Echinobreviceca coelorhynchae n. gen., n. sp. (Echinobrevicecinae n. subf.), a fellodistomid from Coelorhynchus coelorhynchus (Macrouridae) from the Gulf of Mexico.

During a study of digenean parasites of deep sea fishes from the Gulf of Mexico, 38% (5 of 13) of Coelorhynchus coelorhynchus Risso, 1810, (Macrouridae) were infected with a total of 33 specimens (6.6/infected fish) of an undescribed species of Fellodistomidae representing a new genus and subfamily. Other macrourids collected at the same time (Bathygadus macrops Goode and Bean, 1886, Malacocephalus occidentalis Goode and Bean, 1885, and Nezumia aequalis Günther, 1878) were not infected with Echinobreviceca coelorhynchae n. gen., n. sp. The new species is most similar to members of the subfamily Baccigerinae, but differs in having an I-shaped excretory vesicle, a densely spined tegument, a pretesticular ovary, and a blind seminal receptacle. Echinobrevicecinae n. subf. is separated from other subfamilies in the family by having an I-shaped excretory vesicle. Echinobreviceca n. gen. is established as the type and only genus in the new subfamily, and E. coelorhynchae n. sp. as the only known species in the genus.