The Photographic Checklist of the Orthocladiinae of the Niger Delta, Nigeria

Aims: Compilation of the photographic checklist of the Chironomids under the subfamily Orthocladiinae from the Niger Delta of Nigeria. The compilation used records of specimens collected over a period of thirty years from many field trips.

Study Design and Methodology: The photographic keys were described to show the cephalothorax with mentum, mandibles, premandibles and ventromental plates. Orthocladiinae larvae collected from different substrates with different sizes of pond nets were preserved in 75% alcohol. Slide mounted samples were identified to genus and species. Optimal photography was obtained using a Brunnel digital microscope (DN-117M) equipped with a Camera system and a ScopeImage 9.0 software, allowing automated retention of focused parts and a sequence of exposures at different focal depths.

Results: A total of thirty six illustrations, consisting of six genera and ten species, were documented. These were Cricotopus sylvestris, Cricotopus sp., Cricotopus fuscus, Cricotopus triannulatus, Diamesa sp., Diamesa heterodentata, Eukiefferiella sp., Heterotanytarsus sp., Trissocladius grimshawi, Limnophyes pusillus and Trissocladius sp. Cricotopus sylvestris, Cricotopus sp., Cricotopus fuscus, Cricotopus triannulatus, Diamesa sp., Diamesa heterodentata, and Eukiefferiella sp. occur in lotic waters. Those that occurred only in lentic waters were Heterotanytarsus sp., Trissocladius grimshawi, Limnophyes pusillus and Trissocladius sp. Three of the genera recorded in the literature of studies in the Niger Delta, namely Cricotopus, Eukiefferiella and Limnophyes, are in the current description while new genera to the literature of the Niger Delta were Heterotanytarsus, Trissocladius and Limnophyes.

Conclusion: This photographic checklist provides additional contribution to the taxonomic metadata of the Chironomids of the Niger Delta. This can be used to provide new insights in water quality management.