ANNiKEY Linear - diagnoses, descriptions, and a single-access identification key to Annelida family-level taxa.

Phylum Annelida are ubiquitous metazoans found in almost every terrestrial and aquatic habitat on Earth. Historically, taxonomic studies on the phylum have been focused largely on its majorgroups, polychaetes, oligochaetes and leeches, so that while family-level keys for each group are available, no single-source identification guide exists to the world's annelid families. Here, the first illustrated linear key to annelid families is provided and family-level descriptions and diagnoses that distinguish individuals of each family from those of other families in the phylum are updated. This information is generated from an annelid DELTA database of 334 characters and 166 mostly family-level taxa. A link is provided to downloadable software (ANNiKEY Interactive) allowing the same data to be interrogated using the open-source DELTA program Intkey, which enables both interactive identification and taxonomic query functionality. For each family-level taxon, a diagnosis, full description, links to taxonomic data at the World Register of Marine Species, illustrations of diagnostic features, and a summary of the recent literature, including a list of published keys to genera and species are provided.