Resumo Os nematoides Acuariidae são normalmente encontrados no trato digestivo de aves aquáticas, incluindo os Procellariiformes. Foram examinadas Calonectris borealis (n=4), Diomedea exulans (n=1), Macronectes giganteus (n=8), Thalassarche chlororhynchos (n=5), Thalassarche melanophrys (n=15), Procellaria aequinoctialis (n=4), Puffinus gravis (n=2) e Puffinus puffinus (n=6), coletados na costa sul do Rio Grande do Sul, Brasil. Dentre os exemplares examinados, 16 (35,5%) estavam parasitados por duas espécies de Acuariidae. Foram identificados Stegophorus diomedeae e Seuratia shipleyi, com prevalência de 26,1% e 21,7%, respectivamente. Existem poucos estudos relacionados a nematoides em Procellariiformes, e aqui registra-se pela primeira vez os Acuariidae Seuratia shipleyi em Calonectris borealis e Procellaria aequinoctialis, e Stegophorus diomedeae em Diomedea exulans, Procellaria aequinoctialis e Thalassarche chlororhynchos.
Abstract Acuariidae nematodes are normally found in the digestive tract of aquatic birds, including Procellariiformes. Were examined Calonectris borealis (n = 4), Diomedea exulans (n = 1), Macronectes giganteus (n = 8), Thalassarche chlororhynchos (n = 5), Thalassarche melanophrys (n = 15), Procellaria aequinoctialis (n = 4), Puffinus gravis (n = 2) and Puffinus puffinus (n = 6), collected on the southern coast of RS, Brazil. A total of 16 birds (35.5%) were parasitized by two species of Acuariidae. Stegophorus diomedeae and Seuratia shipleyi were identified, with prevalences of 26.1% and 21.7%, respectively. Few studies on nematodes in Procellariiformes have been conducted. Here, the acuariids Seuratia shipleyi in Calonectris borealis and Procellaria aequinoctialis and Stegophorus diomedeae in Diomedea exulans, Procellaria aequinoctialis and Thalassarche chlororhynchos were reported for the first time.