Body length of female Macrosetella gracilis (Copepoda: Harpacticoida) from various depth zones in the Red Sea

Body length of female A4acrosetella gracilis was analysed at different depths, in varlous regions and during 2 seasons in 1980-81 In the Red Sea. Two d~stlnct size groups, >1.2 mm and <1.2 mm, were present. A literature review suggests that the smaller size group (mode length ca 1.1 mm) 1s restr~cted mainly to the Red Sea. Possible causes for the formation of M. gracrlis size morphs are discussed.