p. 69-241 : ill., maps ; 27 cm.Includes bibliographical references (p. 228-241)."The American species of groupers constitute a block of serranid fishes which have been studied as a unit. Field investigation of their biology and life colors has supplemented laboratory studies on morphology, variation, and geographic distribution as indicated by existing museum specimens and literature records. Keys to the genera and species are given and previous literature is summarized in a synonymy for each species. 2. The groupers are moderate-sized to large-sized serranid fishes of warm seas. Most are solitary, reef-dwelling carnivores. In some areas they are the object of intensive, but local, commercial fisheries. Spawning takes place in the winter to late spring, depending on the latitude, but the manner of spawning is not known. The eggs are small, buoyant, and numerous. All of the species so far studied are protogynous. There is a pelagic larval stage during which the groupers can traverse great distances, but the adults are rather sedentary and probably rarely stray far from coral or rock reefs. 3. Groupers undergo considerable color variation of three types: 'instantaneous,' under nervous control; bathymetric, correlated with the environment, some species having strikingly different deep-water and shallow-water color phases; and xanthic, a yellow color phase under genetic control that characterizes small parts of the populations in a few species. A juvenile color phase different from that of the adult is present in some, but not all, species. 4. Osteological characters are useful in grouper classification and the osteology of Epinephelus guttatus is described in detail as a basis of comparison. 5. Subfamily names are not used in this report because present knowledge does not permit compartmentalization at that level. 6. The genus Paranthias is considered monotypic, with allopatric western Atlantic and eastern Pacific populations. 7. Twenty-one American species of Epinephelus are recognized. Seven distinct lines seem to be present. The nominal genera Cephalopholis, Petrometopon, Alphestes, Dermatolepis, Promicrops and Garrupa are placed in the synonymy of Epinephelus. Epinephelus niphobles is a synonym of E. niveatus, which thus has Atlantic and Pacific populations. Other species that occur on both sides of the Isthmus of Panama are Epinephelus nigritus, itajara, and probably mystacinus although the only Pacific record seems to be a small specimen from the Galápagos and this could be a locality error. 8. Two American species of the subgenus Dermatolepis are well differentiated, one on each side of the Central American Isthmus. 9. The eastern Pacific species previously known as Cephalopholis acanthistia is clearly a member of the E. niveatus species-group. 10. The transverse skull crests of Petrometopon are not sufficient grounds for recognizing it at either the generic or subgeneric levels. It is combined with Cephalopholis as a subgenus of Epinephelus. 11. Epinephelus afer occurs in the Pacific Ocean as well as in the Atlantic; E. multiguttatus is confined to the eastern Pacific. Apparently the subgenus Alphestes has twice invaded the eastern Pacific from the western Atlantic. 12. Thirteen species of Mycteroperca are recognized. These fall into two species-groups. 13. Some proportional measurements are relatively constant among most species of groupers. Others provide good generic and species-group characters and a few furnish useful species characters. Tables of measurements are given for each species except Mycteroperca prionura and M. cidi. 14. Barriers to dispersal and methods of transport of groupers are discussed. Three centers of distribution seem apparent: the eastern Pacific, the Gulf of Mexico, and the West Indies. There is a sharp faunal break across the Straits of Florida and the Gulf Stream seems to be an effective, although incomplete, barrier. There appear to be several levels of differentiation between species in these regions. These may be due in part to different rates of evolution, but are more probably a reflection of different periods of isolation. The last closure of the Middle America gap was late Pliocene and four species remain unchanged since that time. 15. A phylogeny of the American groupers is proposed that is based on the information available at this time"--P. 226-227
