Wooster’s Fossil of the Week: A Conulariid (Lower Carboniferous of Indiana)

I have some affection for these odd fossils, the conulariids. When I was a student in the Invertebrate Paleontology course taught Dr. Richard Osgood, Jr., I did my research paper on them. I had recently found a specimen in the nearby Lodi City Park. It was so different from anything I had seen that I wanted to know much more. I championed the then controversial idea that they were extinct scyphozoans (a type of cnidarian including most of what we call today the jellyfish). That is now the most popular placement for these creatures today, although I arrived at the same place mostly by luck and naïveté. (I love the critical marks in that word! And yes, I always have to look them up.)

The specimen above is Paraconularia newberryi (Winchell) found somewhere in Indiana and added to the Wooster fossil collections before 1974. (The scale below it is in millimeters.) A close view (below) shows the characteristic ridges with a central seam on one of the sides.
Conulariids range from the Ediacaran (about 550 million years ago) to the Late Triassic (about 200 million years ago). They survived three major extinctions (end-Ordovician, Late Devonian, end-Permian), which is remarkable considering the company they kept in their shallow marine environments suffered greatly. Why they went extinct in the Triassic is a mystery.

The primary oddity about conulariids is their four-fold symmetry. They had four flat sides that came together something like an inverted and extended pyramid. The wide end was opened like an aperture, although sometimes closed by four flaps. Preservation of some soft tissues shows that tentacles extended from this opening. Their exoskeleton was made of a leathery periderm with phosphatic strengthening rods rather than the typical calcite or aragonite. (Some even preserve a kind of pearl in their interiors.) Conulariids may have spent at least part of their life cycle attached to a substrate as shown below, and maybe also later as free-swimming jellyfish-like forms.

It is the four-fold symmetry and preservation of tentacles that most paleontologists see as supporting the case for a scyphozoan placement of the conulariids. Debates continue, though, with some seeing them as belonging to a separate phylum unrelated to any cnidarians. This is what’s fun about extinct and unusual animals — so much room for speculative conversations!

[Thanks to Consuelo Sendino of The Natural History Museum (London) for correcting the age range of these fascinating organisms.]

References:

Hughes, N.C., Gunderson, G.D. and Weedon, M.J. 2000. Late Cambrian conulariids from Wisconsin and Minnesota. Journal of Paleontology 74: 828-838.

Van Iten, H. 1991. Evolutionary affinities of conulariids, p. 145-155; in Simonetta, A.M. and Conway Morris, S. (eds.). The Early Evolution of Metazoa and the Significance of Problematic Taxa. Cambridge University Press, Cambridge.

[Modified from an original post on July 31, 2011]

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.
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7 Responses to Wooster’s Fossil of the Week: A Conulariid (Lower Carboniferous of Indiana)

  1. Cynthia Morehead says:

    I found one of these in Kentucly {Cumberland CO., impression in limestone} while on a field trip in 1996. I never knew what It was until now. I’m always happy to be able to identify my unknown specimens. It is the only one I have ever seen in person or anywhere except for a picture. Thanks.

  2. Mark Wilson says:

    I’m glad this was helpful, Cynthia. Hope you keep collecting!

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

  4. Vic Lucarelli says:

    I find one edge of this fossil every now and then in the silica shale in Sylvania, OH. I never knew what it was until now. Thanks.

  5. Seth Leedy says:

    My daughter located one just outside Wooster, Ohio in a creek bed. This seems to be the only Google location that has pictures of it. Imagine my surprise that it is a website from the city I live in !

  6. Solius says:

    I too have pulled only one conulariid from Kentucky rocks, though mine was from the central part of the state(Ordovician Clays Ferry Fm.). I lucked upon it while chopping a few disparid crinoids(Columbicrinus sp.) from a large slab back in the 80s.

  7. Michael Blair says:

    I have found about a half dozen conulariid in the Cuyahoga Formation just off of State Route 82 in Broadview Heights, Ohio back in the 1980s. A local company was excavating for a landfill and left the tailings on a nearby open parcel. They varied in size from 1-inch long ~1/2 inch-wide to a large one ~5 inches long & 1.5 -3 inches wide. Best one I found had both a cast and the mold. Really interesting looking fossils.

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