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Abstract

Two new species of so-called aquatic Oligochaeta are described from soil and litter samples originating
from terra firme sites of the Amazonian primary rain forest. Bothrioneurum righii n.sp. (Tubificidae) is
characterized by posterior dorsal chaetae with very large distal teeth and much reduced proximal teeth.
The new genus Pedonais (Naididae) resembles Allonais but differs from it in the absence of hair chaetae,
in the similarity of dorsal and ventral chaetae, and in the presence of well-developed pharyngeal glands.
Pedonais crassifcaucis n.sp. reproduces asexually by fragmentation and subsequent regeneration, and the
same is assumed for B. righii. Sexually mature specimens were not found. Both species exhibit traits that
can be conceived as adaptations of aquatic oligochaetes for a successful colonization of terrestrial habitats.