Wooster’s Fossil of the Week: A bryozoan etching (Upper Ordovician of Indiana)

February 24th, 2013

Ropalonaria_venosa_585_010213Another trace fossil of a sort this week. Above you see the dorsal valve exterior of a strophomenid brachiopod from the Upper Ordovician of southeastern Indiana. Across the surface is a network of grooves looking a bit like a spider web. This is a feature formed when a soft-bodied ctenostome bryozoan colony etched its way down into the shell it was encrusting. Ropalonaria venosa Ulrich, 1879 is the official name of this fossil.
Ropalonaria_close_010513Above is a closer view of the same Ropalonaria venosa. Tiny crystals of yellow dolomite fill the excavations. The ctenostome bryozoan that made it had no skeleton and used some sort of chemical to dissolve the shell beneath it. The fidelity of this etching is good enough to identify various details of the colony structure and zooecial form. This is where our fossil classification system goes a bit awry: Is Ropalonaria a trace fossil (evidence of animal activity) or a kind of external mold of the original organism? Arguments have been made for each category, and the name Ropalonaria shows up on lists of both trace fossils and body fossils.
Ulrich_EO_1927Ropalonaria venosa is the type species of the genus Ropalonaria erected by Edward Oscar Ulrich in 1879 (above in 1927). E.O. Ulrich, as he is better known, was one of the most colorful and controversial geologists of the late 19th and early 20th century. He was born in Covington, Kentucky, in 1857. Covington is across the Ohio River from Cincinnati, Ohio, and is undergirded by the famous fossiliferous limestones and shales of the Cincinnatian Group (Upper Ordovician). Ulrich started as a child collecting fossils in the region. He was an early member of the Cincinnati Society of Natural History, often bringing fossils to meetings for identifications. (There he met another young man very interested in fossils: the future paleontologist Charles Schuchert. Schuchert was the advisor of my advisor’s advisor, so he’s in my “academic genealogy”.)

Ulrich took courses at German Wallace College (today’s Baldwin Wallace University in Berea, Ohio) and the Ohio Medical College. He had an eclectic youth exploring all sorts of topics, from opera to spiritualism, but always kept geology and fossils close to his heart. He had an adventurous stint as a superintendent in a Colorado silver mine. Returning back east, Ulrich became an enormously productive geologist with the geological surveys of Illinois, Minnesota, and Ohio. He was President of the Paleontological Society in 1915. In 1931 he received the Mary Clark Thompson Medal from the National Academy of Sciences, and the next year the Geological Society of America awarded him the prestigious Penrose Medal. He died in 1944 in Washington, D.C.

E.O. Ulrich is still a polarizing figure in American geology. He is famous for resisting the modern concept of facies in sedimentary geology, preferring a concept now known as “layer cake stratigraphy“. (In his defense, the rocks in the Cincinnati area really do fit much of his model; his error was extending it much too far.) Ulrich also has a reputation as a bit of a “splitter” in paleontology. (Someone who makes more species than necessary by “splitting” groups into smaller subgroups.)

Despite what we think of E.O. Ulrich today, his paleontological contributions have mostly held up, including the description of the intriguing fossil Ropalonaria.


Bassler, R.S. 1944. Memorial to Edward Oscar Ulrich. Proceedings of the Geological Society of America for 1944: 331–351.

Pohowsky, R.A. 1978. The boring ctenostomate Bryozoa: taxonomy and paleobiology based on cavities in calcareous substrata. Bulletins of American Paleontology 73(301): 192 p.

Ruedemann, R. 1946. Biographical memoir of Edward Oscar Ulrich, 1857-1944. National Academy of Sciences of the United States of America. Biographical Memoirs, Volume XXIV, 7th Memoir, 24 pp.

Ulrich, E.O. 1879. Descriptions of new genera and species of fossils from the Lower Silurian about Cincinnati: Journal of the Cincinnati Society of Natural History 2: 8-30.

Wooster’s Fossil of the Week: A very thin coral from the Upper Ordovician of Indiana

February 3rd, 2013

Protaraea111712What we have above is a heliolitid coral known as Protaraea richmondensis Foerste, 1909. It has completely encrusted a gastropod shell with its thin corallum. Stephanie Jarvis, a Wooster student at the time and now a graduate student at Southern Illinois University, found this specimen during her paleontology class field trip to the Whitewater Formation exposed near Richmond, Indiana.

Protaraea is a confusing taxon to my Invertebrate Paleontology students. It is a very common encruster in their Ordovician field collections, being found on hard substrates as varied as rugose corals and orthid brachiopods. It is so thin, though, that it is hard to believe it was a colonial coral. Plus it has tiny septa (vertical partitions) in its corallites (the holes that held the polyps), very unlike most corals of the heliolitid variety. This is a group the students have to identify by matching pictures and taking our word for it.

We can’t identify the gastropod underneath. Note that it has a sinus evident in the last whorl (an open slot parallel to the coiling). The coral grew right up to the edge of this sinus, preserving it and its extension through the shell.


Alexander, R.R. and Scharpf, C.D. 1990. Epizoans on Late Ordovician brachiopods from southeastern Indiana. Historical Biology 4: 179-202.

Foerste, A.F. 1909. Preliminary notes on Cincinnatian fossils. Denison University, Scientific Laboratories, Bulletin 14: 208-231.

Mõtus, M.-A. and Zaika, Y. 2012. The oldest heliolitids from the early Katian of the East Baltic region. GFF 134: 225-234.

Ospanova, N.K. 2010. Remarks on the classification system of the Heliolitida. Palaeoworld 19: 268–277.

Wooster’s Fossil of the Week: A conulariid from the Upper Ordovician of Indiana

January 6th, 2013

Conulariid123012This week’s fossil is not technically impressive: it is a rather modestly preserved conulariid from the Waynesville Formation of southern Indiana (location C/W-111). It is notable because it is one of the very few conulariids I’ve found in the Ordovician, and it gives me a chance to write about a fascinating talk three of my friends presented last month at the annual meeting of the Palaeontological Association in Dublin.

The above image is a side view of the specimen. Its identity as a conulariid is indicated by the four flat sides with gently curved ridges and the distinctive grooved corner between the two visible sides. With only this part of the conulariid visible, we can at least tentatively identify the specimen as Conularia formosa Miller & Dyer, 1878. Conulariids are most likely the polyp stages of scyphozoans (typical “jellyfish”).
CloseConulariid123012Here is a closer view of one of the sides. You can just make out a midline running parallel to the axis of the fossil slightly offsetting the ridges.
Cross1123012This is a broken cross-section through the conulariid showing the four corners and sides. Note that the fossil is symmetrical, give or take a little squishing during preservation. (The test was made of a flexible periderm, not a hard shell.)

This brings us to the presentation last month at the Palaeontological Association meeting titled: “Asymmetry in conulariid cnidarians and some other invertebrates”. It was given by Consuelo Sendino from the Natural History Museum in London, with co-authors Paul Taylor (also NHM London) and Kamil Zágoršek (Národní muzeum, Prague). The specimens below are part of a set of conulariids they studied from the Upper Ordovician (Sandbian) of the Czech Republic.
1Screen shot 2012-12-19 at 5.36.04 AMThis is Metaconularia anomala (Barrande, 1867). Note that it has a very different symmetry from the typical conulariid: it is four-sided at the base and three-sided at the top. Only a minority of specimens show this asymmetry, but why any do is a mystery.
2Screen shot 2012-12-19 at 5.36.27 AMHere are several more Metaconularia anomala specimens with various states of symmetry. All are internal molds.
3Screen shot 2012-12-19 at 5.37.02 AMThis is a summary of the symmetries present in these Ordovician conulariids. For such a simple morphology, these are surprisingly complex states. There is a pattern to this diversity: these conulariids show a kind of sinistral coiling — a directional asymmetry.

There are many questions that arise from such asymmetrical fossils. Why was the original symmetry “broken” in these individuals? Did asymmetry have adaptive value? (These aberrant individuals apparently survived to a normal size, at least.) Is this asymmetry genetically controlled or produced by the environment in some way? If there is a genetic component, has it ever had evolutionary value?

I now notice fossils that are outside normal symmetry ranges (like this Devonian brachiopod) and wonder how common and important the phenomenon is. Another paleontological wonder and mystery!


Miller, S.A. and Dyer, C.B. 1878. Contributions to Palaeontology (No. 1). Journal of the Cincinnati Society of Natural History 1, no. l, p. 24-39.

Sendino, C., Zágoršek, K. and Taylor, P.D. 2012. Asymmetry in an Ordovician conulariid cnidarian. Lethaia 45: 423-431.

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.

Van Iten, H. 1992. Morphology and phylogenetic significance of the corners and midlines of the conulariid test. Palaeontology 35: 335-358.

Wooster’s Fossil of the Week: A horn coral from the Upper Ordovician of Indiana

December 9th, 2012

This week’s fossil is a very common one from the Whitewater Formation (Richmondian, Upper Ordovician) exposed near Richmond, Indiana. It was collected, along with hundreds of other specimens, during one of many Invertebrate Paleontology field trips to an outcrop along a highway. The fossil is Grewingkia canadensis (Billings, 1862), a species my students know well because many made acetate peels of cross-sections they cut through it.

Grewingkia canadensis belongs to the Order Rugosa, a group commonly called the “horn corals” because their solitary forms (as above) have a horn-like shape. Children often think they are dinosaur teeth! It is so common in Richmondian rocks that it is sometimes used to indicate current direction. Its robust skeleton provided attachment space to many encrusting organisms, and it often has multiple borings in its thick calcite theca.

We believe that the rugose corals lived much like corals today. They sat partially buried in the sediment with the wide end of the skeleton facing upwards. A polyp sat inside the cup-shaped opening, spreading its tentacles to catch small organisms swimming by.

Grewingkia canadensis has a complicated taxonomic history. It is likely also known as Streptelasma rusticum, Grewingkia rustica, Streptelasma vagans, Streptelasma insolitum, and Streptelasma dispandum. G. canadensis is characterized by cardinal and counter septa (the vertical partitions inside the coral skeleton) that are longer than the other major septa throughout ontogeny (growth).
The handsome man shown above is, of course, a paleontologist. This is Elkanah Billings (1820-1876), Canada’s first government paleontologist and the one who named Grewingkia canadensis. (He originally placed it in the genus Zaphrentis.) Billings was born on a farm near Ottawa. He went to law school and became a lawyer in 1845. But he loved fossils and in 1852 founded a journal called the Canadian Naturalist (and Geologist). In 1856, Billings left the law and joined the Geological Survey of Canada as its first paleontologist. He named over a thousand new species in his career, and is best known for describing the first fossil from the Ediacaran biota — a critical time in life’s early history. The Billings Medal is given annually by the Geological Association of Canada to the most outstanding of its paleontologists.


Billings, E. 1862. New species of fossils from different parts of the Lower, Middle, and Upper Silurian rocks of Canada. Paleozoic Fossils, Volume 1, Canadian Geological Survey, p. 96-168.

Elias, R.J. and Lee, D.J. 1993. Microborings and growth in Late Ordovician halysitids and other corals. Journal of Paleontology 67: 922-934.

Elias, R.J., McAuley, R.J. and Mattison, B.W. 1987. Directional orientations of solitary rugose corals. Canadian Journal of Earth Sciences 24: 806-812.

The first Wooster Geology student posters at GSA 2012

November 4th, 2012

CHARLOTTE, NORTH CAROLINA–The brave souls Jonah Novek (’13) above and Kit Price (’13) below were the first Wooster students to present their posters at the 2012 Geological Society of America meeting. Jonah worked in Estonia this past summer on Early Silurian recovery faunas in the Hilliste Formation on Hiiumaa Island. You can read his abstract directly here, and you can recall his field adventures by searching for “Jonah” in this blog. Kit collected Upper Ordovician cryptic sclerobiont fossils in Indiana in the late summer. Her abstract is here, and you can see her work in this blog by searching for “Kit“. Jonah and Kit started off our GSA presentation experience with confidence and joy.

Wooster’s Fossil of the Week: a deformed brachiopod (Upper Ordovician of Indiana)

September 23rd, 2012

Kevin Silver (’13), a sharp-eyed paleontology student, found this odd brachiopod on our field trip earlier this month in southeastern Indiana. It comes from the Upper Ordovician (Katian) Whitewater Formation. Kevin correctly identified it as Vinlandostrophia acutilirata (Conrad, 1842), an orthid brachiopod formerly in the genus Platystrophia (see Zuykov and Harper, 2007). The above view is looking at the anterior of the brachiopod with the dorsal valve above and the ventral valve below.

What we see right away is that this brachiopod specimen is asymmetric: the right side is much shorter than the left. This is a feature of this individual, not the species. Is it a teratology — a deformity of growth? Probably. It is unlikely to be from post-depositional squeezing because the shell is otherwise in excellent shape. The oddity did not seem to hinder this individual from growing to a full adult size.

The same specimen looking at the dorsal valve with the hinge at the top of the image. The fold in the center is coming up towards us.

The posterior of our specimen, with the dorsal valve at the top. This is the hinge of the brachiopod.

A view of the ventral valve with the sulcus in the center.

(The above images are to help my paleontology students with their brachiopod morphology!)


Alberstadt, L.P. 1979. The brachiopod genus Platystrophia. United States Geological Survey Professional Paper 1066-B: 1-20.

Boucot A.J. and Sun, Y.L. 1998. Teratology, possible pathologic conditions in fossil articulate brachiopods: p. 506-513, Collected works of the international symposium on Geological Sciences, Peking.

Conrad, T.A. 1842. Observations on the Silurian and Devonian Systems of the United States, with descriptions of new organic remains. Journal of the Academy of Natural Sciences of Philadelphia 8: 228-280.

Zuykov, M.A. and Harper, D.A.T. 2007. Platystrophia (Orthida) and new related Ordovician and Early Silurian brachiopod genera. Estonian Journal of Earth Sciences 56: 11-34.

Wooster’s Fossils of the Week: a little sclerobiont community (Upper Ordovician of Indiana)

September 16th, 2012

Last week the students of my Invertebrate Paleontology class found many excellent fossils in the Whitewater and Liberty Formations of southeastern Indiana. We will be featuring some of them in this space. I want to start with one of my own finds: an orthid brachiopod from the Whitewater known as Vinlandostrophia acutilirata (Conrad, 1842), the inside of which is encrusted by old friends Cuffeyella arachnoidea (Hall, 1847) and Cornulites flexuosus (Hall 1847).

A sclerobiont is an organism living in or on a hard substrate. The branching form in the image is Cuffeyella arachnoidea, an encrusting cyclostome bryozoan well represented in the Cincinnatian Group (Taylor and Wilson, 1996). The conical encrusters are the lophophorate Cornulites flexuosus, a species we covered earlier in detail.

These sclerobionts were well protected from weathering on the outcrop by the concavity of the brachiopod’s interior, giving us a beautiful vignette of an ancient ecosystem.


Conrad, T.A. 1842. Observations on the Silurian and Devonian Systems of the United States, with descriptions of new organic remains. Journal of the Academy of Natural Sciences of Philadelphia 8: 228-280.

Hall, J. 1847. Paleontology of New York, v. 1: Albany, State of New York, 338 p.

Taylor, P.D. and Wilson, M.A. 1996. Cuffeyella, a new bryozoan genus from the Late Ordovician of North America, and its bearing on the origin of the post-Paleozoic cyclostomates, p. 351-360. In: Gordon, D.P., A.M. Smith and J.A. Grant-Mackie (eds.), Bryozoans in Space and Time. Proceedings of the 10th International Bryozoology Conference, Wellington, New Zealand, 1995. National Institute of Water & Atmospheric Research Ltd, Wellington, 442 pages.

Paleontology field trip in southeastern Indiana

September 9th, 2012

RICHMOND, INDIANA–Geology students in the Cincinnati area are a bit spoiled when it comes to finding fossils in the field. The Upper Ordovician rocks here are world-famous for the extraordinary abundance, variety and preservation of invertebrate fossils.like those shown above and below.

Today Wooster’s Invertebrate Paleontology class had its annual field trip to collect specimens for lab projects and analyses. We traveled to roadcut outcrops south of Richmond, Indiana — places Wooster Geologists have been visiting for about 30 years. Most recently Kit Price (’13) and her team was here collecting specimens for her Independent Study project. She was on this trip as well, and the class found lots of goodies for her work.

Our fleet of vehicles at our first outcrop (the Whitewater Formation).

Matt Peppers (’13) and Will Cary (’13) striking a Team Utah pose with the Whitewater Formation. Note that this rock unit is mostly resistant limestone beds.

The outcrop of the Liberty Formation at our second stop. (The Liberty is known as the Dillsboro Formation in Indiana, but we tend to use the Ohio names just across the border.) Note the prominence of less resistant shale.

It was a great day — sunny, warm and full of fossils. This class was especially adept at finding unusual specimens, several of which will show up us Fossils of the Week!

Wooster’s Fossil of the Week: a bifoliate bryozoan (Upper Ordovician of Indiana, USA)

August 12th, 2012

The specimen above is a species within the trepostome bryozoan genus Peronopora Nicholson, 1881. I don’t know which species because that would require me to slice it open and examine its microscopic skeletal details. (A reason why trepostome bryozoans are not especially popular among fossil collectors!) I found it on a recent field trip to the Whitewater Formation (Upper Ordovician, about 450 million years old) in eastern Indiana for Kit Price’s Independent Study project. Below is a photograph of the outcrop taken by Katherine Marenco (’03) — the most dramatic perspective I’ve seen for that simple roadcut!
Peronopora is bifoliate, meaning that it grew erect and budded on two sides from a central plane. Its skeleton was made of thick calcite, so it was resistant on the Ordovician seafloor during life and after death. As you can see in the close-up image below, the surface of this bryozoan is complex. It had other thin bryozoans growing on it (mainly Cuffeyella), and it was bored by worm-like organisms before and after death.

The genus Peronopora is one of the best studied trepostome bryozoans because of its thick, well preserved skeleton and abundance from the Middle through the Upper Ordovician. (Our specimen is in the Richmondian Stage and so is one of the last of its kind.) Paleontologists listed below in the references have examined in detail the colony growth (astogeny), paleoenvironments, biogeography and stratigraphic occurrences of Peronopora, making it a model for the order. My colleague Tim Palmer and I collected the genus to find beautiful examples of the bioclaustration Catellocaula vallata.

Peronopora was described in 1881 by Henry Alleyne Nicholson (1844-1899), an English paleontologist we’ve seen previously in this blog. The genus has a complicated early taxonomic history, having at one point been considered a kind of sponge.


Anstey, R.L. and Pachut, J.F. 2004. Cladistic and phenetic recognition of species in the Ordovician bryozoan genus Peronopora. Journal of Paleontology 78: 651-674.

Boardman, R.S. and Utgaard, J. 1966. A revision of the Ordovician bryozoan genera Monticulipora, Peronopora, Heterotrypa, and Dekayia. Journal of Paleontology 40: 1082-1108.

Hickey, D.R. 1988. Bryozoan astogeny and evolutionary novelties: Their role in the origin and systematics of the Ordovician monticuliporid trepostome genus Peronopora. Journal of Paleontology 62: 180-203.

Nicholson, H.A. 1881. On the structure and affinities of the genus Monticulipora and its subgenera. William Blackwood and Sons, Edinburgh, 235 p.

Pachut, J.F. and Anstey, R.L. 2009. Inferring evolutionary modes in a fossil lineage (Bryozoa: Peronopora) from the Middle and Late Ordovician. Paleobiology 35: 209-230.

Wooster Geologists in Indiana!

July 28th, 2012

WOOSTER, OHIO–I’ve seen a lot of fossils in my blessedly long time as a paleontologist, and I’ve had the opportunity to study them in many exotic places. I’m often reminded, though, that one of the best preserved and most diverse fossil faunas is in my backyard: the Cincinnati Region. The fossils here from the Upper Ordovician are extraordinary, and they will always be a resource for paleontological research. They’re just plain fun to find, too. There is a reason why so many American paleontologists have educational roots in the Ohio, Kentucky and Indiana area.

Sure, the setting is not always glorious. Instead of castles in the distance, we are often working in roadside ditches, but the fossils are so fascinating that we forget the prosaic American recreational weekend traffic zooming by to local parks, lakes and rivers. In the above image you see Katherine Marenco (’03), Richa Ekka (’13) and Kit Price (’13) today on our first outcrop of the in eastern Indiana just south of Richmond (C/W-148 in our locality system). It is an outcrop of the Whitewater Formation (Richmondian, Upper Ordovician) known by many Wooster geologists from paleontology course field trips to Indiana. It is chock-jammy-full of fossils, as you can see from the random shot below:

We are here today to collect material for Kit Price’s Junior (and then Senior) Independent Study project. She will be studying bioimmuration processes in these rocks. We will have more on her study after we unpack and clean the treasures we collected today.

Accompanying us on this field trip is Dr. Katherine Nicholson Marenco (Wooster ’03), shown above. She is visiting to Wooster to renew work on Jurassic bioimmuration and aragonite dissolution in the Portlandian of southern England, the topic of her Senior Independent Study in 2002-2003. She went on to graduate school and a post-doc position and is now at Bryn Mawr in Pennsylvania. We are very fortunate to have her with us because of her expertise on the topic of “upside-down encrusters” and her many creative ideas. We look forward to much collaboration! (You can see her in this old page on Paleontology at Wooster.)

Richa Ekka (above) generously volunteered to help us find and collect fossils. You may remember Richa from her very recent work in Estonia. (It is difficult to believe that just two weeks ago we were on islands in the Baltic.) Richa, as always, found great specimens.

Here is Kit working on our last Cincinnatian outcrop near Brookville, Indiana (C/W-111). Note the very dry grass, a result of the continuing drought in this part of the state. The temperatures today, by the way, were in the pleasant high 60s and low 70s.

Finally, we just had to share a photograph of our rented field vehicle: a Dodge Avenger. We think this is the trendiest car color of 2012: burnt pumpkin.

More in later posts on what we found on this field trip, and Kit’s developing Independent Study project. It was a spectacular field day with excellent fossils and great conversations.

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