The apogonid fish genus Pseudamia is characterized as follows: dorsal rays VI-I, 8-10; anal rays II, 7-10; pectoral rays 15-17; deciduous cycloid scales; 2 inconspicuous lateral lines; a large mouth with villiform and slender canine teeth; villiform teeth on vomer, palatines, and ectopterygoids; no downward-directed spine at the lower posterior corner of maxilla; a partially serrate preopercular margin; an elongate body (the depth 3.65-4.7 in SL); and a large rounded caudal fin.
This genus consists of 5 species: P. amblyuroptera (Bleeker) [P. polystigma (Bleeker) is a synonym], from the Indo-Malayan region; P. gelatinosa Smith, wide-ranging from the coast of East Africa to French Polynesia; P. hayashii n. sp., from the Gulf of Aden and Rowley Shoals off Western Australia through the western Pacific to the Samoa Islands; P. tarri, n. sp., described from a single specimen from the Persian Gulf; and the dark-barred P. zonata, n. sp., which ranges from New Guinea to the Ryukyu Islands.
Pseudamia amblyuroptera and P. gelatinosa have 39-43 scales in longitudinal series on the body; they differ from one another in counts of anal soft rays (amblyuroptera with 9 and gelatinosa with 8) and of developed gill rakers (amblyuroptera with 2 + 9 and gelatinosa with 1 + 7). Pseudamia tarri has 31 scales in longitudinal series and a relatively deep body (depth 3.75 in SL). Pseudamia hayashii and P. zonata have 23-25 scales; they are readily differentiated by counts of dorsal and anal soft rays (8 for both fins of hayashii and 9 or 10 dorsal rays and 9 anal rays for zonata) and developed gill rakers (1 + 7 for hayashii and 6 + 16-18 for zonata). Also, P. zonata is distinctive in having a flat interorbital space and villiform teeth externally on the side of the jaws.