Forsskål (1775) was the first binominal author to describe the fishes of this genus. He described four species (nebulosus, mahsena, harak and ramak) from the Red Sea as members of the genus Sciaena. Although his descriptions were too incomplete to char-acterize those species definitely, his type specimens are kept in the Zoologisk Museum, K.øbenhavn. Smith (1959) and Klausewitz & Nielsen (1965) examined and photo-graphed the types which are dried skins of the half side of fishes with some bones attached.

After Bloch & Schneider (1801) and Lacepède (1802) added two and one more spe-cies respectively, Valenciennes enlarged this genus to an assemblage of 44 species in 1830 in the exhaustive work "Histoire Naturelle des Poissons" by Cuvier & Valen-ciennes. He reviewed this genus by studying many specimens from various parts of the world. Though a majority of his material was from the Museum National d'His-toire Naturelle in Paris, some of his species are based on specimens from some other museums in Europe. Some other species of his are based on drawings by earlier natu-ralists. In the library of the Museum in Paris there is a notebook written by Valencien-nes with color sketches, which was used as the basis of his published descriptions. Those color sketches are a useful supplement to those descriptions, most of which are not accompanied by figures. Valenciennes observed not only the external appearance of the fishes but also such anatomical features as the alimentary canal and the gas blad-der. In spite of all his efforts, he could not obtain exact enough knowledge of those fishes. As a result, more than half of his species are junior synonyms of other species. The genus Lethrinus had been established a year before by Cuvier (1829). He had pointed out for the first time the very clear diagnosis that the fishes of this genus do not have any scales on their cheek.

Bleeker also studied this genus extensively, and introduced 10 species between 1851 and 1873. Most of his material was collected from the East Indies, He gave colored illustrations of 15 species in his "Atlas " (Bleeker, 1873-76; 1876-77). Those illustra-tions show their characteristic body shapes and color patterns much better than any precise written descriptions.

Klunzinger (1870-71; 1884) made a review of the species from the Red Sea with some colored illustrations. He studied these fishes in detail and described 9 species with an excellent key.

Fowler (1933) recognized 30 species as valid in his "Fishes of the Philippine and Adjacent Seas." He not only exhaustively compiled the literature in the form of large synonym lists, but also examined more than a thousand specimens he had collected. However, he could not examine the species well enough to provide a guide for iden-tification, and his work is most useful as a reference book to the literature.

In addition to the above works, many authors made faunal studies of various regions of the world. Noteworthy among them are Day (1875-89, India), Sauvage (1875-91, Madagascar), Herre & Montalban (1927, Philippines), McCulloch (1929-30, Australia, without descriptions), Weber & Beaufort (1936, Indo-Australian Archipel.), Schultz et al. (1953, Marshall and Mariana Is.), Smith (1959, western Indian Ocean), Wheeler (1961, western Indian Ocean), Munro (1967, New Guinea) and Sato (1971, Japan).

As for the systematic position, this genus has been placed almost capriciously in the family Sparidae (Günther, 1859; etc.) or Lutjanidae (Weber & Beaufort, 1936; Schultz et al., 1953; etc.), and sometimes in an independent family Lethrinidae (Fowler, 1933; etc.). Norman (1957) combined Lethrinus with Monotaxis, Gnathodentex and Gymno-cranius for the first time under the same family Lethrinidae and also included Penta-podus in this family. Akazaki (1958; 1962) supported Norman's grouping through his comparative studies of internal morphology, though he excluded Pentapodus from Norman's Lethrinidae. He also reported that his Lethrinidae is closely related to Sparidae and Nemipteridae rather than to Lutjanidae, which bear a superficial resem-blance to the Lethrinidae.