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!

Upside-down and inside-out: Cryptic skeletobiont communities from the Late Ordovician of Ohio, Indiana, and Kentucky — An abstract submitted to the Geological Society of America for the 2012 annual meeting

August 14th, 2012

Editor’s note: The Wooster Geologists in Indiana this summer wrote an abstract for the Geological Society of America Annual Meeting in Charlotte, North Carolina, this November. The following is from student guest blogger Kit Price in the format required for GSA abstracts:

Upside-down and inside-out: Cryptic skeletobiont communities from the Late Ordovician of Ohio, Indiana, and Kentucky

PRICE, Katherine W. and WILSON, Mark A., Department of Geology, The College of Wooster, 944 College Mall, Wooster, OH 44691

In the majority of the studies in which skeletobiont communities are described, they are found on the exteriors of shell substrates. Skeletobiont communities that inhabited cryptic environments inside some of these same organisms are poorly known. In those instances where cryptic skeletobiont communities have been described, they are on a much larger scale (i.e., cavities in bryozoan reefs and under hardground ledges) and do not include smaller cryptic communities. The Cincinnatian Series of Ohio, Indiana, and Kentucky has many examples of these cryptic communities. Skeletobionts encrusted the interiors of gastropod, monoplacophoran, and nautiloid shells post-mortem, and are mostly made up of sheet and runner-type bryozoans and cornulitids, along with some craniid brachiopods and microconchids. Interestingly, in contrast to other studies on skeletobionts, the majority of the encrusters in our study do not appear to have been concerned with the location of the host aperture. Only the runner-type bryozoans (Cuffeyella and Corynotrypa) appear to have some directional preference, generally increasing their crypticity and branching away from the aperture. However, increasing crypticity is not always the case; sometimes the bryozoans branch parallel to the aperture or even grew towards it. Aside from shedding light on the life habits of these encrusters, these cryptic skeletobionts also inadvertently preserved their hosts through bioimmuration. Bioimmuration is a type of fossil preservation in which a skeletal organism overgrows another, preserving its negative relief. These cryptic communities not only tell us more about the organisms living in these isolated cavities, but they also have preserved detailed external and internal molds of their host aragonitic fauna. This provides information about shell morphology that would have otherwise been lost to dissolution. Because of the abundance of skeletal bioimmuration in the Cincinnatian, a comparison of cryptic to exposed skeletobionts living in the same environments can be made.


The header photograph is of an internal mold of a monoplacophoran mollusk. At the left you can see the branching runners of the bryozoan Cuffeyella, shown in closer view below.

Above is a close-up of the monoplacophoran internal mold. This bryozoan (Cuffeyella) was growing on the inside of the monoplacophoran shell. That shell filled with sediment and then dissolved, leaving the cemented sediment and the underside of the encrusting bryozoan. (Thus the “upside-down and inside-out” preservation.)

This is a view of the underside of skeletobionts that grew inside a nautiloid conch. The conch dissolved, leaving the undersides of various encrusters. A = the inarticulate brachiopod Petrocrania; B = sheet-like bryozoan; C = a rare microconchid with an extended apertural tube; D = another sheet-like bryozoan; E = one of many Trypanites or Palaeosabella borings.

Kit Price (’13) on one of her outcrops in Indiana (C/W-149) on July 28, 2012.

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.

Wooster’s Fossil of the Week: a trilobite burrow (Upper Ordovician of Ohio)

May 27th, 2012

This is one of my favorite trace fossils. Rusophycus pudicum Hall, 1852, is its formal name. It was made by a trilobite digging down into the seafloor sediment back during the Ordovician Period in what is now southern Ohio. It may have been hiding from a passing predator (maybe a eurypterid!), just taking a “rest” (what I learned in college), or maybe looking for worms to eat. (There is another example on this blog from the Cambrian of western Canada.)

Rusophycus is always the first trace fossil I introduce in the Invertebrate Paleontology course because it is simple in form and complex in interpretation. It shows that a relatively straightforward process (digging down with its two rows of legs) can have had several motivations. Rusophycus even shows that more than one kind of organism can make the same type of trace. Rusophycus is also found in the Triassic, long after trilobites went extinct. (These were likely made by horseshoe crabs.) It is also good for explaining the preservation of trace fossils. The specimen above is “convex hyporelief”, meaning it is on the bottom of the sedimentary bed and convex (sticking out rather than in). This is thus sediment that filled the open trilobite excavation.

Trilobites making Rusophycus (from http://www.geodz.com/deu/d/Trilobita).

James Hall (1811–1898) named Rusophycus pudicum in 1852. The image of him above is from shortly before his death (photograph credit: The American Monthly Review of Reviews, v. 18, 1898, by Albert Shaw). He was a legendary geologist, and the most prominent paleontologist of his time. He became the first state paleontologist of New York in 1841, and in 1893 he was appointed the New York state geologist. His most impressive legacy is the large number of fossil taxa he named and described, most in his Palaeontology of New York series.

James Hall is in my academic heritage. His advisor was Amos Eaton (1776-1842), a self-educated geologist (he learned it by reading in prison!). One of James Hall’s students was Charles Schuchert (1856-1942), a prominent invertebrate paleontologist. Schuchert had a student named Carl Owen Dunbar (1891-1979) — Schuchert and Dunbar were coauthors of a famous geology textbook. Dunbar had a student at Yale named William B.N. Berry (1931-2011), my doctoral advisor. Thus I feel an intellectual link to old man Hall above.


Baldwin, C.T. 1977. Rusophycus morgati: an asaphid produced trace fossil from the Cambro-Ordovician of Brittany and Northwest Spain. Palaeontology 51: 411–425.

Donovan, S.K. 2010. Cruziana and Rusophycus: trace fossils produced by trilobites … in some cases? Lethaia 43: 283–284.

Hall, J., Simpson, G.B. and Clarke, J.M. 1852. Palaeontology of New York: Organic remains of the Lower Middle Division of the New-York System. C. Van Benthuysen, New York, 792 pages.

Wooster’s Fossil of the Week: the classic bioclaustration (Upper Ordovician of Ohio)

April 29th, 2012

We’re looking at two fossils above. One is the bryozoan Peronopora, the major skeletal structure. The second is the odd series of scalloped holes in its surface. These are a trace fossil called Catellocaula vallata Palmer and Wilson 1988. They at first appear to be borings cut into the bryozoan colony. Instead they are holes formed by the intergrowth of a soft-bodied parasite with the living bryozoan colony. This type of trace fossil is called a bioclaustration. We gave it the Latin name for “little chain of walled pits”.

My good friend Tim Palmer and I found this specimen and many others in 1987 as we explored the Upper Ordovician Kope Formation in the Cincinnati region. We were collecting bioeroded substrates like hardgrounds and shells, and these features were clearly different from the usual borings. They do not actually cut the bryozoan skeleton, for one thing. For another it is apparent that the bryozoan growth was deflected around whatever sat in those spaces. Tim and I called this kind of interaction “bioclaustration”, meaning “biologically walled -up”.
Catellocaula vallata on the Upper Ordovician bryozoan Amplexopora. Note that the scalloped holes have more lobes than those seen in the lead image. This may mean it was a different species of infesting soft-bodied organism.

The infesting parasite on the bryozoan colony was itself colonial, consisting of small clusters connected by extended stolons. The bryozoan grew around the parasite, roofing over the stolons and making walls on the margins of the clusters. We think the parasite was a soft-bodied ascidian tunicate like the modern Botryllus. If true, it is the earliest fossil tunicate known.

This closer view of C. vallata shows the scalloped margins of the pits and the horizontal connections between them.

Another specimen of C. vallata. This view shows the flat floors of the bioclaustration features.

Acetate peels cut longitudinally through the bryozoan and bioclaustrations. On the left you can see that the bryozoan zooecia (long tubes) were deflected sideways as they grew. On the right is a tunnel connecting two pits, with bryozoan zooids forming the roof. (From Palmer and Wilson, 1988.)


Bromley, R.G., Beuck, L. and Taddei Ruggiero, E. 2008. Endolithic sponge versus terebratulid brachiopod, Pleistocene, Italy: accidental symbiosis, bioclaustration and deformity. Current Developments in Bioerosion, Erlangen Earth Conference Series, 2008, III, 361-368.

Palmer, T.J. and Wilson, M.A. 1988. Parasitism of Ordovician bryozoans and the origin of pseudoborings. Palaeontology 31: 939-949.

Tapanila, L. 2006. Macroborings and bioclaustrations in a Late Devonian reef above the Alamo Impact Breccia, Nevada, USA. Ichnos 13: 129-134.

Taylor, P.D. and Voigt, E. 2006. Symbiont bioclaustrations in Cretaceous cyclostome bryozoans. Courier Forschungsinstitut Senckenberg 257: 131-136.

Wooster’s Fossil of the Week: an encrusted nautiloid (Upper Ordovician of Kentucky)

March 4th, 2012

Two fossils this week in our series. The large segmented cone is a bisected nautiloid cephalopod from the Upper Ordovician of northern Kentucky. The original shell (made of the mineral aragonite) has been dissolved away, leaving the sediment that filled it (making an internal mold). Encrusting the nautiloid mold is a grayish, bumpy layer called Dermatostroma Parks, 1910.

The nautiloid belongs to a subclass of cephalopods still with us today. This Ordovician fossil is in the Family Orthoceratidae McCoy, 1844, which existed from the Early Ordovician (490 million years ago) through the Triassic (230 million years ago). It had a straight, conical shell with walls inside separating chambers (camerae) and a central tube (the siphuncle) connecting them. They were swimming (nektic) predators that could control their buoyancy through a mix of gases and liquids in the camerae mediated by the siphuncle.
Reconstruction of an orthocerid nautiloid by Nobu Tamura.

The fact that the mold is encrusted is interesting in itself. The encrusting organism (Dermatostroma) had to grow over the mold after the aragonitic shell had dissolved and the sediment cemented up. This must have happened on the seafloor, not long after the death and partial burial of the nautiloid. Such rapid dissolution and cementation is characteristic of Calcite Sea conditions, a situation we don’t have in today’s oceans.

Dermatostroma is a genus of stromatoporoid sponge named and described by William Arthur Parks in 1910. It is always very thin and often distinguished by a field of tiny bumps (meaning this species is likely Dermatostroma papillatum). It was a filter-feeding organism, and its fossils are often overlooked.

William Arthur Parks (1868-1936) was a Canadian paleontologist from Hamilton, Ontario. He was a professor at the University of Toronto for most of his career. In 1927, he was elected President of the Paleontological Society. Parks did detailed work on the almost microscopic details of fossil stromatoporoid sponges, and then made a dramatic field change and became an accomplished dinosaur paleontologist. The small ornithopod dinosaur Parksosaurus is named after him.


Palmer, T.J., Hudson, J.D. and Wilson, M.A. 1988. Palaeoecological evidence for early aragonite dissolution in ancient calcite seas. Nature 335 (6193): 809–810.

Parks, W.A. 1910. Ordovician stromatoporoids of America. University of Toronto Studies, Geology Series 7, 52 pp.

Sweet, W.C. 1964. Nautiloidea — Orthocerida, in Treatise on Invertebrate Paleontology. Part K. Mollusca 3, Geological Society of America, and University of Kansas Press, New York, New York and Lawrence, Kansas.

Wooster’s Fossil of the Week: A mysterious sponge (Late Ordovician of Ohio)

February 5th, 2012

I’ve been collecting and studying fossils from the Upper Ordovician of the Cincinnati region for three decades now, but I’ve never seen another specimen like the one pictured above. An amateur collector, Howard Freeland, generously donated this rock to Wooster late last year. He found it in Cincinnatian limestones cropping out in Brown County, Ohio.

At first Howard understandably thought he had found fish bones, which would be extraordinary for this age of rock and place of deposition. He took the slab to the Smithsonian Institution for identification by a vertebrate paleontologist. Not bones, was the answer, but they didn’t know how else to classify these finger-like fossils. When Howard showed them to me I suggested they were fossil sponges, and so here we are. I could be wrong so I hope the web community has some other ideas.

I believe these are sponge pieces because they were originally hollow (now they are filled with sediment), fibrous in structure, and had small holes irregularly preserved on their surfaces. They look in texture like the hexactinellid sponge Brachiospongia, but they do not have their distinctive thick extensions and radiating shape.

Small, irregular holes on fossil surface. They could be sponge incurrent pores. I would expect them to be more regular, though.

My search of the Ordovician sponge literature (what there is of it) has not turned up anything similar. I’ve gone to the usual websites for the Cincinnatian (like Steve Holland’s excellent Cincinnatian fossil catalog and the Dry Dredger’s webpages), but no luck.

Sometime during the existence of this webpage someone will come across these images and post their solution in the comments. I look forward to learning from them!


Carrera, M.G. and Rigby, J.K. 1999. Biogeography of Ordovician sponges. Journal of Paleontology 73: 26-37.

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