Delineating species boundaries correctly is crucial to the discovery of life's diversity because it determines whether or not different individual organisms are members of the same entity. The gap in communication between the different disciplines currently involved in delimiting species is an important and overlooked problem in the so-called 'taxonomy crisis'. To solve this problem, it is suggested that taxonomy become integrative, and this integration is seen as the real challenge for the future of taxonomy. 'Integrative taxonomy' is defined as the science that aims to delimit the units of life's diversity from multiple and complementary perspectives (phylogeography, comparative morphology, population genetics, ecology, development, behaviour, etc.). Some workers have already collaborated and successfully adopted an integrative approach to taxonomy. However, it is now time for the whole discipline to evolve. A radical change in mentality is needed concerning the creation of names in order to achieve this integration and to prevent the over-abundance of both synonyms and names of doubtful application from worsening. Integrative taxonomy gives priority to species delineation over the creation of new species names. Furthermore, it is emphasized that describing morphological diversity, referred to as 'morphodiversity', does not require the naming of any single set of specimens. Seven guidelines are proposed to help integrative taxonomists recognize cases when species are supported by broad biological evidence and therefore are deserving of an official name. (c) 2005 The Linnean Society of London.