Verlag Dr. Friedrich Pfeil ISSN 0936-9902 Excerpt from Ichthyological Exploration of Freshwaters An international journal for field-orientated ichthyology Volume 24 Number 2 This article may be used for research, teaching and private purposes. Exchange with other researchers is allowed on request only. Any substantial or systematic reproduction, re-distribution, re-selling in any form to anyone, in particular deposition in a library, institutional or private website, or ftp-site for public access, is expressly forbidden. Ichthyological Exploration of Freshwaters An international journal for field-orientated ichthyology Volume 24 • Number 2 • November 2013 pages 97-192, 48 figs., 15 tabs. Managing Editor Maurice Kottelat, Route de la Baroche 12, Case postale 57 CH-2952 Cornol, Switzerland Tel. + 41 32 4623175 · Fax + 41 32 4622259 · E-mail [email protected] Editorial board Ralf Britz, Department of Zoology, The Natural History Museum, London, United Kingdom Sven O. 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Erscheint jährl. viermal. – Aufnahme nach Vol. 1, No. 1 (1990) ISSN 0936-9902 Vol. 1, No. 1 (1990) – Copyright © 2013 by Verlag Dr. Friedrich Pfeil, München, Germany All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Publisher, Verlag Dr. Friedrich Pfeil, Wolfratshauser Str. 27, 81379 München, Germany. Printed by PBtisk a.s., Prˇíbram I – Balonka ISSN 0936-9902 Printed in the European Union Verlag Dr. Friedrich Pfeil, Wolfratshauser Str. 27, 81379 München, Germany Phone + 49 89 742827-0 · Fax + 49 89 7242772 · E-mail: [email protected] · www.pfeil-verlag.de 121 Copyright © Verlag Dr. Friedrich Pfeil Ichthyol. Explor. Freshwaters, Vol. 24, No. 2, pp. 121-140, 8 figs., 4 tabs., November 2013 © 2013 by Verlag Dr. Friedrich Pfeil, München, Germany – ISSN 0936-9902 A review of the danionine genera Rasboroides and Horadandia (Pisces: Cyprinidae), with description of a new species from Sri Lanka Sudesh Batuwita*, **, ***, Madura de Silva** and Udeni Edirisinghe* The taxonomy of Rasboroides and Horadandia, two genera of small danionine cyprinids that occur in southern India and Sri Lanka, is reviewed. Rasboroides comprises four species, distinguished as follows: R. vaterifloris and R. nigromarginatus differ from their congeners by a lesser body depth (26.9-33.0 % SL); and from each other by a greater interorbital width in males (29-33 % HL vs. 17-22) and greater anal-fin depth in females (23.5-24.8 % SL vs. 17.4-22.7) of R. vaterifloris. Rasboroides pallidus differs from R. rohani, new species, by its smaller size (up to 1 1 1 1 1 1 24.6 mm vs. 35.5 mm SL), by possessing fewer scales in transverse line on body (/2 6 /2-/2 7 /2 vs. /2 8 /2) and in lateral series (20-24 vs. 25-28). Rasboroides differs from Horadandia, its sister group, by the presence in males of a series of tubercles on the leading edge of the pectoral fin (absent in Horadandia) and by possessing 3 (vs. 2) rows of pharyngeal teeth, while the pharyngeal teeth of Horadandia are ornamented distally by a series of cusps, a character absent in Rasboroides. Horadandia brittani is recognized as a valid species, distinguished from H. atuko- rali by possessing a smaller eye (eye diameter 27-37 % HL, vs. 37-41) and having the dorsal-fin origin closer to the hypural notch (vs. midway between snout-tip and hypural notch). The genus Rasboroides is restricted to shaded rainforest streams in the south-western ‘wet zone’ (Kalu to Walawe Rivers) of Sri Lanka, whereas Hora- dandia occurs in the coastal floodplains of western Sri Lanka and southern India. Introduction goda, 1991) until Kottelat & Vidthayanon (1993) validated it and elevated it to generic rank. Brittan (1954) created the monotypic subgenus Kottelat & Vidthayanon (1993) also suggested Rasbora (Rasboroides) for Rasbora vaterifloris De- that Rasboroides could be a synonym of Horadan- raniyagala, 1930, which he distinguished from dia, a genus established by Deraniyagala (1943) other Rasborinae mainly by its having an incom- for a diminutive species of cyprinid fish, H. atu- plete lateral line, a deep body, eye diameter korali. Deraniyagala distinguished Horadandia greater than interorbital width and scales cha- from other cyprinid genera mainly by the absence otically arranged. The subgenus, however, was of barbels and a lateral line, 6 branched anal-fin ignored by subsequent authors (e. g., Pethiya- rays, and the pharyngeal-teeth in two rows with * Postgraduate Institute of Agriculture, University of Peradeniya, Sri Lanka. E-mail: [email protected] ** Wildlife Conservation Society Galle, Biodiversity Education and Research Center, Hiyare Reservoir, Hiyare, Galle, Sri Lanka. E-mail: [email protected] *** Corresponding author: E-mail: [email protected] Ichthyol. Explor. Freshwaters, Vol. 24, No. 2 122 Copyright © Verlag Dr. Friedrich Pfeil 4/1 teeth. The genus remained monotypic and Materials and methods restricted to Sri Lanka for almost 50 years until Rema Devi & Menon (1992) described a subspe- Materials referred to in this work are deposited cies, H. a. brittani, from south-western India. in the collection of the Wildlife Heritage Trust of Recent morphological and molecular phylo- Sri Lanka (WHT) now in the National Museum, genetic analyses (Liao et al., 2010; Tang et al., Colombo, Sri Lanka (NMSL), which includes 2010) show H. atukorali and Rasboroides vaterifloris specimens collected in the course of an on-going to be sister taxa, calling for a re-examination of national freshwater-fish survey commissioned by the validity of the latter genus, which Brittan the Department of Wildlife Conservation in 2010; (1954) himself conceded bore “some points of the Natural History Museum, London (BMNH); striking similarity” to Horadandia. the Zoological Museum Hamburg (ZMH); and Meanwhile a further species, Rasboroides nigro- the Wildlife Conservation Society – Galle (WCSG). marginatus Meinken, 1957 (type locality ‘Ceylon’ All material examined in this study is from Sri = Sri Lanka), remained in the synonymy of R. va- Lanka except where otherwise mentioned. terifloris (e. g. see Deraniyagala, 1958; Pethiya- Measurements were made using dial Vernier goda, 1991: 129), though without critical review, callipers to the nearest 0.1 mm. Methods for tak- evidently because its precise locality was un- ing counts and measurements follow Pethiya- known. In 1994, however, as part of an ichthyo- goda & Kottelat (2005). Body scales in transverse logical survey by the Wildlife Heritage Trust line were counted diagonally from the dorsal-fin (WHT), R. Pethiyagoda and K. Manamendra- origin posteroventrad to the scale anterior to the Arachchi had collected 14 specimens of a ‘Rasb- anal-fin origin, with the scales straddling the fin 1 ora’ at Atweltota, which closely matched Mein- origins counted as /2. Standard length (SL) was ken’s original description of R. nigromarginatus. measured from the snout-tip to the hypural notch, This population was independently discovered and head length from snout-tip to the bony edge in 2010 in the course of an expedition by the of the opercle. The dorso-hypural distance was Wildlife Conservation Society, Galle (WCSG). taken as the distance from the base of the ante- Here, as part of an ongoing revision of Sri riormost unbranched dorsal-fin ray to the hypural Lankan and southern Indian Cyprinidae (e. g., notch. Numbers in brackets following a count Silva et al., 2010; Pethiyagoda et al., 2008, 2012) indicate the frequency of that count. we review this group of fishes and (1) show that Specimens for osteological examination were multiple autapomorphies serve to distinguish cleared and stained using alizarin red S following Rasboroides from Horadandia; (2) demonstrate that the procedure of Taylor & Van Dyke (1985). H. brittani and R. nigromarginatus are valid spe- Caudal vertebrae were counted from the first cies; (3) recognize Rasbora vaterifloris var. pallida haemal-spine bearing vertebra to the terminal as a valid species and redescribe it as Rasboroides compound centrum supporting the hypural series. pallidus; and (4) describe Rasboroides rohani, a new Abdominal vertebrae