Parasunaristes chelicerata was found in about half of the domiciles constructed by the corophioid amphipod Siphonoecetes sp. in the northern Red Sea in shallow water. Domiciles are composed of a secreted tube with embedded sediment particles extending into the opening of a gastropod shell (86%), a polychete tube (10%), or another object. The male harpacticoid antenna 1 is strongly subchelate, with the slender apical (4th) segment closing against the massive 3rd segment. Right and left subchelae may be symmetrical, or one may be much larger than the opposite subchela. Of 27 males examined, in 19 right and left subchelae were equal (70%), in 6 (22%) the right subchela was larger, and in 2 (7.4%) the left subchela was larger. In maxilla 2 the claw of the basis is much larger and more strongly curved in the female.