Endemic Indirana Frogs of the Western Ghats Biodiversity Hotspot
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Ann. Zool. Fennici 49: 257–286 ISSN 0003-455X (print), ISSN 1797-2450 (online) Helsinki 30 November 2012 © Finnish Zoological and Botanical Publishing Board 2012 Endemic Indirana frogs of the Western Ghats biodiversity hotspot Abhilash Nair1,*, Sujith V. Gopalan2, Sanil George2, K. Santhosh Kumar2, Amber G. F. Teacher1,3 & Juha Merilä1 1) Ecological Genetics Research Unit, Department of Biosciences, P.O. Box 65, FI-00014 University of Helsinki, Finland (*corresponding author’s e-mail: [email protected]) 2) Chemical Biology, Rajiv Gandhi Centre for Biotechnology, PO Thycaud, Poojappura, Thiruvananthapuram - 695 014, Kerala, India 3) current address: Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Tremough, Penryn, Cornwall TR10 9EZ, UK Received 25 Mar. 2012, final version received 24 July 2012, accepted 21 Sep. 2012 Nair, A., Gopalan, S. V., George, S., Kumar, K. S., Teacher, A. G. F. & Merilä, J. 2012: Endemic Indirana frogs of the Western Ghats biodiversity hotspot. — Ann. Zool. Fennici 49: 257–286. Frogs of the genus Indirana belong to the endemic family Ranixalidae and are found exclusively in the Western Ghats biodiversity hotspot. Since taxonomy, biology and distribution of these frogs are still poorly understood, we conducted a comprehensive literature review of what is known on the taxonomy, morphology, life history characteris- tics and breeding biology of these species. Furthermore, we collected information on the geographical locations mentioned in the literature, and combined this with information from our own field surveys in order to generate detailed distribution maps for each spe- cies. Apart from serving as a useful resource for future research and conservation efforts, this review also highlights the areas where future research efforts should be focussed. Introduction biodiversityhotspots.org), and they are under threat from growing human populations (Cin- The world’s biodiversity is threatened by human cotta et al. 2000). Therefore, it can be argued activities, yet the sustainable use of biodiver- that their protection should be of high priority, as sity is fundamental to the future development they may represent an efficient way of preserv- of humanity (Jenkins 2003). As financial and ing a large proportion of the world’s biodiversity. human resources are limited for nature conserva- Yet, our understanding of the diversity in these tion, it may be appropriate to focus efforts on hotspots remains very poor, and is often limited biodiversity hotspots (Myers et al. 2000, Brooks to species counts of a few key groups of fauna et al. 2002, Roberts et al. 2002). About 34 biodi- and flora. This hampers any rational approach to versity hotspots have been recognised, based on conservation in biodiversity hotspots, and ques- plant and vertebrate species richness, endemism tions any strategy that protects these regions as and threat status. These 34 biodiversity hotspots a surrogate sample of total global biodiversity contain 50% of all plant species and 42% of all (Grenyer et al. 2006). vertebrate species, but these areas comprise only The Western Ghats–Sri Lanka biodiversity 2.3% of all the land surface of the globe (www. hotspot (Bossuyt et al. 2004) is one of the world’s 258 Nair et al. • ANN. ZOOL. FENNICI Vol. 49 recognized biodiversity hotspots (cf. www.biodi- 2001; Table 1). Two of them are classified as versityhotspots.org). The herpetofauna of south- critically endangered (I. gundia and I. phryno- ern India — an area which comprises parts of derma), three as endangered (I. brachytarsus, I. the Western and Eastern Ghats — is one of the diplosticta, and I. leptodactyla), one as vulner- most diverse and poorly known groups in tropi- able (I. leithii), two (I. beddomii and I. semi- cal Asia (Inger 1999). Although many species of palmata) as least concern, and two (I. longicrus amphibians are yet to be described from India and I. tenuilingua) are data deficient (www.iucn. (Aggarwal 2004, Kuramoto et al. 2007), of the org). The populations of all these species are known 284 species (Dinesh et al. 2009), 13 spe- small and isolated, owing to the destruction and cies are at present critically endangered and 31 fragmentation of their natural habitat due to vari- species are endangered (www.iucn.org). These ous anthropogenic activities (Nair 1991), and as facts combined with the realization that amphib- a result these species may face extinctions in the ians comprise a group of organisms facing par- near future (Daniels 1992). ticularly pronounced declines and extinction The current knowledge of the interspecific risks worldwide (Houlahan et al. 2000, Stuart biodiversity, distribution and community struc- et al. 2004, Mendelson et al. 2006), suggest that ture of the Western Ghats amphibians is limited studies into the diversity and conservation biol- (Andrews et al. 2005a, 2005b, 2005c, 2005d), ogy of the Western Ghats amphibians should be therefore it is hardly surprising that very few well motivated. intraspecific studies on the Western Ghats The current knowledge of the amphibian amphibians have, to date, been conducted. As fauna of the Western Ghats is scanty and frag- far as we are aware, only few population genetic mented. All that is known suggests that this studies of amphibians within India have been fauna is unique with high degree of endemism carried out, and most of the genetic studies made (Inger 1999, Biju 2001). Three families, Micrix- at the interspecific level have focused on taxo- alidae, Nasikabatrachidae and Ranixalidae, and nomic questions (e.g. Bossyut & Milinkovitch ten genera are endemic to the Western Ghats. 2000, Kosuch et al. 2001, Wilkinson et al. 2002). The genus Indirana which is the focus of this Except for a few well studied taxa (e.g. Biju & review belongs to the endemic family Ranix- Bossyut 2009), the evolutionary relationships, alidae and comprises of 10 known species (Biju taxonomy and species-level diversity of the West- ern Ghats amphibian fauna are poorly resolved and nothing is known of the extent of genetic Table 1. The ten currently recognized Indirana species variability and differentiation among local popu- with their IUCN statuses and approximate estimates of their distribution ranges (km2). The distribution ranges lations of most of the species. Consequently, were obtained by summing the 50 km2 squares for each there is a high degree of uncertainty about the species (see Fig. 1). taxonomic status (cf. cryptic species) and poten- tial genetic issues (e.g. loss of genetic diversity, Species IUCN status Distribution inbreeding, restrictions to gene flow due to habi- range (km2) tat fragmentation) regarding the local amphibian Indirana beddomii Least concern 1250 populations. From this, it follows that any plans Indirana brachytarsus Endangered 550 for the conservation and management of amphib- Indirana semipalmata Least concern 700 ian biodiversity in this biodiversity hotspot cur- Indirana leithii Vulnerable 500 rently have to be based on educated guesses, Indirana leptodactyla Endangered 600 Indirana diplosticta Endangered 350 rather than on scientifically based knowledge. Indirana gundia* Critically 50 The aim of this review is to provide a com- endangered prehensive and critical literature review bringing Indirana phrynoderma Critically 100 together all available information on the biology endangered of the endemic Indirana frogs from the Western Indirana longicrus* Data deficient 50 Indirana tenuilingua* Data deficient 50 Ghats. By doing so, we wished to create a useful resource and reference for those interested in the *Known from only one locality. biology and conservation of Indirana frogs, as ANN. ZOOL. FENNICI Vol. 49 • Endemic Indirana frogs of the Western Ghats biodiversity hotspot 259 well as to identify knowledge gaps and future losticta, I. leptodactyla and I. phrynoderma), and research needs. Apart from bringing together the National Museum of Natural History in Paris what is known about the morphology, systemat- (MNHN; I. gundia). In addition, we also exam- ics, basic ecology and biology of these frogs, we ined specimens deposited at the Bombay Natural paid particular attention to what is known about History Museum (BNHS), the Zoological Survey the geographical distribution of different species of India in Calicut (ZSI, Western Ghats Regional across the Western Ghats. In order to create puta- Centre), in order to understand how many species tive distribution maps, we used both information are recognized, and on what grounds. Informa- available from literature, and data from field-sur- tion regarding the ecology, breeding biology and veys conducted in different parts of the Western life history was also assimilated from the litera- Ghats between 2008 and 2011. ture and from our own field studies. Methods Biogeography The information presented in this review was Although some distribution maps of different obtained from all possible literature sources Indirana species have been published (e.g. Stuart which were identified by searching the Web of et al. 2008), it is unclear how accurate those maps Knowledge (http://apps.webofknowledge.com), are, as information is typically not given about Google Scholar, and the amphibian databases the data upon which these maps are based. In AmphibiaWeb (www.amphibiaweb.org) and order to gain a visual overview of the distribu- Amphibian Species of the World 5.4 (http:// tion of different Indirana species, we used a dual research.amnh.org/vz/herpetology/amphibia/), strategy. First, we looked for records of Indirana using ‘Indirana’ as a search query. In general, species in the literature and noted the localities these searches produced very few hits (5 hits in as accurately as they were given. The localities Web of Knowledge), and most information was of the frogs mentioned in the literature typically retrieved from books, reports and specific (typi- lack precision, and often describe only a region cally non-refereed) herpetological or zoological as opposed to a precise locality. The impreci- journals. Each time we encountered information sion of the locality information has also been on Indirana frogs in a given source, the refer- discussed by other authors (e.g.