Morphology and DNA Data Reveal a New Shrimp Species of Genus Stimpson, 1860 (Decapoda: Hippolytidae) from the Western Atlantic.

The genus Stimpson, 1860 comprises 17 described species of marine shrimps, most of them distributed in the Indo-West Pacific and eastern Pacific. Only three species are recorded in the Atlantic. When comparing specimens of (Stimpson, 1871) from both sides of the Atlantic by means of a combination of morphological and molecular data, we recognized a new species of from Brazil (Rio Grande do Norte, Bahia, Rio de Janeiro and São Paulo). The phylogenetic tree generated on the basis of the 16S gene showed a clear separation of the specimens of the new species from the other closely related species analyzed. The analyses also evidenced that the new species and are sister taxa. Although very similar, both species can be easily separated by features of the scaphocerite and eyestalk. Rostrum form and dentition, characters usually used for recognition, were highly variable in both species. Thus, herein the new species is described, illustrated, and compared with morphological similar species of . A key for the Atlantic species is also provided.