ISSN: 1683-1489 MRC Technical Paper No.45 April 2015 Identification Handbook of Freshwater Zooplankton of the Mekong River and its Tributaries Report prepared by Mekong River Commission Environment Programme ISSN: 1683-1489 MRC Technical Paper No.45 April 2015 Identification Handbook of Freshwater Zooplankton of the Mekong River and its Tributaries Report prepared by Mekong River Commission Environment Programme Published in Vientiane, Lao PDR in April 2015 by the Mekong River Commission Suggested citation: Phan Doan Dang, Nguyen Van Khoi, Le Thi Nguyet Nga, Dang Ngoc Thanh and Ho Thanh Hai, 2015. Identification Handbook of Freshwater Zooplankton of the Mekong River and its Tributaries, Mekong River Commission, Vientiane. 207pp. The opinions and interpretation expressed within are those of the authors and do not necessarily reflect the views of the Mekong River Commission. Editors: Chavalit Vidthayanon, Henrik Larsen and Nguyen Van Duyen Technical English Editors: Robyn Taylor and Robert Brown Illustrations: Phan Doan Dang Photographers: © Mekong River Commission © Mekong River Commission Office of the Secretariat in Phnom Penh (OSP) 576 National Road, #2, Chak Angre Krom, P.O. Box 623, Phnom Penh, Cambodia Tel. (855-23) 425 353. Fax (855-23) 425 363 Email: [email protected] Office of the Secretariat in Vientiane (OSV) Office of the Chief Executive Officer 184 Fa Ngoum Road, P.O. Box 6101, Vientiane, Lao PDR Tel (856-21) 263 263. Fax (856-21) 263 264 Website: www.mrcmekong.org Table Of Contents AcknowledGments v INTRODUCTION VII 1. MAJOR GROUPS OF FRESHWATER ZOOPLANKTON 1 Key to phyla, classes and orders of the Mekong zooplankton 3 2. PHYLUM SARCOMASTIGOPHORA ¬ SUPERCLASS RHIZOPODA 5 Class Lobosa 8 Order Testacealobosa 8 Class Filosa 15 Order Testacealobosa 15 3. PHYLUM ROTIFERA 17 Class Bdelloidea 21 Order Bdelloida 21 Class Monogononta 22 Order Ploima 23 Order Flosculariaceae 67 4. PHYLUM ARTHROPODA ¬ CLASS BRANCHIOPODA ¬ ORDER CLADOCERA 75 5. PHYLUM ARTHROPODA ¬ CLASS COPEPODA 109 Order Calanoida 114 Order Cyclopoida 154 6. PHYLUM ARTHROPODA ¬ CLASS OSTRACODA 163 Order Podocopida 166 Literature Citations 169 Glossary 177 Plates 179 INDEX 195 Identification of Freshwater Zooplankton of the Mekong River and its Tributaries iii Acknowledgments The authors wish to acknowledge the sentatives from the National Mekong Com- technical and financial support provided by mittees of Cambodia, Lao PDR, Thailand the Environment Programme of the Mekong and Viet Nam, particularly for their help in River Commission Secretariat, special providing specimens and technical review. thanks are conveyed to Mr. Henrik Larsen International Technical Advisor, Mr. Nguyen The authors also wish to thank colleagues Van Duyen, Environment Programme Coor- of the Institute of Tropical Biology, Viet dinator, Ms. Robyn Taylor and Mrs. Hanne Nam, for their technical contribution. Final- Bach for their technical guidance that ly, the authors are indebted to Mr. Russell assisted us to complete this document. Shiel, Mr. Bruce C. Chessman and Mr. Ian Cambell for their critical comments and The authors also express their appreciation suggestions during proof reading of this for the support given to the study by repre- taxonomic context. Identification of Freshwater Zooplankton of the Mekong River and its Tributaries v INTRODUCTION Identification of Freshwater Zooplankton of the Mekong River and its Tributaries vii INTRODUCTION Freshwater zooplankton is one of four producers but they can also indicate envi- selected bioindicators (benthic diatom, ronmental status over a given time. During zooplankton, littoral macroinvertebrate recent years, the diversity, abundance and and benthic macroinvertebrate), uses for tolerance of zooplankton have been used to assessment in Ecological Health Monitoring indicate the deterioration in water quality (EHM) activity of the MRC Member Coun- caused by pollution/eutrophication, orgen- tries since 2003. erally by human impacts. In the first phase of the EHM programme, There have been many studies of different the species identification and nomencla- aspects of zooplankton: natural habitat, ture determination for zooplankton was spatial and temporal distribution, life-cycle carried out by international experts. Many development stages, individual biological taxonomic documents were used but these features, roles, functions and importance in documents only describe the species that aquatic ecosystem and fishery productivity have been found in temperate or tropical and ability to withstand different stress- water bodies elsewhere in the world out- es. To interpret and use these studies, an side the Mekong Basin. A few descriptions important first step is proper identification for species recorded in scattered studies and nomenclatural determination for all in the Mekong Delta were used, although species discovered in water bodies. As these studies are obsoleted. A long-term bi- biologists and ecologists build up collec- ological study and monitoring programme tions of zooplankton, misidentification will for a river and river basin of such size and be reduced; however people working in the international stature as the Mekong needs field will also welcome an addition to the to have more orthodox manual books for literature to help in identification. classifying and identifying the aquatic organisms that are present in the Lower The zooplanktons described in this book Mekong Basin (LMB). belong to the Protozoa, Rotifera and some small groups of crustaceans, such As heterotrophic microinvertebrates, the as Copepoda, Cladocera and Ostracoda. zooplankton play important role in the Some other small groups belonging to the aquatic food web. Zooplankton are found in phylum Protozoa (Flagellata, Euglena) both freshwater and marine environments, have not been described. The specimens many groups can adapt and develop in of zooplankton described in this book were littoral, open or coastal water. These plank- mainly collected in the survey of March tonic organisms not only regulate aquatic 2008 in Thailand, Lao PDR and Viet Nam productivity by their function as secondary (deficient samples in Cambodia). In addi- viii Identification of Freshwater Zooplankton of the Mekong River and its Tributaries INTRODUCTION tion, the identification has been updated All the descriptions following the taxonom- from specimens collected in Viet Nam in ic keys are only preliminary and provide March 2011. Specimens collected in the first essential information to help readers easily phase (2004–2007) have not been included distinguish the differences between species as due to inadequate preserved. and determine more accurately their no- menclature. Almost all the drawings and descriptions for each species are based on the specimens “Identification of Zooplankton of the directly collected in the LMB. For a very few Lower Mekong River and its Tributaries” is species of Copepoda, Cladocera and types a specialized taxonomic document, which of Trophi some species of Rotifera has been has been edited by a group of Vietnamese redraw from other authors. biologists who specialize in the study of zooplankton. They have tried to systemati- The taxonomic keys described in this book cally assemble all the species of zooplankton have mainly been cited from reference found in the lower Mekong River, from MRC’s documents from the United States, India, monitoring programme (March 2008) and China, Japan, Korea, Thailand, Russia, other studies (in Vietnam in March 2011). Germany and Spain. These taxonomic keys MRC hopes the book will assist the national have been presented to follow the grades experts of the Member Countries in environ- of Phylum, Class, Order, Family, Genus and mental health assessment and monitoring Species. For the Protozoa subkingdom only, of the Lower Mekong Basin as well as other taxonomic keys stopped at the genus level. scientists in other fields of study. Identification of Freshwater Zooplankton of the Mekong River and its Tributaries ix CHAPTER 1. MAJOR GROUPS OF FRESHWATER ZOOPLANKTON Identification of Freshwater Zooplankton of the Mekong River and its Tributaries 1 CHAPTER 1. MAJOR GROUPS OF FRESHWATER ZOOPLANKTON According to The International Code of Zoological Nomenclature (ICZN) is the system of rules and recommenda- tions originally adopted by the International Congresses of Zoology and, since 1973, by the International Union of Biological Sciences (IUBS). The ICZN with six principal taxonomic levels of the system are: ¬ Phylum ¬ Class ¬ Order ¬ Family ¬ Genus ¬ Species The major groups of zooplankton in this book are listed as follows: Order Flosculariaceae KINGDOM PROTISTA Family Testudinellidae ¬ SUBKINGDOM PROTOZOA Family Trochosphaeridae ¬ Phylum Sarcomastigophora Family Hexarthridae ¬ Superclass Rhizopoda Family Conochilidae ¬ Class Lobosa ¬ Order Testacealobosa Family Arcellidae Phylum Arthropoda Family Centropyxidae ¬ Subphylum Crustacea Family Difflugiidae ¬ Class Branchiopoda ¬ Order Cladocera Class Filosa Family Bosminidae ¬ Order Testaceafilosa Family Sididae Family Euglyphidae Family Macrothricidae Family Ilyocryptidae KINGDOM ANIMALIA Family Daphniidae ¬ Phylum Rotifera Family Chydoridae ¬ Class Bdelloidea Class Copepoda ¬ Order Bdelloida ¬ Order Calanoida Family Philodinidae Family Centropagidae Family Pseudodiaptomidae Class Monogononta Family Diaptomidae ¬ Order Ploima Family Acartiidae Family Asplanchnidae Family Trichocercidae Order Cyclopoida Family Synchaetidae Family Oithonidae Family Lecanidae Family Cyclopidae Family Lepadellidae