Sahyadria, a new genus of barbs (Teleostei: Cyprinidae) from Western Ghats of India

Rajeev Raghavan ¹, Siby Philip ², AnvarAli ³ & Neelesh Dahanukar⁴

^1,2,3 Conservation Research Group (CRG), St. Albert’s College, Banerji Road, Kochi, Kerala 682018, India

² Department of Zoology, Nirmalagiri College, Nirmalagiri (P.O), Kannur, Kerala 670701, India

⁴ Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India

^1,4 Zoo Outreach Organization, 96 Kumudham Nagar, VilankurichiRoad, Coimbatore, Tamil Nadu 641035, India

¹ rajeevraq@hotmail.com (corresponding author), ² siby@conservationresearchgroup.org, ³ anvaraliif@gmail.com,⁴n.dahanukar@iiserpune.ac.in

Abstract: Redline Torpedo Barbs (Teleostei: Cyprinidae), comprising of two species, Puntius denisonii and P. chalakkudiensis, and six evolutionarily distinct lineages are endemic to the streams of the Western Ghats freshwater ecoregion in peninsular India. Based on molecular and osteological evidence, we demonstrate that these barbs comprise a distinct genus, for which we propose the name Sahyadria.

Keywords: Cypriniformes, freshwater fish, Puntius denisonii, Puntius chalakkudiensis, taxonomy.

doi: http://dx.doi.org/10.11609/JoTT.o3673.4932-8 | ZooBank:urn:lsid:zoobank.org:pub:ECAD0467-A6C7-4151-B4B3-66017B7B1159

Editor: Anjana Silva, RajarataUniversity of Sri Lanka, Saliyapura, Sri Lanka. Date of publication: 26 November 2013 (online & print)

Manuscript details: Ms # o3673 | Received 22 June 2013 | Final received 02 November 2013 | Finally accepted 13 November 2013

Citation: Raghavan, R., S. Philip, A. Ali & N. Dahanukar (2013). Sahyadria, a new genus of barbs (Teleostei:Cyprinidae) from Western Ghats of India. Journal of Threatened Taxa 5(15): 4932–4938; http://dx.doi.org/10.11609/JoTT.o3673.4932-8

Copyright: © Raghavan et al. 2013. Creative Commons Attribution 3.0 Unported License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Funding: Rajeev Raghavan is supported by the Critical Ecosystem Partnership Fund (CEPF) - Western Ghats Program, and the North of England Zoological Society (NEZS), Chester Zoo, UK. Neelesh Dahanukaris supported by the DST Inspire Faculty Fellowship of the Department of Science and Technology, Government of India.

Competing Interest: The authors declare no competing interests. Funders had no role in study design, data collection, results interpretation and manuscript writing.

Author contributions: All authors contributed equally to the manuscript.

Author Details: Rajeev Raghavan is interested in interdisciplinary research focused on generating information and developing methods to support conservation decision-making, especially in freshwater ecosystems. Siby Philipis interested in molecular phylogenetics, evolution and biogeography of freshwater fishes of the South Asia region. Anvar Ali is interested in taxonomy and systematics of freshwater fishes of the Western Ghats. Neelesh Dahanukar works in ecology and evolutionary biology with an emphasis on mathematical and statistical analysis. He is also interested in taxonomy, distribution patterns and molecular phylogeny of freshwater fishes and amphibians.

Acknowledgements: The authors thank Sanjay Molur for his continuous support and encouragement; Mandar Paingankar for help with osteologicalstudies, and Unmesh Katwatefor photographs. Rajeev Raghavan thanks Ralf Britz and Jörg Freyhof for photographs and useful discussions, Oliver Crimmen for his help during visits to the Natural History Museum (NHM), London, Helmut Wellendorf (Natural History Museum, Vienna) for photographs, and AmbilyNair for her help and support. Siby Philip thanks Mark McGrouther and Rohan Pethiyagoda (Australian Museum, Sydney) for photograph and measurements of the syntype. The authors also thank Lukas Rüber, three anonymous reviewers, and the subject editor for their critical comments and suggestions on the manuscript.

This article forms part of a special series on the Western Ghats of India, disseminating the results of work supported by the Critical Ecosystem Partnership Fund (CEPF), a joint initiative of l’Agence Française de Développement, Conservation International, the European Commission, the Global Environment Facility, the Government of Japan, the MacArthur Foundation and the World Bank. A fundamental goal of CEPF is to ensure civil society is engaged in biodiversity conservation. Implementation of the CEPF investment program in the Western Ghats is led and coordinated by the Ashoka Trust for Research in Ecology and the Environment (ATREE).

For figures, images, tables -- click here

INTRODUCTION

The Redline Torpedo Barbs, presently placed under the polyphyletic genus Puntius Hamilton, 1822 (Teleostei: Cyprinidae), are represented by two species, Puntius denisonii (Day, 1865), its look alike P. chalakkudiensis Menon, Rema Devi & Thobias, 1999, (Images 1,2,3), and, six evolutionarily distinct lineages (John et al. 2013). Endemic to the rivers of the Western Ghats freshwater ecoregion in peninsular India, these barbs are extremely popular in the aquarium trade with more than 300,000 individuals collected from the wild and exported via airports in the last six years (Raghavan et al. 2013). Both P. denisoniiand P. chalakkudiensis are also listed as ‘Endangered’ in the IUCN Red List of Threatened Species due to their restricted range, ongoing population decline, and deterioration of the quality of their habitats (Ali et al. 2011; Raghavan& Ali 2011).

In spite of this popularity and conservation significance, the taxonomy and systematics of these barbs, especially their generic allocation, has been rather uncertain. Since its description, P. denisonii has been placed under several genera including Labeo (Day, 1865 p.299), Puntius (Day, 1865 p.212; Jayaram, 1981, p.100), Barbus (Günther, 1868, p.146; Day, 1878, p.573; 1889, p.320) and Hypselobarbus(Rema Devi et al., 2005, p.1810). Very recently, Pethiyagodaet al. (2012) suggested that P. denisonii and P.chalakkudiensis warrant placement in a separate genus due to the strikingly different coloration and mouth shape compared to all other congeners.

Here, based on osteological and molecular evidence, we demonstrate that the Redline Torpedo Barbs comprise a distinct genus, for which we propose the name Sahyadria.

Materials and Methods

Osteological descriptions are based on a cleared and stained specimen (CRG-SAC.2009.21.7) following the methods described in Potthoff (1984). Conway (2011) was followed for osteologicalnomenclature, and the results compared with published data of related genera (Dawkinsia, Haludaria,Pethia, Puntiusand Systomus; see Pethiyagodaet al. 2012; Pethiyagoda 2013).

The DNA sequences (mitochondrial 16S rRNA and Cytochrome b gene/cytb) were downloaded from NCBI GenBankand used in conjunction with a dataset from an earlier study (Pethiyagoda et al. 2012). These were subsequently used to build the phylogenetic trees, check for monophyly and determine the generic status of these barbs. Sequences were aligned using MUSCLE (Edgar 2004). Protein coding gene (cytb) sequences were translated, aligned, and back-translated prior to the downstream analyses. Tree searches were carried out using maximum likelihood (ML) and Bayesian methodologies. Prior to the ML and Bayesian tree searches, the best-fit nucleotide substitution model was selected for the concatenated dataset using MrAIC (Nylander2004). Maximum likelihood searches were carried out using Garli v2.0 (Zwickl 2006), ten runs of two replicates (10 × 2) each were run, and the best tree (with the best likelihood value), was selected. One hundred bootstrap replicates were carried out in Garli v2.0, and the bootstrap values were placed on the nodes of the best ML tree (determined earlier) using the sumtreesprogram from the Dendropy library (Sukumaran & Holder 2010). A Bayesian tree was built in MrBayes v 3.2.1 (Ronquist & Huelsenbeck 2003), and the analysis was performed for 4×10⁵ generations sampling every 100^th tree. Split frequencies between two independent runs of the four chains were used to decide when to stop the analysis. The Bayesian posterior probabilities (pp) were summarized by building a majority rule consensus tree. The ML bootstrap values and the Bayesianpp’s were mapped on the best ML tree recovered earlier. In a second approach, we used sequences from three previously published Cypriniformes phylogeny datasets (Ruberet al. 2007; Pethiyagoda et al. 2012; Dahanukar et al. 2013), and the sequences for the Redline Torpedo Barbs (mentioned above) to build an extended phylogeny to exactly discern the phylogenetic position of the genus within the family Cyprinidae. Maximum likelihood searches were carried out using PHYML (Guindon et al. 2010) and aLRTbranch support (Anisimova & Gascuel2006) values were mapped on the nodes of the phylogeny. The ML phylogeny was used to test for monophyly of the lineage of interest, using Rosenberg’s P(Rosenberg 2007). The average pair wise tree distance among members of the focal species, and the average pairwise tree distance between the members of the focal species versus the members of the next closest clade were also calculated.

Voucher specimens referred to in this study are deposited in the museum of the Conservation Research Group at St. Albert’s College (CRG-SAC), Kochi, India.

RESULTS

Sahyadria gen. nov.

urn:lsid:zoobank.org:act:C96F727E-5224-400F-978D-A49208CAAE58

Type species: Labeo denisonii (Day, 1865).

Diagnosis: A genus of cyprinid fishes (Teleostei: Cyprinidae) differing from all South and Southeast Asian genera of Barbinaeby the combination of characters and character states including: adult size ranging from 85–190 mm SL; one pair of maxillary barbels; dorsal fin with iii-iv unbranched and eight branched rays, where the last branched ray can be bifurcated right at the base giving appearance of the 9^th branched ray; anal fin with ii-iii unbranched and five branched rays; last unbrancheddorsal-fin ray weak, apically segmented, not serrated (Fig. 1c); lateral line complete, with 26–28 pored scales on the body; free uroneuralabsent (Fig. 1d); gill rakers simple, acuminate (not branched or laminate), in two rows with 12 and 18 rakersrespectively; antrorse predorsal spinous ray absent; a post-epiphysial fontanelle absent (Fig. 1b); supraneuralsfive; infraorbital IO3 slender not overlapping preoperculum (Fig. 1a); pharyngeal teeth 5+3+2; 16 abdominal and 11 caudal vertebrae; and a distinct colorpattern (Image 3a,b) with a wide blackish lateral stripe from snout to the base of caudal fin, black line along the lateral line, and scarlet stripe starting from snout until the mid body (varying by the species) above the black stripe. A yellow stripe present between the black and the scarlet stripes; starting from behind the operculum and ending at the hypural region. Caudal fin lobes with oblique black bands covering the posterior quarter towards the tip, and subterminal oblique yellow bands. Dorsal fin with or without a black blotch. In juveniles, a scarlet coloration covers half the height of anterior rays of the dorsal fin.

Phylogenetically, Sahyadria gen.nov. formsa monophyletic clade supported by high bootstrap value and Bayesian posterior probability (Fig. 2). The closest genus to Sahyadria is Dawkinsia, their separation also supported by high bootstrap value and Bayesian posterior probability. Further, in an extended analysis (Fig. 3) using three previously published datasets (Ruber et al. 2007; Pethiyagoda et al. 2012; Dahanukaret al. 2013), the phylogenetic position of the new genus Sahyadriais similar to the small dataset (Fig. 2), closest group being Dawkinsia. The test for monophyly, Rosenberg’s P, the chance of obtaining monophyly stochastically, was not significant (Rosenberg’s P = 4.2x10^-4). The intra-clade distance was 0.182 (Sahyadria) and inter-clade distance was 0.317 (Sahyadria vs. Dawkinsia).

Distribution: Genus Sahyadria is endemic to the Western Ghats of India, where they occur in 12 west flowing rivers between 9⁰–12⁰N latitudes.

Etymology

The new genus is named after ‘Sahyadri’, noun, thevernacular name for the Western Ghats mountain ranges; gender feminine.

DISCUSSION

The genus Sahyadria,currently comprises of two species S. denisoniiand S. chalakkudiensis, and six evolutionarily distinct lineages (John et al. 2013) all of which are endemic to the Western Ghats region. In their revision of South Asian fishes referred to as Puntius, Pethiyagoda et al. (2012) tentatively placed the Redline Torpedo Barbs under the genus Puntius. However, they mentioned that the two species have a “strikingly different coloration and mouth shape to all other congeners and are likely to warrant placement in a separate genus in the future”.

Sahyadria can be differentiated from its closest sister taxa, Dawkinsia by slender frontal (vs. broader frontal), infraorbital IO3 larger than IO4 (vs. almost equal sized IO3 and IO4), IO4 short (vs. elongated), free uroneural absent (vs. present), presence of 16 abdominal and 11 caudal vertebrae (vs. 15 abdominal and 14–17 caudal vertebrae) and 26–28 lateral line scales (vs. 18–22). These two genera are also morphologically different (Image 3a,b,c,d) where Sahyadria has a pointed snout projecting beyond mouth, while Dawkinsia has a blunt snout and terminal mouth. The color pattern of the two genera is also distinctly different.

Sahyadria differs from the generic characters diagnosing Puntius in having broad and stout IO5 and IO4 (vs. large and slender), absence of post-epiphysial fontanelle (vs. present), absence of free uroneural (vs. present) and having 16 abdominal and 11 caudal vertebrae (vs. 12–14 abdominal and 14–16 caudal vertebrae). Additionally, from Puntius bimaculatus, which also lacks the presence of post-epiphysial fontanelle, Sahyadriadiffers in pre-opercle non overlapping (vs. overlapping), frontal long and slender (vs. short and stout), presence of eight branched rays in the dorsal fin (vs. 7).

Sahyadria differs from Haludariain pre-opercle non overlapping(vs. overlapping), elongated frontal (vs. short and stout), absence of rostral barbels (vs. presence). Sahyadriaalso substantially differs from Haludaria in the long and pointed head structure (Image 3a,b,e). Morphologically, Sahyadria has a long and slender caudal peduncle (vs. deep and short) and having a pointed snout projecting beyond mouth (vs. terminal mouth) (Image 3a,b,f). The colorpattern in the two genera is also different.

Sahyadria can be differentiated from Pethiaand Systomus based on the most prominent character of the last unbranched dorsal fin ray being non osseous and non serrated (vs. osseous and serrated). Sahyadriadiffers from Pethia in having 16 abdominal and 11 caudal vertebrae (vs. 11–13 abdominal and 13–16 caudal vertebrae) and 26-28 lateral line scales (vs. 19–24). Sahyadriaalso differs from Systomus in the absence of free uroneural (vs. presence), absence of rostral barbels (vs. presence) and 16 abdominal and 11 caudal vertebrae (vs. 14–15 abdominal and 17–19 caudal vertebrae).

The phylogenetic tree (Fig. 2) retrieves a monophyletic group comprising all the Redline Torpedo Barbs collected throughout its range. Except for the position of Puntius bimaculatus,our phylogeny resembles that of Pethiyagoda et al. (2012). An additional extended phylogeny with three previously published datasets (Ruberet al. 2007; Pethiyagoda et al. 2012; Dahanukar et al. 2013) in conjunction with the Sahyadria sequences revealed that its phylogenetic position was within Barbinae and that the closest genus was Dawkinsia. The Rosenberg’s P value to test for monophyly (P-value <0.05) clearly showed that the clade (Sahyadria) was indeed distinct with clear separation from its sister group, the genus Dawkinsia. The tests for intra and inter-clade differentiation also pointed towards ample separation between the two groups and supported the reciprocal monophyly of both clades. Larger intra-clade distance values point towards higher diversity in the clade, and a higher inter-clade diversity shows that the two clades in comparison are increasingly distinct. The intra/inter ratio (0.57 in the case of Sahyadria vs. Dawkinsia) is another pointer towards the distinctness of the clades, where smaller values points towards smaller differentiation between the individuals of the focal clade than the differentiation between the two tested clades.

Our study thus clearly demonstrates the separation of Redline Torpedo Barbs from its congeners and its monophyly, thus warranting its placement into a new genus Sahyadria.

References

Ali, A., N. Dahanukar & R. Raghavan (2011). Puntius denisonii. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. <www.iucnredlist.org>. Downloaded on 04 October 2012.

Anisimova, M. & O. Gascuel (2006). Approximate likelihood-ratio test for branches: A fast, accurate, and powerful alternative. Systematic Biology 55(4): 539–552; http://dx.doi.org/10.1080/10635150600755453

Conway, K.W. (2011). Osteology of the South Asian genus Psilorhynchus McClelland, 1839 Teleostei: Ostariophysi: Psilorhynchidae), with investigation of its phylogenetic relationships within the order Cypriniformes. Zoological Journal of the Linnean Society 163: 150-154; http://dx.doi.org/10.1111/j.1096-3642.2011.00698.x

Dahanukar, N., S. Philip, K. Krishnakumar, A. Ali & R. Raghavan (2013). The phylogenetic position of Lepidopygopsis typus (Teleostei: Cyprinidae), a monotypic freshwater fish endemic to the Western Ghats of India. Zootaxa3700(1): 113–139; http://dx.doi.org/10.11646/zootaxa.3700.1.4

Day, F. (1865). On the fishes of Cochin, on the Malabar Coast of India - Part II. Anacanthini.Proceedings of the Zoological Society of London1865(1): 286–318.

Day, F. (1878). The Fishes of India; Being a Natural History of the Fishes Known to Inhabit the Seas and Fresh Waters of India, Burma, and Ceylon Part 4. Quaritsch, London, i-xx+553–779, pls. 139–195.

Day, F. (1889). Fishes. In: Blanford, W.T. (ed.) The Fauna of British India, including Ceylon and Burma. Taylor & Francis, London, v.1: i–xviii+ 1–548pp.

Edgar, R.C. (2004). MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research 32: 1792–1797; http://dx.doi.org/10.1093/nar/gkh340

Guindon, S., J.F. Dufayard, V. Lefort, M. Anisimova, W. Hordijk, & O. Gascuel (2010). New algorithms and methods to estimate maximum-likelihood phylogenies: assessing the performance of PhyML 3.0. Systematic Biology 59(3): 307–321; http://dx.doi.org/10.1093/sysbio/syq010

Gůnther, A. (1868). Catalogue of the fishes in the British Museum. Catalogue of the Physostomi, containing the families Heteropygii, Cyprinidae, Gonorhynchidae, Hyodontidae, Osteoglossidae, Clupeidae,... [thru]...Halosauridae, in the collection of the British Museum. v. 7: i–xx+1–512pp.

Jayaram, K.C. (1981). The Freshwater Fishes of India, Pakistan, Bangladesh, Burma and Sri Lanka - A Handbook. Zoological Survey of India. i–xxii+1–475pp, pls. 1–13.

John, L., S. Philip, N. Dahanukar, A. Ali, J. Tharian, R. Raghavan& A. Antunes (2013). Morphological and genetic evidence for multiple evolutionary distinct lineages in the endangered Red-lined Torpedo Barbs - highly exploited freshwater fishes endemic to the Western Ghats Hotspot, India.PLoS ONE 8(7): e69741; http://dx.doi.org/10.1371/journal.pone.0069741

Menon, A.G.K., K. Rema Devi & M.P. Thobias (1999). Puntius chalakkudiensis, a new colourful species of Puntius (family: Cyprinidae) fish from kerala, south India. Records of the Zoological Survey of India 97(4): 61–63.

Nylander, J.A.A. (2004). MrAIC.pl. Program distributed by the author. Evolutionary Biology Centre, Uppsala University.

Pethiyagoda, R. (2013). Haludaria, a replacement generic name forDravidia (Teleostei:Cyprinidae). Zootaxa 3646: 199; http://dx.doi.org/10.11646/zootaxa.3646.2.9

Pethiyagoda, R., M. Meegaskumbura & K. Maduwage(2012). A synopsis of the South Asian fishes referred to Puntius (Pisces: Cyprinidae). Ichthyological Explorations of Freshwaters 23(1): 69–95.

Potthoff, T. (1984). Clearing and staining techniques, pp. 35–37. In: Moser, H.G., W.J. Richards, D.M. Cohen, M.P. Fahay, A.W. Kendall, Jr. & S.L. Richardson (eds.). Ontogeny and Systematics of Fishes. American Society for Ichthyology and Herpetology, Special Publication No. 1, 760pp.

Raghavan, R., N. Dahanukar, M. Tlusty, A. Rhyne, K. Krishnakumar, S. Molur & A. Rosser (2013). Uncovering an obscure trade: threatened freshwater fishes and the aquarium pet markets. Biological Conservation 164: 158–169; http://dx.doi.org/10.1016/j.biocon.2013.04.019

Raghavan, R. & A. Ali (2011). Puntius chalakkudiensis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. <www.iucnredlist.org>. Downloaded on 04 October 2012.

Rema Devi, K., T.J. Indra, M.B. Raghunathan & M.S. Ravichandran(2005). Fish fauna of the Anamalai hill ranges, Western Ghats, India. Zoos’ Print Journal 20(3): 1809–1811; http://dx.doi.org/10.11609/JoTT.ZPJ.1164a.1809-11

Ronquist, F. & J.P. Huelsenbeck (2003). MRBAYES 3: Bayesian phylogenetic inference under mixed models. Bioinformatics 19: 1572–1574; http://dx.doi.org/10.1093/bioinformatics/btg180

Rosenberg, N.A. (2007). Statistical tests for taxonomic distinctiveness from observations of monophyly. Evolution 61: 317–323; http://dx.doi.org/10.1111/j.1558-5646.2007.00023.x

Rüber, L., M. Kottelat, H.H. Tan, P.K. Ng, & R. Britz(2007). Evolution of miniaturization and the phylogenetic position of Paedocypris, comprising the world’s smallest vertebrate. BMC Evolutionary Biology7(1): 38; http://dx.doi.org/10.1186/1471-2148-7-38

Sukumaran, J. & M.T. Holder (2010). DendroPy: a Python library for phylogenetic computing. Bioinformatics26(12): 1569–1571; http://dx.doi.org/10.1093/bioinformatics/btq228

Zwickl, D.J. (2006). Genetic algorithm approaches for the phylogenetic analysis of large biological sequence datasets under the maximum likelihood criterion. PhD Dissertation. The University of Texas at Austin.