Serpulid worm tubes

Mississippian
Meramecian Series
Warsaw Formation
St. Louis County, Missouri

Serpulid worm tubes on an Archimedes

Thanks to Andrew Dunham and Tom Yancey for solving the
mystery of what these tube shapes might represent.

Viewer Comments #1

It certainly looks like a serpulid worm tube to me. You can
find information on Serpulid worm tubes in most general
fossil publications, though I've never found a reference specific
to them. I imagine the Treatise on Invertebrate Paleontology
probably has a decent section on them (though I have not checked).
The Aududon's Field Guide to NA Fossils has a brief section; that
at least should fall quickly to most any hand. Checking- it says that
Serpulid worm tubes are uncommon prior to Cretaceous, but I've
found them on several Pennsylvanian ammonite shells.

Phylum Annelida
Class Polychaeta
Order Sabellida
Family Serpulidae

Segmented worms; sessile, CaCO3 tube dwellers with ciliated
"feathery" tentacles used for plankton feeding and gas exchange.
Often colonial, secreting their tubes on shells, rocks and other
stable surfaces.

Hope that helps.
Andrew Dunham

Viewer Comments #2

It is a worm tube, or group of tubes. The Archimedes colony has
partly overgrown the tubes, probably because of the disturbance
irritation caused by the presence of the worms. Such overgrowth
shows that the settlement occurred while the bryozoan was alive.
Such settlement and overgrowth features are common in modern
corals.

Small diameter tubes like this are given the name Spirorbis, when
they are found as small partly coiled tubes. Because these have
been overgrown, the early portions are not visible and the later
portions do not have a distinctive form.

Dr. Tom Yancey

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Warsaw Formation

Mississippian Fossils of Missouri