Abstract:Testate amoebae are common single-celled eukaryotic organisms in aquatic ecosystems. Despite their important role in these ecosystems, and their potential as bioindicators and paleoindicators, they remain poorly studied in Mexico. The major objectives of this study were to: 1) increase knowledge of testate amoebae in Mexico's tropical lakes, and 2) create a catalog of high-quality scanning electron micrographs that can be used for future ecological and paleoenvironmental studies. We collected surface-sediment samples from 29 lakes, located in the Transmexican Volcanic Belt, one at each lake during June and October 2011, and March 2013. Sediments were collected with an Ekman grab and preserved in anhydrous ethanol. Sub-samples were observed under a stereomicroscope and morphometric data for each species were recorded. Total diameter and aperture diameter were measured on circular tests. Irregularly shaped tests were measured for length and width of the aperture and for the size of the whole test. If a specimen possessed spines, the length of one randomly selected spine was measured. The best-preserved specimen of each taxon was photographed with an optical microscope and a scanning electron microscope (SEM). We found 41 taxa of testate amoebae belonging to the genera: Arcella, Argynnia, Centropyxis, Cucurbitella, Cyclopyxis, Cyphoderia, Difflugia, Euglypha, Lesquereusia, Pentagonia, Pseudodifflugia and Scutiglypha. Twelve species not previously reported for Mexico were recorded, along with 13 varieties. The average number of taxa recorded in each lake was eight, and the highest taxonomic richness was 18. The taxon found in the greatest number of lakes was Centropyxis aculeata var. aculeata. Taxonomic richness varied among lakes in the same region. This could reflect lake-specific differences in environmental conditions, underscoring the need for more detailed studies that include collection of data on physical and chemical variables in the lakes. Our results highlighted the need of further studies for the distribution patterns and ecology of lacustrine testate amoebae. Rev. Biol. Trop. 64 (1): 377-397. Epub 2016 March 01.

de 142 publicaciones del período de 1841-2012. En el recuento se registraron 315 especies diferentes de amibas. Los grupos dominantes fueron Amebozoa, Rhizaria y Excavata, con una importante contribución de las amibas testadas y de los gimnamebidos del tipo acantamebidos. La mayoría de los trabajos se han realizado en los estados del centro de la República Mexicana, especialmente en el Distrito Federal, correspondiendo con la ubicación de los principales grupos de investigación. Nueve estados no tienen ningún estudio de amibas de vida libre incluyendo algunas de las regiones más biodiversas de México como Chiapas, Tabasco y Yucatán. El primer registro de amibas en nuestro país fue en 1841. El mayor número de registros se presenta a partir de los años sesenta del siglo pasado y ha mantenido una tendencia de constante crecimiento, la perspectiva es que existen todavía elevados números de especies amibianas por descubrir, muchas de ellas fundamentales para el funcionamiento de gran número de ecosistemas. Esta es la primera revisión del estatus en que se encuentran las investigaciones en México enfocada exclusivamente al grupo de las amibas de vida libre.Palabras clave: Protozoa, gimnamebas, amibas de vida libre, anfizóicas, amibas testadas.