Freshwater ecology in the Mato Grosso, Central Brazil, IV: Associations of testate Rhizopoda

Abstract

Summary Samples from five meander lakes in the valley of the Rio Suia Missu and from the Rio das Mortes at Xavantina, contained a total of 43 species of testate rhizopods, including a new genus with a complex multiporate mouth. Only one of the species is restricted to S. America in its known distribution. Analysis of the associations in the samples revealed that they were inadequate for inter-lake comparisons, and that the samples were representative of more restricted habitats. A comparison of the total list of species with the known fauna of the River Sokoto in Nigeria gave a higher index of similarity than any of the inter-lake comparisons in the Suia Missu. This is taken as an indication of the existence of an association that might be widespread in tropical riverine meander-lake systems.