An integrative approach to infer systematic relationships and define species groups in the shrub frog genus Raorchestes, with description of five new species from the Western Ghats, India

Sonali Garg; Robin Suyesh; Sandeep Das; Mark A Bee; S D Biju

doi:10.7717/peerj.10791

An integrative approach to infer systematic relationships and define species groups in the shrub frog genus Raorchestes, with description of five new species from the Western Ghats, India

PeerJ. 2021 Mar 3:9:e10791. doi: 10.7717/peerj.10791. eCollection 2021.

Authors

Sonali Garg^#¹, Robin Suyesh^#^{1

2}, Sandeep Das^{3

4}, Mark A Bee⁵, S D Biju¹

Affiliations

¹ Systematics Lab, Department of Environmental Studies, University of Delhi, Delhi, India.
² Department of Environmental Studies, Sri Venkateswara College, University of Delhi, Delhi, India.
³ Forest Ecology and Biodiversity Conservation Division, Kerala Forest Research Institute, Peechi, Kerala, India.
⁴ EDGE of Existence programme, Conservation and Policy, Zoological Society of London, London, UK.
⁵ Department of Ecology, Evolution, and Behavior, University of Minnesota - Twin Cities, St. Paul, MN, USA.

^# Contributed equally.

Abstract

The genus Raorchestes is a large radiation of Old World tree frogs for which the Western Ghats in Peninsular India is the major center for origin and diversification. Extensive studies on this group during the past two decades have resolved long-standing taxonomic confusions and uncovered several new species, resulting in a four-fold increase in the number of known Raorchestes frogs from this region. Our ongoing research has revealed another five new species in the genus, formally described as Raorchestes drutaahu sp. nov., Raorchestes kakkayamensis sp. nov., Raorchestes keirasabinae sp. nov., Raorchestes sanjappai sp. nov., and Raorchestes vellikkannan sp. nov., all from the State of Kerala in southern Western Ghats. Based on new collections, we also provide insights on the taxonomic identity of three previously known taxa. Furthermore, since attempts for an up-to-date comprehensive study of this taxonomically challenging genus using multiple integrative taxonomic approaches have been lacking, here we review the systematic affinities of all known Raorchestes species and define 16 species groups based on evidence from multi-gene (2,327 bp) phylogenetic analyses, several morphological characters (including eye colouration and pattern), and acoustic parameters (temporal and spectral properties, as well as calling height). The results of our study present novel insights to facilitate a better working taxonomy for this rather speciose and morphologically conserved radiation of shrub frogs. This will further enable proper field identification, provide momentum for multi-disciplinary studies, as well as assist conservation of one of the most colourful and acoustically diverse frog groups of the Western Ghats biodiversity hotspot.

Keywords: Anura; Bioacoustics; Biodiversity hotspot; Diagnostic characters; Eye colour; Integrative taxonomy; Molecular phylogeny; Morphology; Peninsular India; Rhacophoridae.

Grants and funding

This study was supported by the following grants to S D Biju: Critical Ecosystem partnership Fund, Conservation International, USA (Project 55918/2009); University of Delhi Research and Development Grants 2011–12, 2014–15 and 2015–16; DST Purse Grant Phase I and Phase II, Department of Science and Technology, Ministry of Science and Technology, Government of India. Sonali Garg received fellowships from University of Delhi, University Teaching Assistantship Scheme (2010/56562), and from the Council for Scientific and Industrial Research, Government of India, as Senior Research Fellow (CSIR No. 9/45(1381)/2015-EMR-I) and Research Associate (CSIR No. 09/045(1694)/2019-EMR-I). Sonali Garg was also supported by a small grant from the Andrew Sabin Family Foundation (ASFF)/Global Wildlife Conservation, USA for field studies. Robin Suyesh received Life Sciences (JRF-SRF) fellowship from UGC-CSIR, Government of India (2009–2014) and was supported by Rufford Small Grants for Nature Conservation (2012–2013) and Animal Behaviour Society’s Developing Nations Award (2014) for field studies. Sandeep Das was supported by EDGE Fellowship grant. Mark A Bee was supported by a Fulbright Fellowship. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.