Taxonomic revisions of diverse groups of organisms are challenging because they generally require efficient management and synthesis of large amounts of nomenclatural, morphological, and distributional data. When undertaken using traditional methodologies, such projects often require many years to yield publishable results. Technological advances, including relational databases, digital imaging, and Internet dissemination, provide the means to overcome some of the logistical problems inherent to revisions of highly speciose taxa, and provide systematists with tools to increase both the quality and quantity of such studies.

3I (Internet-accessible Interactive Identification) is a set of software tools intended to facilitate the efficient production of Internet-based virtual taxonomic revisions and published monographs. The package facilitates storage, retrieval and integration of taxonomic nomenclature, specimen-level data on distribution, ecological associations, morphological character, associated illustrations, and bibliographic information. These data are stored in a customized MS Access database. Web interfaces for specialized querying of the database were developed using ASP (Active Server Pages) programming technology. These interfaces include simple and advanced searches on any field in the database, and interactive keys designed to include attributes similar to those of Delta IntKey and Lucid (two popular programs for development of interactive keys). The main features of 3I keys are the following: 1) 3I keys are multi-entrance polytomous keys, with unlimited number of characters, character states, and taxa; 2) after each step of identification the characters not relevant for further identification are removed from the list, not relevant states are marked; 3) 3I keys support numeric characters; 4) the characters in key can be sorted by morphology, by rank (assigned by the author), or by separating power recalculated after each step of identification; 5) characters can have hyperlinks to explanatory images; 6) a key can handle taxa of different hierarchical levels, and the software can also generate keys for higher hierarchical level taxa, based on data matrix scored for taxa of lower hierarchical level; 7) uncertainties and user-specified error tolerance are allowed during identification; 8) phenetic trees are generated from the morphological data, or the data matrices can be exported in a format suitable for phylogenetic analysis and 9) 3I has an utility to convert interactive keys into conventional ones.

Clicking on a taxon name in the search or key interface opens another browser window that displays a complete taxonomic treatment of the taxon generated on the fly from the underlying database. The listing is organized as it might appear in a published monograph, including synonymy, description, distribution map, list of specimens examined and table of associations (for species only) and bibliography. For higher taxa, the taxon treatment includes a link to an interactive key to the included subordinate taxa. Because 3I is web-integrated with database queries performed on the server side, the web interfaces are stable and are compatible with virtually any computer operating system/browser combination.

More information and examples of the interactive keys ant taxonomic databases developed using 3I are available from http://ctap.inhs.uiuc.edu/dmitriev/.