Several squat lobster specimens of the genus Munidopsis were collected from an artificially placed carcass fall (cow bones) on Weijia Guyot in the western Pacific Ocean. Based on morphological comparisons and molecular analysis, three specimens were confirmed as juveniles of M. albatrossae Pequegnat & Pequegnat, 1973, which represents the first record of this species in the western Pacific. The other specimens collected are newly described as Munidopsis spinifrons sp. nov., which is distinguished from the closely related species in having a spinose rostrum and basal lateral eyespine on the eyestalk. The M. albatrossae from Weijia Guyot exhibited very low genetic distances when compared with a conspecific sample from Monterey Bay, USA, and the closely related species M. aries (A. Milne Edwards, 1880) from the northeastern Atlantic. A phylogenetic tree based on the mtCOI gene shows M. spinifrons sp. nov. as sister to M. vrijenhoeki Jones & Macpherson, 2007 and M. nitida (A. Milne Edwards, 1880), although M. vrijenhoeki presents a complex relationship with other species in the clade. The systematic status of the new species and the closely related species are discussed.