Original paper

Descriptions of copepodid and adult Acanthocyclops trajani (Mirabdullayev Defaye 2002) and A. einslei (Mirabdullayev Defaye 2004) (Copepoda: Cyclopoida) with notes on their discrimination

Bláha, Martin


The copepodid phases and adults of Acanthocyclops trajani and Acanthocyclops einslei were studied to record their distinguishing characteristics. Morphological examination showed that copepodids of both species were very similar, and showed an identical pattern of articulation and ornamentation of appendages and antennules. Differences in the distal endopodid of the fourth swimming leg and antennal ornamentation were found in later stage copepodids of both species. A. trajani had a higher ratio of apical spines on the distal endopodid of the fourth swimming leg compared to A. einslei, as well as a higher segment length/width ratio, and site of lateral spine insertion, which is more distal in A. einslei compare to A. trajani. Based on morphological descriptions of the copepodids of A. trajani and A. einslei, reported in this study, discrimination of later stage copepodids is feasible and may serve as a tool for basic ecological studies of zooplankton communities that is not dependent on the presence of adult specimens.