First records from Pacific Mexico of the rare deep-water mysid Ceratomysis spinosa (Crustacea, Peracarida, Mysida, Petalophthalmidae)

The deep-water mysid Ceratomysis spinosa Faxon, 1893, previously known from Panama, Japan, the Sea of Okhotsk, the Bering Sea and Alaska, USA is reported for the first time off the western coast of Mexico, in the eastern Pacific. The specimens, a male of 27.5 mm in total length (TL) and five females of 28.5–34.5 mm TL, were collected between depths of 1296 and 1580 m. The telson is illustrated, showing numerous setae on the lateral margins, and longer, robust setae in the distal third and on the posterior margin.