Hiding in plain sight: description of a new species of <i>Nyctibatrachus</i> (Amphibia, Anura, Nyctibatrachidae) from the central Western Ghats, India

Frogs belonging to the genus <i>Nyctibatrachus</i> are endemic to the Western Ghats biodiversity hotspot. They are the second most speciose frogs in the Western Ghats, with 70% of the species having narrow distribution ranges. They are also highly cryptic in nature. In this study, we describe a new species of <i>Nyctibatrachus</i> frog from the central Western Ghats of India. <i>Nyctibatrachus kali</i> sp. nov. is described from the Kali River basin of North Karnataka. The new species is distinguishable from all 34 currently recognised <i>Nyctibatrachus</i> species by a combination of morphological, acoustic and phylogenetic analyses. Molecular phylogeny based on two mitochondrial genes (16S rRNA and ND1) reveals that it belongs to the <i>N. sanctipalustris</i> clade. Based on the analysis of 16S rRNA, <i>Nyctibatrachus kali</i> sp. nov. shows genetic divergence >5% with its congeners, and based on the analysis of ND1, <i>Nyctibatrachus kali</i> sp. nov. shows genetic divergence >10% with its congeners. The bioacoustics analyses indicated that the new species differed from their closest congeners based on the dominant frequency of the advertisement calls and the number of notes in each call. For the first time, we observed two distinct advertisement call categories-call notes with low and high dominant frequency in <i>Nyctibatrachus kali</i> sp. nov. and its congeners. Our study adds to the rich diversity of frogs from the Western Ghats of India.