A new species of lysmatid shrimp, Lysmata leptodactylus n. sp., is described and illustrated based on specimens collected from the subtidal zone in Guangdong province, South China Sea. The new species bears distinctly unequal second pereiopods and uniquely elongated gracile dactyli of the ambulatory pereiopods. These characters, combined with the rostral formula, and stylocerite proportion, immediately distinguish Lysmata leptodactylus n. sp. from all known species of lysmatid shrimp.