Unusual parasitic markings on crinoid column

   

General abundance:  Rare

I have only found four (4) out of hundreds of crinoid columns,
with these unusual markings.

Viewer Comments:

I have observed these kinds of markings on crinoid stems from
a number of areas in the midcontinent and have categorized
a lot of them in a couple of papers I have in preparation. I have
seen them on crinoids from the Barnsdall Formation (Virgilian)
of northeastern Oklahoma and from crinoids from the Stanton
Formation in Nebraska, Kansas and Oklahoma. To my knowledge,
I've only observed this kind of (boring?, cut?, gouge?) on stems
of crinoids. I do not recall having seen them of cups or cup plates.
They may be where sponges anchored to the crinoid. I've not
seen any with an alignment that would suggest a bite from a
fish or cephalopod. I've categorized these kinds of things as
encrusters, borers, slashers, rovers, In some cases, where one
has found a lot of some kinds of markings on crinoids, specimens
have been dissolved in acetic or formic acid and phosphatic teeth
or radulae have been found in the residue, suggesting myzostome
worms. Unfortunately, a lot of paleontologists have simply
attributed these markings to myzostomes and I think there are
many more commensals, parasites, or predators that have left
marks on crinoids. I would suggest that you might keep some kind
of score card or tally on what parasites, predators or commensals
have left their calling cards on all of the fossils you've collected
from the Lake Neosho. This kind of data, though tedious to gather,
can really help paint a picture of a very dynamic ecosystem that is
preserved in the fossil assemblage you are finding there.
Dr. Roger K. Pabian

Those unusual markings on your crinoid stem are from
parasites which bore into the stem. They are parasitic
borings. They aren't common as you stated. There is
a site in Texas where there are a higher than usual ratio
of parasitic bored stems to "clean" stems. There are
different forms undoubtedly because there were different
species of parasites whom caused the borings.
I hope this explanation helps you.
Mark Palatas

Parasitic Menu
Fossil Menu

Pennsylvanian Fossils of Missouri