Does anyone have experience with the Middle Ordovician brachiopod faunas of the upper Mississippi Valley? I came across this odd fragment in rocks from a quarry in south-central Wisconsin. To my knowledge they are known in North America only from the Appalachian Basin (Tennessee, Virginia, West Virginia, Pennsylvania, Quebec, Newfoundland), not the interior basins like the Illinois basin. Has anybody else seen this critter or similar in the Platteville?
As far as I am aware, the only species documented from the Platteville that looks anything like this is Megamyonia unicostata, but that has a single costa rather than the several apparent here and in the types of Ptychoglyptus.
Platteville Fm, probably in P. undatus biozone
= Upper Ordovician, Sandbian stage (old North American Turinian Stage)