Taxonomy of the Lysianassoidea of the Northeast Atlantic and Mediterranean : an interactive identification key and studies on problematic groups

Abstract

A DELTA (DEscriptive Language for TAxonomy) database was constructed for 135 species of lysianassoid amphipods of the Northeast Atlantic and Mediterranean Sea, representing almost 20% of the total estimated number of amphipod species from this region. The database utilised 97 characters to output an illustrated, interactive species-level identification key to the taxon. This is presented in electronic format on the accompanying CD. Generally, images were copied from literature sources after formal copyright permission had been obtained. However, in many cases it was necessary to illustrate specimens, as adequate images could not be found in the literature. In some cases scanning electron micrographs were taken of some of the surface and sensory structures of the animals. These are also presented in the key. The key will be published on the amphipod website www.amphipoda.com, and the crustacean website www.crustacea.net. Also generated by DELTA was an associated descriptive monograph for each species. This is also presented electronically, as well as in a supplemental volume accompanying the thesis. In addition, details of new species records for Irish waters are given. Among these is a new species, Tryphosella lowryi, which is described, and this genus in the British Isles is reviewed. Another new record for the area is Orchomenella crenata, and this is re-established as a valid species. Finally the genera Normanion and Sophrosyne in the north Atlantic were recognised as particularly problematic and are here revised.