The microcopepod fauna in the Gulf of Aqaba, northern Red Sea: species diversity and distribution of Oncaeidae (Poecilostomatoida)

A total of 23 species and three groups of form variants of oncaeidcopepods have been identified, which were collected in smallmesh net samples taken along a transect from the northernmostRed Sea (>27°N) to the Gulf of Aqaba down to a maximumdepth of 800 m. Two of the species were present only in theRed Sea main basin, but were not recorded in the Gulf. By comparingthe present results with previously published data from thecentral and southern Red Sea a first assessment of the zoogeographicaldistribution of Oncaeidae in the entire Red Sea has been achieved.The species diversity of Oncaeidae in the Gulf of Aqaba appearsto be considerably lower compared to the southern Red Sea, where31 oncaeid species and four groups of form variants have beenfound. The observed latitudinal gradient in species numbersof Oncaeidae generally corresponds to the gradients observedfor various other zooplankton taxa in the Red Sea. First dataon the vertical distribution of oncaeid species in the Gulfare provided.