Waiting for the revised FAO Catalog can test one's patience, so next best may be this Field Guide issued by Harper Collins. The text portion is FAO-lite, with brief overviews, including line-drawings (of the individual and one or more teeth) and maps, of well over 400 species (closer to 450 if undescribed taxa are included). Supplementing this handy reference are 64 excellent color plates by Marc Dando and a most appreciated updated checklist by LJVC.

Lacking is a bibliography which can be frustrating with newer taxa, but this is readily overshadowed by the usefulness of the Biology, Glossary and other field guide-like prerequisites incorporated in this book -- which is really quite impressive.

Listed at £25, this book can be obtained directly from Harper Collins or from Amazon