The deep-sea nematodes are known to be very rich in species numbers and most of the species still remain to be described (Fonseca et al., 2006). The true extent of their species diversity is still unknown. In a recent review of the published literature on nematodes, 638 valid species belonging to 175 genera and 44 families are described from the deep sea (Miljutin et al., 2010). The major impediment in describing new species
from the deep sea is the small size, difficulty to get enough specimens of the same species for descriptions and the low proportion of males present in samples. Even though several hundred unknown species can be found in a sample of 1000 nematodes, most of them may be represented by only a few or even one specimen (Miljutin et al., 2010). Members of the family Desmodoridae have been documented in most of