Carapace, chelipeds and ambulatory legs covered with rather scaly spinules. A transverse gastro-cardiac furrow very deep and shining; dorsal surface behind it thickly covered with spinules, each of which is curved forward and arising from a broad base made by some granules; a median gastric tubercle surprisingly larger, compressed so as to be a plate, directing obliquely forward; a pair of protogastric tubercles directing obliquely forward and outward; a median cardiac tubercle just behind gastro-cardiac furrow nearly equal to protogastric tubercle. Anterolateral angle produced to be a depressed long tubercle, being followed by a smaller tubercle just behind it. Rostral spine simple withoutt any accessory spines and directed obliquely upward just at median part so a as to be parallel to gastric tubercles. Second to fourth abdominal segments each with a transverse smooth furrow and a median spine.
Distribution:
Previously known from off Cuba and Dominica, 600-990 m deep.
Remarks:
This species is close to the cosmopolitan congener, M. rostrata (A. Milne Edwards), but separated from it by having the rostrum laterally unarmed.