Follow-up: Pipestone National Monument, Scenella, Cylindrocoelia

Here's a little more information on a few enigmas from previous posts, with some additional photos from the University of Minnesota paleontological collections. First up is Pipestone National Monument's "Lingula calumet", then Scenella, and finally Cylindrocoelia minnesotensis.

Hyoliths and Scenella

One of the aspects of Paleozoic fossils you learn to appreciate is just how many groups had a brief moment in the sun and then disappeared. I'm not just talking about famous things, like trilobites or ammonites (which saved their best for the Mesozoic, of course). You couldn't wade around in an Ordovician sea without crushing or disturbing something that has no living relatives. In fact, given the diminutive size of most of these things, you would probably endanger an entire fauna with each step, so by all means be careful next time you happen to swing by the Ordovician. Today's spotlight shines on two groups that hang around the fringes of Mollusca, and which show up in small numbers in the Ordovician of the Twin Cities: the hyoliths and scenellids.