Synalpheus biunguiculatus (Stimpson, 1860)

Material examined. For this species, samples from Zacatoso (17°39´N, 101°37´W), in the Ixtapa region were numerous, with six males (ICMyL MAZ 9062A), five females (ICMyL MAZ 9062B), 12 juveniles (ICMyL MAZ 9062C), and four ovigerous females (ICMyL MAZ 9062D).

Remarks. It is a common species on corals and is widespread in the Gulf of California (Wicksten 1983) in Bahía Santiago and in the Huatulco region (Hermoso 1999). In our study, the species was surveyed in several sites from the Islas Marietas to the Huatulco region, associated with corals.