BUTICULOTREMA-STENAUCHENUS N-GEN, N-SP (DIGENEA, OPECOELIDAE) FROM MALACOCEPHALUS-OCCIDENTALIS AND NEZUMIA-AEQUALIS (MACROURIDAE) FROM THE GULF-OF-MEXICO

Buticulotrema stenauchenus n. gen., n. sp. (Opecoelidae: Opecoelinae) is described from the macrourid fishes Malacocephalus occidentalis Goo de and Bean, 1885, and Nezumia aequalis Gunther, 1878, collected in Ju ne 1971 from the DeSoto Canyon area of the Gulf of Mexico at a depth o f 495 nl. Eight of 25 (32%) M. occidentalis and 1 of 8 (13%) N. aequal is examined were infected with the new opecoelid. Specimens of Bathyga dus macrops Goode and Bean, 1886, and Coelorhynchus coelorhynchus Riss o, 1810, collected at the same time were not infected with B. stenauch enus. The new genus most closely resembles Genitocotyle Park, 1937, bu t differs in that it lacks an accessory sucker behind the genital pore , contains a blind rather than canalicular seminal receptacle, and has a slightly pedunculate acetabulum, a pharynx that is longer than wide , and a distinctive, long-necked, bottle-shaped body. Buticulotrema st enauchenus is also similar to Pseudopecoelus von Wicklen, 1946, but th e latter lacks a blind seminal receptacle.