Redescription of Cosmocephalus obvelatus (Creplin, 1825) (Nematoda: Acuarioidea) from Larus delawarensis Ord (Laridae)

Abstract

Cosmocephalus obvelatus (Creplin, 1825) Seurat, 1919 is redescribed on the basis of specimens from the oesophagus of Larus delawarensis Ord from Lake Ontario. The specimens were compared with Creplin's (1825) types of C. obvelatus and the following synonyms of obvelatus are recognized: Cosmocephalus diesingi Molin, 1858; Spiroptera adunca Stossich, 1892 (not Creplin, 1846); Cosmocephalus aduncus Yorke and Maplestone, 1926 (not Creplin, 1846); Cosmocephalus faridi Khalil, 1931; Cosmocephalus firlottei Rao, 1951; Cosmocephalus tanakai Rodrigues and Vicente, 1963. Creplin's types of Cosmocephalus adunca (Creplin, 1846) Yorke and Maplestone, 1926 were examined and shown to belong to the genus Paracuaria resulting in the new combination Paracuaria adunca (Creplin, 1846) n.comb. Cosmocephalus asturis Yorke and Maplestone, 1926 is transferred to the genus Synhimantus, i.e. S. asturis (Yorke and Maplestone, 1926) n.comb. Besides C. obvelatus, the genus Cosmocephalus apparently contains only C. capellae Yamaguti, 1935; C. imperialis Morishita, 1930; and C. jaenschi Johnston and Mawson, 1941.