Wooster’s Fossil of the Week: A spiriferid brachiopod (Middle Devonian of northwestern Ohio)

I begin my Invertebrate Paleontology course by giving each student a common fossil to identify “by any means necessary”. This year I gave everyone a gray little brachiopod, one of which is shown above. They did pretty well. Kevin Silver (’13) got it down to the genus quickly. Turns out a Google image search on “common fossil” is very effective!

This is Mucrospirifer mucronatus (Conrad, 1841), a beautiful spiriferid brachiopod from the Silica Shale Formation (Middle Devonian) of Paulding County, northwestern Ohio. I collected it and many others at a quarry on a crisp October day with my friend and amateur paleontological colleague Brian Bade.

The image at the head of this page is a view of the dorsal valve exterior of Mucrospirifer mucronatus; the image immediately above is the ventral valve exterior. Spiriferid brachiopods like this are characterized by extended “wings” and a long hingeline. Inside was their defining feature: a spiral brachidium that held a delicate tentacular feeding device known as the lophophore.

This is the anterior of our brachiopod. The fold in the middle helped keep incurrent and excurrent flows separate, enabling more efficient filter-feeding. (By the way, have you noted the quirky asymmetry of this specimen?)

A view of the quarry that yielded our Fossil of the Week. Note the happy amateurs picking through blast piles of the Silica Shale Formation (Middle Devonian).

A pond in the quarry. It has an unexpected beauty, muddy as it is.

Timothy Abbott Conrad (1803-1877) described Mucrospirifer mucronatus in 1841. We met him before when discussing a siliquariid gastropod. He was a paleontologist in New York and New Jersey, and a paleontological consultant to the Smithsonian Institution.

Reference:

Tillman, J.R. 1964. Variation in species of Mucrospirifer from Middle Devonian rocks of Michigan, Ontario, and Ohio. Journal of Paleontology 38: 952-964.

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
This entry was posted in Uncategorized and tagged , , , . Bookmark the permalink.

3 Responses to Wooster’s Fossil of the Week: A spiriferid brachiopod (Middle Devonian of northwestern Ohio)

  1. Pingback: Wooster Geologists » Blog Archive » Wooster’s Fossil of the Week: A conulariid from the Upper Ordovician of Indiana

  2. Dave says:

    Hi, I am looking to find mucrospirifer brachiopods. I know they are in Michigan Ohio and Ontario. Can you tell me of a place to find them. They are very cool looking. Thanks, Dave

  3. Olivia says:

    Dave, I’ve found a couple good specimens at a bend in a creek bed in Southeast Michigan among pebbles. Now/winter is a great time of year to look for them near/in creeks, as the water level is lower than normal most days and there aren’t any bugs.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.