Accepted by B. Sket: 23 Jun. 2016; published: 27 Jul. 2016 287 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2016 Magnolia Press Zootaxa 4144 (2): 287–290 http://www.mapress.com/j/zt/ Correspondence http://doi.org/10.11646/zootaxa.4144.2.10 http://zoobank.org/urn:lsid:zoobank.org:pub:ECA6C88F-05E4-4B56-93EF-C70AB9454FA0 The first data on species diversity of leeches (Hirudinea) in the Irtysh River Basin, East Kazakhstan IRINA A. KAYGORODOVA 1,2 & LYUDMILA I. FEDOROVA 3 1 Limnological Institute, Siberian Branch of Russian Academy of Sciences, 3 Ulan-Batorskaya Street, 664033 Irkutsk, Russia. E-mail: irina@lin.irk.ru 2 Irkutsk State University, 5 Sukhe Bator Street, 664003, Russia 3 Irkutsk State Agrarian University named after A.A. Ezhevsky, 59 Timiryazev Street, 664038 Irkutsk, Russia The Irtysh River is one of the major waterways of the Republic of Kazakhstan. The river originates in the territory of Mongolia and China, flows through the East Kazakhstan and falls into the Ob River in the Western Siberia of Russia. The Kazakhstan section of the river, with length of 1698 km and water resources about 43.8 km 3 (Dyusebaeva 2012), is situated on the border of the West Siberian Plain, the Altai Mountains and the Kazakh Uplands. As the river crosses various natural zones, characteristics of its hydrological regime is very diverse. In the south, in the area of Ust- Kamenogorsk, the valley of the Irtysh extends. In the upper reaches up to the city of Semey (formerly Semipalatinsk), the river is surrounded by plain and mountain landscapes. Downstream from Semey, the Irtysh enters the West Siberian Plain and flows to north-west through dry steppes. The riverbed is unstable: sometimes it is very tortuous, sometimes it is broken into branches, and, there are a lot of sand spits. The hydrological level of the Kazakhstan part of the Irtysh River is regulated with the cascade of storage reservoirs near the towns Bukhtarma, Ust-Kamenogorsk and Shulbinsk. According to expert estimates, the Irtysh runoff has decreased in 3 times for the last decades. The Kazakhstan section of the Irtysh used to be a full-flowing river, with an abundance of fish such as pike, roach, perch, pike-perch, bream, crucian carp, tench, and wild carp. To date, in the Irtysh basin, there is a tension in hydroeconomic and environmental situation, which has occurred due to irrational use and inadequate protection of water resources (Kulikov 2007; Sizov et al. 2010). Shallowing of the river significantly affects biodiversity of aquatic ecosystems. Therefore, it is necessary to conduct comprehensive investigation and monitoring of aquatic communities. However, integrated or targeted studies on hydrobiological diversity have never been performed within the Irtysh River basin. Newly initiated studies of benthic communities in some tributaries of the Irtysh are based mainly on quantitative data of higher taxonomic groups ignoring species composition (Yanygina 2009; Evseeva & Yanygina 2010). Moreover, special-purpose research of hirudofauna within the Upper-Irtysh basin has never been performed previously. There are only scant data on the occurrence of a few leech species in the region. Two species of leeches within the fish parasite fauna have been identified—Piscicola geometra (Linnaeus, 1758) and Caspiobdella fadejewi (Epstein, 1961) (Izumova 1977; Zhumabekova 2009). Subsequently, the presence of P. geometra has been confirmed, and the leech species list has been supplemented by Hemiclepsis marginata (Müller, 1774), Erpobdella octoculata (Linnaeus, 1758) (Deviatkov 2012), and Haemopis sanguisuga (Linnaeus, 1758) (Taylakova & Isakaev 2012). The presence of C. fadejewi is doubtful, since this species was known as a member of the European faunal assemblage with a limited distribution area in the basins of the rivers that flow into the Azov and Black Seas (Epstein 1987; Nesemann & Nuebert 1999). Its invasion to the Volga basin became to be possible due to penetration through the Volga-Don canal (Zhokhov & Pugacheva 2001; Lapkina et al. 2002). There are no data on its occurrence outside this region. Most likely, the leech species affiliation was incorrectly identified. However, there is no possibility to verify it. Here, we report the first data on leech species diversity of the Kazakhstan part of the Irtysh River. The biological material was collected in the water reservoirs, different parts of the river, including the Semipalatinka natural channel, and in some water bodies of the adjacent area. Morphological analysis of ethanol-fixed samples was performed using a stereomicroscope MSP-2 var. 2 (LOMO). Species affiliation was determined under existing systematic keys (Lukin 1976; Nesemann & Neubert 1999) in accordance with the modern classification of the group. The external morphology of identified annelids was in agreement with relevant species description. The collection of leech species with voucher specimens was deposited at the Limnological Institute, Irkutsk, Russia. As a result, the Irtysh River leech samples were thoroughly analyzed and the first checklist was compiled. The leech