Hyolithellus

{{Short description|Genus of annelids (fossil)}}

{{Automatic taxobox

| fossil_range = {{fossil range | Lower Cambrian | Middle Cambrian | ref = }}

| taxon = Hyolithellus

| authority = Billings, 1871

}}

Hyolithellus is a conical tubular fossil from the Cambrian, originally considered a hyolith but since reinterpreted tentatively as an annelid worm.{{cite journal |author=Christian B. Skovsted & John S. Peel |year=2011 |title=Hyolithellus in life position from the Lower Cambrian of North Greenland |journal=Journal of Paleontology |volume=85 |issue=1 |pages=37–47 |doi=10.1666/10-065.1|bibcode=2011JPal...85...37S |s2cid=129124366 }}

Its circular, thin (15–150 μm), originally phosphatic tube gets wider along its long, undulating, annulated length.