Descriptions of Otukaia crustulum new species (Gastropoda: Trochoidea: Calliostomatidae) and Margarites huloti new species (Gastropoda: Trochoidea: Trochidae) from a methane seep area off Chile

Two new species of Trochoidea are described from a methane seep area off central Chile ( similar to 36 degree S). Otukaia crustulum new species is compared with similar calliostomatid species such as Otukaia kiheiziebisu (Otuka, 1939), O. eltanini Dell, 1990, and Calliostoma jacquelinae McLean, 1970. The new species is separated from these similar species by convex whorls bearing a prominent abapical cord and an almost invisible adapical cord, and five spiral cords on the base. Margarites huloti new species from the same locality is compared with similar mar-garitine species, such as M. shinkai Okutani, Tsuchida and Fujikura, 1992, M. salmonea (Carpenter, 1864), and Solariella tavemia Dall, 1919, and with calliostomatid species such as Calliostoma nudiusculum (von Martens, 1881), C. magaldii Caldini and Guimaraes-Prado, 1998 and C. keenae McLean, 1970. The new species differs mainly by the size of its shell, elevated spire, rather thick spiral cords on the whorls, numerous low spiral cords on the base and the narrow, funnel-shaped, umbilicus.