Abstract
Sigambra grubii Müller, 1858 has been reported from many different coastal environments in Brazil and the Grand Caribbean. However, more than one species was thought to be included under this species group name. After the study of several subtle and consistent differences in specimens fitting the description S. grubii, a new Grand Caribbean species is herein recognized and described as S. hernandezi sp. nov. Further, the study of other Sigambra specimens prompted the examination of type specimens of S. bassi (Hartman, 1947), and of S. wassi Pettibone, 1966 to clarify some morphological features, and three other new species are recognized and newly described: S. diazi sp. nov. and S. ligneroi sp. nov. from the southeastern Caribbean (Venezuela), and S. olivai sp. nov. from the northwestern Caribbean (México). Morphological features are also clarified for S. grubii by comparison with specimens from the type locality, Florianópolis, Brazil, and with type specimens of S. bassi from Florida (U.S.A.), and non-type specimens of S. wassi from Virginia (USA). A key to identify all species of Sigambra is also included.