LARVAL DEVELOPMENT OF LAMPANYCTUS SPECIES (PISCES, MYCTOPHIDAE) FROM THE SOUTHWESTERN INDIAN-OCEAN, AND SPECIES GROUPS BASED ON LARVAL CHARACTERS

Ten species belonging to the genus Lampanyctus were found among the fi sh larvae collected in the Agulhas Current region during a pilot study and three cruises carried out during 1989-1991. Six were identified t o species level: L. achirus, L. alatus, L. ater, L. lepidolychnus, L. nobilis and L. pusillus. Individuals of four other species were differ entiated, but they were too small to show the meristic or photophore c haracters that allow species identification with complete confidence. The most probable identifications of these four species as L. festivus , L. turneri, L. lineatus, and a species of the L. regalis-ater group, is discussed in the paper. Detailed descriptions of larval developmen t are given for those species with previously unknown early life histo ry stages, together with a discussion of the characters on which the i dentifications were based. Information on the characters that allow di fferentiation of all the Lampanyctus larvae that may occur in the Sout hwestern Indian Ocean is also given. A brief description of L. austral is larvae from the northern Benguela region is therefore also included . Larval characters of other Lampanyctus species, obtained from the li terature or determined after examination of samples obtained in other geographical areas, were used together with the present information, t o study affinities between species. Three very dissimilar groups of sp ecies were differentiated. The most similar species were L. crocodilus , L. australis and L. alatus.