Molecular systematics of shrimp (Decapoda: Bresiliidae) from deep-sea hydrothermal 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 have created the synonymous names Iorania concordia Vereshchaka 1996b and Rimicaris aurantiaca Martin et al. 1997. Our genetic analyses involving allozymes and mitochondrial DNA sequences reveal that the "small orange" shrimp described in these studies are a juvenile form of Rimicaris exoculata Williams and Rona, a species commonly found at these sites. In light of this result, we reconsider the life history and ecologic characteristics of juvenile and adult stages of Rimicaris exoculata.