A common inhabitant of deep sandy bottoms in the Rosario area. Feed on crustaceans, polychaetes, limpets, and carcasses. One important predator is the giant octopus Octopus dofleini
and the yelloweye rockfish Sebastes ruberrimus.
One interesting feature about this species is that it has a different number of multiarticulations on the carpus of its two second pereopods: The left pereopod has 27-31 articles and is longer, while the shorter right second pereopod has only 8 or 9 articles on the carpus. Breeding ends in late October. Females carry their eggs on the abdomen for 4-5 months, remain in deep water. Eggs hatch in March or April. Larvae settle from the plankton in May and June. Juveniles feed in shallow water during summer, especially among Agarum fimbriatum
and A. clathratum
kelp. They seem to avoid Laminaria saccharina
. During their second fall (carapace length 2.8 cm) they become males, which they remain until they grow to 3.3 cm carapace length, at which time they become females. Females may mate only once. May not live longer than 4 years.