Archive for September 11th, 2015

Wooster’s Fossil of the Week: A starry bryozoan from the Upper Ordovician of southern Ohio

September 11th, 2015

Constellaria polystomella Liberty Formation 585At this time of the year I pick out one interesting specimen from the fossils my Invertebrate Paleontology class collected on their first field trip into the Upper Ordovician of southern Ohio. They did so well this week that I may be choosing a few more later! Our Fossil of the Week is the above bryozoan given the beautiful name Constellaria polystomella Nicholson, 1875. It was found by Jacob Nowell at the Caesar Creek Emergency Spillway in the Liberty Formation.
Constellaria Liberty closerConstellaria is a beautiful form, and one of the easiest bryozoans to recognize. Like all bryozooans, it was a colonial invertebrate with hundreds of filter-feeding individuals (zooids) housed in tiny tubes called zooecia. In Constellaria some of the zooecia are regularly grouped together and raised into star-shaped bumps called monticules. (The name Constellaria is clever.) This genus is a cystoporate bryozoan in the Family  Constellariidae.
JD Dana by Daniel Huntington 1858I was surprised to learn that Constellaria was named in 1846 by James Dwight Dana (1813-1895), one of the most accomplished American scientists of the 19th Century. He is best known for his Manual of Mineralogy (1848) which is still in print (greatly revised) and known as “Dana’s Mineralogy”. Dana (shown above in 1858) studied geology on scales from crystal structures to continents, with volcanoes and mountain-building in between. He had an affinity for “Zoophytes” (animals that appear to be plants), thus entangled him briefly with bryozoan systematics. Dana was born in Utica, New York, and attended Yale College, working under Benjamin Silliman, a famous chemist and mineralogist. After graduating from college he had a cool job teaching midshipmen in the US Navy, sailing through the Mediterranean in the process. For four years he served in the United States Exploring Expedition in the Pacific region. He made numerous important geological observations in Hawaii and the Pacific Northwest that he later published in books and papers. He even dabbled in theology with books like Science and the Bible: A Review of the Six Days of Creation (1856). Dana died in 1895 having received numerous accolades and awards for his research and writing.


Brown, G.D., Jr., and Daly, E.J. 1985. Trepostome bryozoa from the Dillsboro Formation (Cincinnatian Series) of southeastern Indiana. Indiana Geological Survey Special Report 33: 1-95.

Cutler, J.F. 1973. Nature of “acanthopores” and related structures in the Ordovician bryozoan Constellaria. Living and Fossil Bryozoa. Academic Press, London, 257-260.

Dana J.D. 1846. Structure and classification of zoophytes. U.S. Exploring Expedition 1838-1842, 7: 1-740.