Record of Thermocyclops tenuis (Marsh, 1910) (Copepoda: Crustacea) in the Pantanal (Mato Grosso do Sul - Brazil).

The aim of this note is to record the occurrence of the copepod Cyclopoida Thermocyclops tenuis in the Pantanal region, Central West of Brazil. The sampling was carried out in September, 2008, in a small artificial pond with an area of 22 m and 0.5 m deep, located in the city of Corumbá, MS, at 19° 00” 02’ S and 57° 37” 50’ W. The material was concentrated in a plankton net with 68 μm mesh size and fixed in a 4% formaldehyde solution. The organisms were identified in an optical microscope with image capture and drawings accomplished with Turbo Cad 6.5 software. Thermocyclops tenuis was found in the sample making up the main population of Cyclopoida (97%) together with Mesocyclops longisetus (Thiébaud, 1914). 1. Characteristics of the species