Two new muricid species (Mollusca Gastropoda) are described from the continental shelf of French Guiana. The first one, Siratus lamyi n. sp., belongs to the subfamily Muricinae and is compared to two close Caribbean and Brazilian species. The second one, Favartia massemini n. sp., belongs to the subfamily Muricopsinae and is compared to six close Caribbean and Brazilian species. For each species, the characters of the spiral sculpture are described using precise structural homologies. Th is study of the shell characters shows that Siratus Jousseaume, 1880, which is often regarded as a subgenus of Chicoreus Montfort, 1810, seems more related to Vokesimurex Petuch, 1994 than to Chicoreus. Then, Siratus is here excluded from Chicoreus and elevated at the genus level.
Mollusca, Gastropoda, Muricidae, Siratus, Favartia, French Guiana, new species