The subfamily Cyclasteropinae is revised using the Hennigian system for deriving the cladistics of suprageneric catagories(sic). The Cylindroleberididae is subdivided into 3 subfamilies: Cylindroleberidinae Müller, 1906; Cyclasteropinae Poulsen, 1965, and Asteropteroninae, new subfamily, of which the last 2 are treated herein. The Cyclasteropinae is divided into 3 tribes: Cycloleberidini Hartmann 1974, Cyclasteropini Poulsen, 1965, and Tetraleberidini, new tribe. The Cyclasteropini contains only 1 genus,
Cyclasterope Brady, 1897. The Cycloleberidini contains 3 genera
Cycloleberis Skogsberg, 1920;
Leuroleberis, new genus, and
Alphaleberis, new genus. The Tetraleberidini contains 2 genera:
Tetraleberis, new genus, and
Amboleberis, new genus. The Asteropteroninae contains 7 genera:
Actinoseta Kornicker, 1958;
Asteropella Poulsen, 1965;
Asteropteron Skogsberg, 1920;
Microasteropteron Poulsen, 1965;
Asteropterygion, new genus;
Pteromeniscus, new genus, and
Omegasterope, new genus. The following new species are described and illustrated:
Leuroleberis sharpei,
L. mackenziei,
Alphaleberis alphathrix,
Tetraleberis maddocksae,
T. tanzania,
Tetraleberis species 1,
Amboleberis antyx,
Actinoseta hummelincki,
A. jonesi,
A. nodosa,
Asteropella trithrix,
A. slatteryi,
A. kaufmani,
A. maclaughlinae,
Asteropella species 1,
Asteropterygion thomassini,
A. romei,
A. dayi,
A. peterseni,
Pteromeniscus intesi, and
Microasteropteron bacescui. In addition, many old species
are redescribed and illustrated. At least 1 species in each genus is illustrated. Keys are presented for the identification of early growth stages as well as for the identification of subfamilies, tribes, genera, and species. With few exceptions members of the Cyclasteropinae and Asteropteroninae are restricted to the continental shelf (0-200 m), and live mostly in the upper 100 m. All species are benthic, but occasionally specimens are collected above the bottom. Members of both subfamilies appear restricted to tropical and temperate waters. The genus
Asteropella with 10 species, in addition to 2 left in open catagory, is endemic to American waters. The monotypic genera
Pteromeniscus and
Omegasterope have been collected only off west Africa. Species of
Microasteropteron have been collected only in the Indo-Pacific Region. Faunal resemblances between regions are discussed. The relationship between clutch size and carapace size in the Cylindroleberididae is similar to that in the Cypridinidae and Philomedidae. Ontogenetic development, sexual dimorphism, dimorphism between the adult and juvenile stage are investigated, and the comparative morphology of the various taxa under study is discussed in detail.