CARAPIDAE Onuxodon parvibranchium, 8.3 cm (photo by Ukkrit Satapoomin) Onuxodon parvibranchium (Fowler, 1927) Oyster Pearlfish P1 14-16; P2 0. Body elongate, its depth about 6-8 in total length; trunk strongly compressed. Eyes small, its diameter 6.3-12.5 in head length. Upper and lower jaws with large symphyseal fangs, lacking villiform teeth. No sensory papillae on head or anterior lateral line. Dorsal fin origin posterior to anal fin origin. Pectoral fin short, its length 16.7-33.3 in head length. Anus behind pectoral-fin base. Posterior part of swimbladder, without ridges, not embedded in hypaxial musculature. Color: body translucent with black vertebrae. Caudal fin and posterior parts of dorsal and anal fins blackish. Size: maximum length 10 cm. Distribution: widely distributed in the Indo- Pacific, from South Africa east to the Line Islands, and southern Japan south to Australia. Remarks: large oysters and clams reported as hosts.