) dorsal view at stage 41, with completely developed hind limbs and visible forelimb bud; (d) dorsal view at stage 42, with both forelimbs erupted; (e) ventral view at stage 42, where one of the forelimbs had erupted completely and the other is yet to erupt, absence of vent tube; (f) dorsal view at stage 43, with transforming snout; (gci) stage 44¢45, showing ventral and dorsal side, transforming oral disc and tail stub; (j) developed imago showing pigmentation pattern of brown and black mottles.


   

S. Jegath Janani, Karthikeyan Vasudevan, Elizabeth Prendini, Sushil Kumar Dutta and Ramesh K. Aggarwal. 2017. A New Species of the Genus Nasikabatrachus (Anura, Nasikabatrachidae) from the eastern Slopes of the Western Ghats, India. Alytes. 34: 1-19.
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