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Böttger-Schnack, R.; Schnack, D. (2015). Development of an interactive identification key for Oncaeidae (Copepoda: Cyclopoida). Journal of Natural History. 49(45-48): 2727-2741.
Böttger-Schnack, R.; Schnack, D.
Development of an interactive identification key for Oncaeidae (Copepoda: Cyclopoida)
Journal of Natural History
The current state of development of an interactive electronic identification key for the marine pelagic microcopepod family Oncaeidae is presented. To date, 112 species have been described, which are allocated to 7 genera (Archioncaea, Epicalymma, Conaea, Monothula, Oncaea s.str., Spinoncaea, and Triconia) and 16 species groups, defined within the speciose paraphyletic taxon Oncaea s.l. Only two species of Oncaea s.l. show an uncertain group status. Of all described oncaeids, seven species are not yet included in the key due to insufficient or contradictory morphological description and/or lack of type material for re-examination. In addition, seven morphologically distinct species and two new species groups are considered, which have not been formally described yet. The key is restricted to females at present. It uses easily distinguishable morphological characters as far as possible (e.g. body size, proportional lengths of urosomites, length of P5 exopod) and includes more difficult characters (e.g. spine counts on swimming legs, proportional spine lengths) where required for unequivocal identification. The chosen characters allow identifying at least genera and species groups with limited experience, while separation of species requires in some cases more advanced dissection skills. Potential identification problems due to difficulties in discerning minute morphological features and uncertainties in length values and ratios related to intraspecific variability are discussed. The present version of the identification key still requires complementing illustrations of feature states and inclusion of so-called “fact sheets”, summarizing the characteristics of each species, including notes on controversial taxonomic issues of the respective taxon and links to databases providing species specific zoogeographical and genetic information.
Identification key, Expert Identification Systems