MOLECULAR SYSTEMATICS OF SHRIMP (DECAPODA, BRESILIIDAE) FROM DEEP-SEAHYDROTHERMAL VENTS, I - ENIGMATIC SMALL ORANGE SHRIMP FROM THE MID-ATLANTIC RIDGE ARE JUVENILE RIMICARIS-EXOCULATA

Independent species descriptions of a ''small orange'' caridean shrimp found at deep-sea hydrothermal vents along the Mid-Atlantic Ridge hav e created the synonymous names Iorania concordia Vereshchaka 1996b and Rimicaris aurantiaca Martin et al. 1997. Our genetic analyses involvi ng allozymes and mitochondrial DNA sequences reveal that the ''small o range'' shrimp described in these studies are a juvenile form of Rimic aris exoculata Williams and Rona, a species commonly found at these si tes. In light of this result, we reconsider the life history and ecolo gic characteristics of juvenile and adult stages of Rimicaris exoculat a.