A new record is provided for the rarely collected hexapodid crab Paeduma cylindraceum (Bell, 1859), extending its distributional range to the southeastern Gulf of California, Mexico. The specimen, a large mature male of 13.7 mm carapace width, is the third ever collected since the male holotype was described. The male first gonopods are illustrated for the first time. The appendage shows unique features for the family, including a row of strong, marginal conical spine on the distal section of the shaft, and a crown of concentric series of strong, conical spines near tip.