Abstract
A gonodactylid stomatopod, Gonodactylaceus falcatus ($Forsk{\aa}l$, 1775), collected from Jeju Island is reported for the first time in the Korean fauna. The genus Gonodactylaceus, which is also new to Korea, differs from other genera by the presence of a subglobular cornea, five longitudinal dorsal carinae on the telson, and the absence of a movable proximal spine on the propodus of the raptorial claw. Within genus Gonodactylaceus, G. falcatus can be easily distinguished from other congeners by the presence of a bilobed knob on the telson, a rounded anterolateral margin of rostral plate, and a lobe between terminal spines of uropodal protopod. In this paper, detailed descriptions and illustrations of G. falcatus are provided. As a result of this study, seven species of stomatopods including this species are now recorded in the Korean fauna. A key to the species of Korean mantis shrimp is also presented.