Streblocerus pygmaeus Sars, 1901

Streblocerus pygmaeus Sars, 1901 View in CoL

Material examined. 5 adult females, UARC 326M.

Remarks. It was one of the most abundant species in the samples. Its body is globular in lateral view, with convolute intestine ( Fig. 1A) and divergent antennules ( Fig. 1B). It can be di erentiated from its congeners by the postabdomen, which bears setae in the preanal marginal portion ( Fig. 1C) instead of spines; these setae form distinct groups ( Fig. 1D), as observed also in populations from Mexico, the U.S.A. and Brazil ( Smirnov, 1992; Gar a-Espejo and Elías-Gutierrez, 2003),although they are not grouped in the population from the Nhamundá River ( Smirnov, 1992). Body length is between 0.21 and 22 mm, average: 0.22 mm (n = 5).

Distribution. It has been recorded in the Neotropical, Nearctic and Oriental regions ( Kotov et al., 2013); nevertheless, the population from China recorded by Chian and Du (1979) is considered to be a doubtful identi cation ( Smirnov, 1992). is is the rst record from the Orinoco region and Colombia.