Deontostoma coptochilus, a new species of marine nematode (Leptosomatidae), is described. The specimens upon which the description
is based were extracted from sediment within the foot cavity of the deepsea anemone Actinauge longicornis (Verrill, 1882) collected at 1,000 m
depth off the coast of Uruguay. This is a new depth record for a species
of this genus. The associations between various species of Deontostoma
and other marine organisms is discussed.