OMANA, E.C.; SHUSTER, S.M.; Northern Arizona University; Northern Arizona University: Paradella dianae in Mexico: �Alternative male morphs? �Si! �Hermaphrodites? �No!

Protandrous sex change is the most common pattern of sequential hermaphroditism in the Crustacea. Recently, three species of sphaeromatid isopods have been found to exhibit protogynous sex change: Gnorimosphaeroma oregonense, G. naktongense, and Paradella dianae, an invasive species with now cosmopolitan distribution. Laboratory studies of the former two revealed that females developed into functional males after releasing their broods. Hermaphroditic individuals of the latter species were described from collections in the Indian River Lagoon, FL. Alternative male morphs have never been described in any of these protogynous species. We made extensive field collections of Paradella dianae from the northern Gulf of California. We found no evidence of hermaphroditism in this population after females released their broods. In laboratory rearing experiments we found no evidence of sex change. Rather than developing from females, there are three male “morphotypes” in the northern Gulf population. Here we distinguish each of the three stages and discuss the sexual competency associated with each.