Abstract Lysmata rafa n. sp. is described from freshly collected specimens from the Keys West Lakes, Florida Keys, and from a museum specimen collected at Bear Cut, Biscayne Bay, Florida. The new species is morphologically most similar to the western Atlantic Lysmata rathbunae Chace, 1970 and the eastern Pacific Lysmata gracilirostris Wicksten, 2000, but can be distinguished from them by the number of carpal segments in the second pereiopod; the length and dentition of the rostrum; the shape and number of spines on the dactylus of the third to fifth pereiopods; and the absence of a tooth on the pterygostomial margin of the carapace. Despite being a shallow-water species, L. rafa n. sp. has extremely elongate walking legs and third maxilliped that are more typical to deep-water or cave dwelling carideans. [ABSTRACT FROM AUTHOR]