Hydrobiologia 360: 63–73, 1997. 63 A. Brancelj, L. De Meester & P. Spaak (eds), Cladocera: The Biology of Model Organisms. c 1997 Kluwer Academic Publishers. Printed in Belgium. A checklist of the littoral cladocerans from Mexico, with descriptions of five taxa recently recorded from the Neovolcanic Province Manuel El´ ıas-Guti´ errez, Jorge Ciros-P´ erez , Martha Guti´ errez-Aguirre & Adri´ an Cervantes-Mart´ ınez Laboratorio de Zoolog´ ıa. UNAM Campus Iztacala AP 314, CP 54000. Los Reyes Iztacala, Tlalnepantla, Edo. de M´ exico, Mexico Department de Microbiologia: Ecologia (Edifici D’Investigacioni) Universitat de Valencia, E-46100 Burjassot (Valencia), Spain Abstract By 1996 an inventory of Mexican cladocerans had recorded 48 species of which 22 belonged to Chydoridae, Macrothricidae and Ilyocryptidae. Unfortunately, most of the surveys were made before researchers knew that these crustaceans are not entirely cosmopolitan. For this reason and the lack of deposited type material, many of these records are doubtful and need detailed analyses. In this study, material from 18 water bodies located in the Neovolcanic Province of Mexico is analyzed and compared with the literature. Also, males of Camptocercus dadayi Stingelin and Leydigia leydigi (Schoedler) and new records Eurycercus longirostris Hann and Biapertura intermedia (Sars) are described. Half of the total number of species recorded are American endemics and represents a mixture of the North and South American fauna, suggesting that Mexico constitutes a transition between Nearctic and Neotropical zones. Introduction The cladocerans of Mexico are little known, and no single work has been devoted to the study of the lit- toral fauna belonging to the Anomopoda. A summary of most cladoceran papers published from different regions is given in Table 1. Most of the surveys have been done in the pelagic zones of lakes and reservoirs where Macrothricids, Ilyocryptids and Chydorids are caught only occasionally. By 1996, the inventory of these families recorded only 22 species. So the pur- pose of this review is to establish the current state of knowledge of these animals in Mexico. Study area Surveys were conducted in 18 water bodies including artificial reservoirs, puddles and natural lakes, located in the North (Panuco River Basin) and Central (Ler- ma River Basin) regions of the State of Mexico. All sampling sites are located between 98 37 –100 38 W and 18 22 –20 17 N, at more than 2000 m above sea level (Figure 1). Material and methods Samples from each water body were collected by mov- ing a conical net (50 m mesh size with a metal handle of 1.5 m long), through growths of macrophytes and over the substrates of the littoral zones. All samples were preserved with 4% sugar-formalin. Sampling was carried out intermittently during the period 1993–1995. The animals were analyzed and dissected under a stere- omicroscope and identified using a compound micro- scope. Standard literature (e.g. Smirnov, 1971, 1992) and comparison with original descriptions were used. Drawings were made with a camera lucida attached to a Nikon Labophot II compound microscope. The material was deposited in the Reference Collection at Laboratorio de Zoolog´ ıa Campus Iztacala (Universi- dad Nacional Aut´ onoma de M´ exico).