Earthworm Attack

Within the world of taxonomy the stable 'Classical System' of Michaelsen (1900) and Stephenson (1930) was gradually eroded by the controversy over how to classify earthworms such that Fender and McKey-Fender (1990) went so far as to say "The family-level classification of the megascolecid earthworms is in chaos." Over the years, many scientists developed their own classification systems for earthworms, which led to confusion, and these systems have been and still continue to be revised and updated. The classification system used, developed by Blakemore (2000), is a modern reversion to the Classical System that is historically proven and widely accepted.
Categorization of a megadrile earthworm into one of its taxonomic families under suborders Lumbricina and Moniligastrida is based on such features as the makeup of the clitellum, the location and disposition of the sex features (pores, prostatic glands, etc.), number of gizzards and body shape. There are currently over 6,000 named species of terrestrial earthworms, as provided in a species name database, but the number of synonyms is unknown.
The families, with their known distributions or origins: