Neobirsteiniamysis inermis (Willemoes-Suhm, 1874) (Peracarida, Mysida, Mysidae) in western Mexico

Abstract The offshore mysid Neobirsteiniamysis inermis (Willemoes-Suhm, 1874) is reported for the first time in western Mexico. A large series of specimens (168 specimens: 44 males, 124 females) was obtained from samples taken with a large benthic sled in as many as 28 localities distributed off the west coast of the Baja California Peninsula (15), in the Gulf of California (11), and off SW Mexico (2). Only one ovigerous female was collected. A complete description of the material, based on a mature specimen, is provided, including SEM images of the mandibles, which are described in detail, and of the eyes.