Diurodrilus

Diurodrilus is a genus of tiny marine animals classified as orbiniid annelid worms.^[1] 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.^[2][3] Analyses of DNA have both refuted and supported placement within the annelids,^[3][4] with the unusual morphology perhaps due to evolutionary progenesis, in which organisms develop sexual maturity while retaining the larval traits of their ancestors.^[4]

Diurodrilus
Scientific classification
Kingdom:	Animalia
Phylum:	Annelida
Order:	Orbiniida
Family:	Diurodrilidae Kristensen & Niilonen, 1982
Genus:	Diurodrilus Remane, 1925
Type species
Diurodrilus minimus Remane, 1925
Species
D. minimus Remane, 1925 D. ankeli Ax, 1967 D. benazzii Gerlach, 1953 D. dohrni Gerlach, 1952 D. subterraneus Remane, 1934 D. westheidei Kristensen & Niilonen, 1982

The following species are recognised:^[3][5]

• 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