Extension of the taxonomic resolution of the marine microcopepod family Oncaeidae and development of an interactive identification system

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The microcopepod family Oncaeidae is one of the most abundant and diverse metazoan families in oceanic zooplankton communities. Their position and function in the pelagic ecosystem is yet insufficiently known, however. The species identification within this highly diverse family, which presently includes more than 100 species, is very uncertain worldwide, because the number of morphologically similar sister or sibling species occurring in different regions of the world ocean is inadequately known to date. There are few identification keys available, all of which which are regionally limited, do not cover the entire species spectrum occurring in a given region and/or are deficient due to the lack of taxonomic expertise. This limitation leads to erroneous diagnoses during species identifications in ecological studies in an alarming extent, coupled with the danger of spreading and magnifying these errors in other applied biological disciplines.In order to enable a secured identification of oncaeid species and/or species groups in the world ocean and an appropriate consideration in ecological studies, it is necessary to compile the published morphological data of all over 100 species of Oncaeidae described to date, to define the morphological criteria which are necessary for an unequivocal identification and to build up an interactive identification system based on these data. The generic classification system of the Oncaeidae is insufficiently resolved so far, therefore a reasonable definition of species groups is necessary in particular for the heterogeneous genus Oncaea s.l., which will be based on phylogenetic relevant characters.The aim of the present project is the development of a relational database, by means of which a flexible and expandible system for the taxonomic grouping and computer-aided identification of the family Oncaeidae in the world ocean shall be build up. This tool is required for a secured identification of one of the most important pelagic microcopepod families in the world ocean to be used in basic and applied ecological studies, in biodiversity analyses, monitoring and environmental management programmes. As an example for a regional system the European Mediterranean Sea will be included, which is of fundamental significance for the taxonomy of Oncaeidae, as many (more than 40) species have been found here and this area represents the original locality (locus typicus) of many of the smaller oncaeid species, which are still insufficiently described. Therefore, in the worldwide context the exact identification of species from this area is essential for further taxonomic and comparative regional studies.