The nematode Pelecitus fulicaeatrae (Diesing, 1861) (Onchocercidae, Dirofilariinae) was found in the leg of a silvery grebe Podiceps occipitalis (Garnot, 1826) (Aves, Podicipediformes) at Puerto Madryn, Argentina. The specimens redescribed in this note are based on 7 females and 3 males. This is the first Argentinean record for this species and the second for South America, and represents the southern-most record of a species from this genus.
Decorataria decorata (Cram, 1927) is redescribed on the basis of light-microscopy and SEM observations on specimens collected from the stomach of Podiceps cristatus and P. grisegena from Bulgaria. The SEM study revealed the presence of a porebearing field on each pseudolabium and a pair of spines (one dorsal and one ventral) situated between bases of the cordons. The deirids are spine-like and minute. The light-microscopy examination showed the presence of ornamentation situated under the dorsal surface of caudal alae. The occurrence of D. decorata in Bulgaria is a new geographical record.