Published online by Cambridge University Press: 14 July 2015
Analysis of previously unstudied shell characters reveals the existence of three new genera of Cenozoic muricid neogastropods. These are the new genera Muregina (type species: Murex lugubris Broderip, 1833; ?early Miocene, Pliocene to Recent, eastern tropical Pacific); Kestocenebra (type species: Murex curvicosta Grateloup, 1840; early to late Miocene, Europe); and Edithais (type species: Concholepas drezi Vokes, 1972; early to late Miocene, circumtropical).
A review of muricids with a labral tooth (a ventrally directed projection on the outer lip) shows that this structure forms in several distinct ways. It may form at the end of an external groove (as in Muregina) or cord (as in Kestocenebra), grow continuously or discontinuously, and lie at positions ranging from the upper end of the siphonal canal to just below the middle of the outer lip. The labral tooth evidently evolved independently several times, often quite recently in genera such as Muregina, in which older representatives lack a labral tooth.