Diurodrilus

Diurodrilus is a genus of tiny marine animals classified as orbiniid annelid worms. With a maximum length of 0.45 mm, it has an unusual morphology with many traits not found in other annelids, including a ventral creeping foot. Analyses of DNA have both refuted and supported placement within the annelids, with the unusual morphology perhaps due to evolutionary progenesis, in which organisms develop sexual maturity while retaining the larval traits of their ancestors.

The following species are recognised: Diurodrilus minimus Remane, 1925 Diurodrilus ankeli Ax, 1967 Diurodrilus benazzii Gerlach, 1953 Diurodrilus dohrni Gerlach, 1952 Diurodrilus subterraneus Remane, 1934 Diurodrilus westheidei Kristensen & Niilonen, 1982