Wooster’s Fossils of the Week: A trilobite hypostome with an encrusting cyclostome bryozoan (Upper Ordovician of Kentucky)

May 26th, 2017

A quick post this week. Above is a bit of a large isotelid trilobite my students and I found this past spring break on an expedition to the Upper Ordovician (Katian) of northern Kentucky. It was collected at a roadside outcrop of the Corryville Formation (Location C/W-740). It doesn’t look like the usual trilobite bit because it is a less common fragment from the underside of the cephalon known as the hypostome (meaning “under mouth”). Note on the left side of the image some branching white encrustations, shown closer below.

These are encrusting cyclostome bryozoans known as Cuffeyella arachnoidea. The genus Cuffeyella was named in 1996 by two characters you know from this blog: Taylor & Wilson. As you can see, these particular specimens are in terrible shape. We have far better images of well-preserved Cuffeyella elsewhere on this blog. One of the lessons of a paleontological education, though, is to learn how to recognize fossils when they are not at their best.

Wooster’s Fossil of the Week is now going to take a hiatus as the summer research and travel season begins. It will return later!

Reference:

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.

Wooster’s Fossils of the Week: A slab of Upper Ordovician bivalves from northern Kentucky

March 31st, 2017

Earlier this month, Luke Kosowatz, Matt Shearer and I went on a field trip through the Cincinnati region collecting Upper Ordovician (Katian) bryozoans and examples of bioerosion for their Independent Study projects and other investigations. I picked up the above slab and put it in our vehicle for future study not because of its beauty, but the preservational modes it displays. The black, rounded objects are bivalves, probably of the Order Modiomorphida. They are miserable fossils to identify because they originally had shells made of the mineral aragonite, which dissolved quickly after the animals died. What is left are a few scrappy molds and that black film. This is a common preservation of bivalves in the Cincinnatian.

This is the Corryville Formation outcrop from which the slab came. It is just west of Maysville, Kentucky, along the AA Highway (N 38.60750°, W 83.76775°; C/W-740).

Here is the slab along the roadside before we cleaned it up. Not much to see, really, except the low-relief black blobs that are remains of bivalves.

As you see, not much detail in the bivalves other than an outline matching somewhat the modiomorphids. Those of you with sharp paleontological eyes will note a round gray patch with radiating lines. This is a bryozoan that was attached to the bivalve shell. When the shell dissolved, the bryozoan attachment surface became visible. In other words, this is an upside-down encrusting bryozoan, a condition we’ve seen several times in this blog.

Here’s another bivalve with an upside-down encrusting bryozoan. This time you can see that the black film was underneath the bryozoan and on the outside of the bivalve shell. In a 2004 paper, Tim Palmer and I wrote: “We have also long been curious about why some of the epifaunal aragonitic Ordovician genera in the Cincinnatian such as Modiolopsis are preserved with a thick black outer shell covering (e.g. Pojeta 1971, pl. 15, fig. 6). It now seems likely that this was a hypertrophied periostracum that conferred some protection against dissolution during life, similar to the situation seen in Recent unionids that are susceptible to dissolution in their fresh-water habitats” (p. 425). Maybe it’s time we followed up on these speculations? I’m sure other paleontologists have had similar ideas.

Among the indistinct modiomorphid bivalves is this old friend: Ambonychia with its characteristic radiating ridges.

References:

Palmer, T.J. and Wilson, M.A. 2004. Calcite precipitation and dissolution of biogenic aragonite in shallow Ordovician calcite seas. Lethaia 37: 417-427.
Pojeta, J. 1971. Review of Ordovician pelecypods. United States Geological Survey, Professional Paper 695, 1-46.

Wooster’s Fossil of the Week: A large trepostome bryozoan on a nautiloid conch (Upper Ordovician of northern Kentucky)

March 17th, 2017

This massive trepostome bryozoan, a solid lump of biogenic calcite, was collected earlier this week on the latest Team Cincinnati field expedition into the treasure-filled Upper Ordovician underlying and surrounding that city. Wooster students Matt Shearer, Luke Kosowatz and I are pursuing projects related to trepostome bryozoans and bioerosion (the biological destruction of hard substrates). The above specimen combines both these worlds, and more. Note the concavity at the base of the specimen. It comes from the Bellevue Formation (Katian) exposed on Bullitsville Road near the infamous Creation Museum (C/W-152).

Underneath the bryozoan colony (its zoarium) is this conical impression. It is an external mold of a straight nautiloid conch, the shell of a common squid-like cephalopod during the Ordovician. After the death of the nautiloid its empty tubular conch rested on the seafloor. This hard surface attracted the larvae of a variety of bryozoans that spread their calcitic zoaria (colonial skeletons) across the surface. Eventually one trepostome bryozoan species gained dominance over the space and occupied it all, growing into the large colony we see today. It even wrapped around the aperture of the conch (on the left) and grew a bit into the tube. Since the nautiloid conch was made of unstable aragonite, it long ago dissolved away, leaving an impression (external mold) in the stable calcite of the bryozoan.

How do we know there were earlier generations of bryozoans on this conch? We see them exposed upside-down on the surface of the external mold. Above we see the thin, branching cyclostome bryozoan Cuffeyella in the foreground, with a sheet of an encrusting trepostome bryozoan in the background. There are several other earlier bryozoans visible on this surface, revealing an ecological succession. There may be soft-bodied organisms preserved on this surface as well. This locality yielded the first described specimens of bioimmuration in the Ordovician (see Wilson et al., 1994).

There were other large trepostome bryozoans found in this same locality. I couldn’t resist cutting one in half to see what the inside looked like.

In this close view of the cross-section through the calcitic trepostome bryozoan we see numerous round holes drilled by some sort of worm seeking protective space so it could filter-feed. (In other words, it was not preying on the bryozoan.) The most intense boring of the specimen appears to have taken place just before and after the death of the colony. We know some borings were excavated into living bryozoan skeleton because the bryozoan formed reactive tissue around the intruder. The very tiny reddish-brown dots scattered in layers are “brown bodies“, the organic remnants of bryozoan polypides in their skeletal tubes (zooecia).

It has been a pleasure to return to the extraordinary Cincinnati fossils!

References:

Taylor, P.D. 1990. Preservation of soft-bodied and other organisms by bioimmuration—a review. Palaeontology 33: 1-17.

Wilson, M.A. 1985. Disturbance and ecologic succession in an Upper Ordovician cobble-dwelling hardground fauna. Science 228: 575-577.

Wilson, M.A., Palmer, T.J. and Taylor, P.D. 1994. Earliest preservation of soft-bodied fossils by epibiont bioimmuration: Upper Ordovician of Kentucky. Lethaia 27: 269-270.

Team Cincinnati moves into Kentucky for additional fieldwork

March 12th, 2017

Maysville, Kentucky — It was another frigid morning under the clear, pitiless skies of the Cincinnati region, but Luke Kosowatz (’17) was in good spirits. He is collecting at our first stop of the day: an exposure of the Bellevue Formation (Upper Ordovician, Katian) along the Bullitsville Road in northern Kentucky (N 39.08121°, W 84.79230°; C/W-152). Luke is sorting out bioeroded bryozoans and brachiopods here.

Matt Shearer (’18) joins Luke on the outcrop. If the place looks familiar it’s because William Harrison (’15) and I were here almost exactly three years ago.

In cosmic irony, the Bullitsville outcrop is nearly a neighbor of the Creation Museum. It was closed this Sunday morning — who would have guessed? Do Creationists ponder the fact that their pseudoscientific establishment sits on an incredible record of fossils 450 million years old? They do indeed: “These conditions and processes would be expected during the global catastrophic Flood described in the Scriptures. The thin alternating coarse-grained limestone and fine-grained shale layers could be deposited quickly under such catastrophic conditions.” Of course.

We were also near Big Bone Lick State Park, the birthplace of American vertebrate paleontology.

This site has an excellent life-sized diorama of Late Pleistocene animals (mammoths, mastodons, bison, ground sloths and even vultures) getting mired in bogs infused with salty water.

Team Cincinnati then traveled east for about an hour to the magnificent exposures of the Cincinnatian Group around Maysville, Kentucky. Here we targeted the Corryville Formation exposed along the AA Highway (N 38.60750°, W 83.76775°).

As with all our sites, the fossils are extraordinary. This is an ordinary slab of limestone from the Corryville with dozens of well-preserved strophomenid brachiopods.

For nostalgia on my part, we visited an outcrop along US 62 at the southern edge of Maysville where the Corryville Formation is again exposed (N 38.60932°, W 83.81070°). It is at this site that I collected a cave-dwelling bryozoan fauna now the subject of a manuscript Caroline Buttler (National Museum Wales) and I are finishing up this month. The cave interval was destroyed by later roadwork, but the remaining outcrops were superb for our purposes.

We ended the field day about seven kilometers north at another outcrop of the Corryville along US 62 (N 38.6445°, W 83.77678°).  I was so distracted by the diversity of fossils that I forgot to take pictures!

Dinner was at El Caminante Mexican Restaurant in Maysville. It was so good we are compelled to recommend it to future geological visitors.

Wooster’s Fossils of the Week: An Upper Ordovician cave-dwelling bryozoan fauna and its exposed equivalents

July 3rd, 2015

1 Downwards 063015This week’s fossils were the subject of a presentation at the 2015 Larwood Symposium of the International Bryozoology Association in Thurso, Scotland, last month. Caroline Buttler, Head of Palaeontology at the National Museum Wales, Cardiff, brilliantly gave our talk describing cryptic-and-exposed trepostome bryozoans and their friends in an Upper Ordovician assemblage I found years ago in northern Kentucky. They were the subject of an earlier Fossil of the Week post, but Caroline did so much fine work with new thin sections and ideas that they deserve another shot at glory. We are now working on a paper about these bryozoans and their borings. Below you will find the abstract of the talk and a few key slides to tell the story.

__________________________________

Trepostome bryozoans have been found as part of an ancient cave fauna in rocks of the Upper Ordovician (Caradoc) Corryville Formation exposed near Washington, Mason County, Kentucky.

Bryozoans are recognized as growing from the ceiling of the cave and also from an exposed hardground surface above the cave. Multiple colonies are found overgrowing one another and the majority are identified as Stigmatella personata. Differences between those growing upwards and those growing down from the roof have been detected in the limited samples.

The colonies have been extensively bored, these borings are straight and cylindrical. They are identified as Trypanites and two types are recognised. A smaller variety is confined within one colony overgrowth and infilled with micrite. In thin section it is observed that the borings follow the lines of autozooecial walls and do not cut across. This creates a polygonal sided boring, suggesting that the colonies were not filled with calcite at the time of the boring. The second variety has a larger tube size and its infilling sediment has numerous dolomite rhombs and some larger fossil fragments including cryptostomes, shell and echinoderm pieces. These cut through several layers of overgrowing bryozoans. Some of the borings contain cylindrical tubes of calcite similar to the ‘ghosts’ of organic material described by Wyse Jackson & Key (2007).

Very localised changes in direction of colony growth due to an environmental effect are seen.

Bioclaustration in these samples provides evidence for fouling of the colony surface, indicating that the bryozoans overgrew unknown soft-bodied organisms.

Reference:

Wyse Jackson, P. N., and M. M. Key, Jr. (2007). Borings in trepostome bryozoans from the Ordovician of Estonia: two ichnogenera produced by a single maker, a case of host morphology control. Lethaia. 40: 237-252.

2 Title 0630153 Location 0630154 Strat position 0630155 hdgd up 0630156 hdgd down 0630157 Growth up 0630158 Growth down 0630159 Stigmatella 06301510 Cartoon 06301511 Boring A 06301512 Boring B 06301513 Ghosts explanation14 Ghosts 06301515 Overgrowths 06301516 Further questions 063015

Wooster’s Fossils of the Week: A pair of molded nautiloids from the Upper Ordovician of northern Kentucky

October 24th, 2014

1 Nautiloid pair 091314Two nautiloids are preserved in the above image of a slab from the Upper Ordovician of northern Kentucky. (I wish I knew which specific locality. This is why paleontologists are such fanatics about labeling specimens.) The top internal mold (meaning it is sediment that infilled a shell now dissolved away) has been covered in a previous blog entry. This week I want to concentrate on the nautiloid at the bottom.

These nautiloids belong to the Family Orthoceratidae McCoy, 1844, which existed from the Early Ordovician (490 million years ago) through the Triassic (230 million years ago). They had conical, aragonitic shells 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.

What is most interesting here is the preservation of these nautiloids. The aragonitic shells were dissolved away at about the same time the internal sediment was cemented, forming the internal molds. These molds were exposed on the seafloor, attracting encrusting organisms. This means the dissolution and cementation took place quickly and in the marine environment, not after burial. This rapid dissolving of aragonite and cementation by calcite is typical of Calcite Sea geochemistry, something we don’t see in today’s Aragonite Seas.
2 Nautiloid siphuncle 091314Above is a close view of the cemented siphuncle of the lower nautiloid, heavily encrusted by a trepostome bryozoan.
3 Bryozoan undersideEven more cool, the outside of the lower nautiloid was encrusted by several trepostome bryozoan colonies. When the shell dissolved it left the undersides of these bryozoans exposed, as seen above. These undersides often contain the remains of shelly organisms the bryozoans encrusted (see the Independent Study project by Kit Price ’13) and even soft-bodied animals (epibiont bioimmuration; see Wilson et al., 1994).

A neat package here resulting from biological, sedimentological and geochemical factors.

References:

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.

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.

Wilson, M.A., Palmer, T.J. and Taylor, P.D. 1994. Earliest preservation of soft-bodied fossils by epibiont bioimmuration: Upper Ordovician of Kentucky. Lethaia 27: 269-270.

Wooster’s Fossils of the Week: A nest of cornulitid tubeworms and friends from the Upper Ordovician of northern Kentucky

September 19th, 2014

Cornulitids and bryozoan Bellevue 585This fascinating and complicated little cluster of cornulitid wormtubes was found by my current Independent Study student William Harrison while we were doing fieldwork near Petersburg, Kentucky. (Just down the road from the infamous Creation Museum, ironically.) It was collected from a roadcut in the Bellevue Member of the Grant Lake Formation (Upper Ordovician, locality C/W-152). We’ve seen all the elements before (cornulitids, bryozoans and stromatoporoids), but not in such a tight set of relationships. I find this aspect of paleontology to be one of the most delightful: who lived with whom and how?
reconstr1The tubes are of the common Paleozoic genus Cornulites Schlotheim 1820, and the species is Cornulites flexuosus (Hall 1847). These long-extinct little marine animals had calcitic shells and likely bore a filter-feeding lophophore, as shown in the reconstruction above by my friend Olev Vinn. They appear to be related to brachiopods, bryozoans, phoronids, and some other tubeworms that shared this feeding device and certain features of the shell. Their life goal was to keep their lophophore or equivalent apparatus free of obstructions so they could collect nutrients from the surrounding seawater.
cornulitid whole specimen 091214The bryozoan, which makes up the primary substrate of the specimen (seen above) is a trepostome. Its skeleton contains hundreds of tiny tubes (zooecia) that held individuals (zooids) in the colony (zoarium — these terms are for my paleo students this week!). Each zooid in this type of bryozoan had a lophophore for filter-feeding.
cornulitid, dermatostroma, bryozoanAbove we see a thin, light-colored, bumpy sheet in the center of the image covering three of the cornulitid tubes and some of the bryozoan. This is the stromatoproid Dermatostroma papillatum (James, 1878). Stromatoporoids were a kind of sponge with a skeletal base, so this organism was also a filter-feeder. (It was originally known as Stromatopora papillata James, 1878.) Here we see the interesting symbioses (living together) aspects of this tiny assemblage. In the top right you see a cornulitid tube growing over the bryozoan, but the bryozoan in turn is overgrowing its proximal parts. The bryozoan and the cornulitid were thus alive at the same time. The stromatoporoid is growing over the bryozoan and the three cornulitids, but it is overgrown by cornulitids on the left. In addition, the stromatoporoid did not obstruct the cornulitid apertures, an indication that they were occupying living tubeworms. My hypothesis, then, is that all three of these characters were alive at the same time growing in response to each other.

It could be that this represents a tiny hard substrate tiered assemblage, meaning that the organisms were selecting food resources at slightly different heights and particle sizes (see Ausich and Bottjer, 1982, for a start on the tiering literature). The cornulitids may have taken the largest bits, the bryozoans the next size, and then the stromatoporoids, as minuscule sponges, got the finest particles. This is another paleontological hypothesis that can be tested with further specimens.

It is also an example of the value of getting sharp-eyed students on the outcrops as often as possible. Good work, William!

References:

Ausich, W.I. and Bottjer, D.J. 1982. Tiering in suspension feeding communities on soft substrata throughout the Phanerozoic. Science 216: 173-174.

Galloway, J.J. and St. Jean, J., Jr. 1961. Ordovician Stromatoporoidea of North America. Bulletins of American Paleontology 43: 1-102.

Morris, W. R. and H. B. Rollins. 1971. The distribution and paleoecological interpretation of Cornulites in the Waynesville Formation (Upper Ordovician) of southern Ohio. The Ohio Journal of Science 71: 159-170.

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

Schlotheim, E.F. von. 1820. Die Petrefakten-Kunde auf ihrem jetzigen Standpunkte durch die Beshreibung seiner Sammlung versteinerter und fossiler Ueberreste des their-und Planzenreichs der Vorwelt erlaeutert. Gotha, 437 p.

Taylor, P.D., Vinn, O. and Wilson, M.A. 2010. Evolution of biomineralization in ‘lophophorates’. Special Papers in Palaeontology 84: 317-333.

Vinn, O. and Mutvei, H. 2005. Observations on the morphology and affinities of cornulitids from the Ordovician of Anticosti Island and the Silurian of Gotland. Journal of Paleontology 79: 726-737.

Wooster’s Fossils of the Week: An Ordovician hardground with a bryozoan and borings — and an unexpected twist

August 1st, 2014

1 Hardground Bryo Large 071514aThe view above, one quite familiar to me, is of a carbonate hardground from the Upper Ordovician Corryville Formation exposed near Washington, Mason County, Kentucky. We are looking directly at the bedding plane of this limestone. The lumpy, spotted fossil covering about half the surface is a trepostome bryozoan. It looks like a dollop of thick pudding plopped on the rock. In the upper left are round holes that are openings of the trace fossil Trypanites, a common boring in carbonate hard substrates.
2 Closer hdgd bryo 071514bThis closer view shows the bryozoan details in the right half. You can barely pick out the tiny pin holes of the zooecia (the tubes that contained the individual zooids) and see the raised areas called maculae, which may have assisted in directing water currents for these colonial filter-feeders. Without a thin-section or peel I can’t identify the bryozoan beyond trepostome. The Trypanites borings in the hardground surface are also visible.
3 Hardground oblique Ordovician sm 071514cThis oblique view brings all the elements together. The bryozoan has closely encrusted the microtopography of the hardground surface. The Trypanites borings are shown cutting directly through the limestone of the hardground. Both of these observations confirm that the hardground was cemented seafloor sediment when the encrusters and borers occupied it.
4 Cross section hdgd 071514dHere is a full cross-section view showing the borings and the draping nature of the bryozoan. Now for the twist — I’m showing the specimen upside-down! It was actually found in place with the bryozoan down, not up. This is the roof of a small cave on the Ordovician seafloor. The bryozoan was hanging down from the ceiling, and the boring organisms were drilling upwards. The true orientation of this specimen is thus —
5 Cross section hdgd right side up 071514dThe cave was apparently formed after the carbonate hardground was cemented on the seafloor. Currents may have washed away unconsolidated muds underneath the hardground, forming a small cavity then occupied by the borers and the bryozoan: an ancient cave fauna. Brett & Liddell (1978) showed similar cavity encrustation in the Middle Ordovician, and I recorded a nearly identical situation in the Middle Jurassic of Utah (Wilson, 1998). Other detailed fossil marine caves are described from the Jurassic by Palmer & Fürsich (1974) and Taylor & Palmer (1994).

I should write up this Ordovician story someday!

References:

Brett, C.E. and Liddell, W.D. 1978. Preservation and paleoecology of a Middle Ordovician hardground community. Paleobiology 4: 329– 348.

Bromley, R.G. 1972. On some ichnotaxa in hard substrates, with a redefinition of Trypanites Mägdefrau. Paläontologische Zeitschrift 46: 93–98.

Palmer, T.J. 1982. Cambrian to Cretaceous changes in hardground communities. Lethaia 15: 309–323.

Palmer, T.J. and Fürsich, F.T. 1974. The ecology of a Middle Jurassic hardground and crevice fauna. Palaeontology 17: 507–524.

Taylor, P.D. and Palmer, T.J. 1994. Submarine caves in a Jurassic reef (La Rochelle, France) and the evolution of cave biotas. Naturwissenschaften 81: 357-360.

Taylor, P.D. and Wilson. M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62: 1–103.

Wilson, M.A. 1998. Succession in a Jurassic marine cavity community and the evolution of cryptic marine faunas. Geology 26: 379-381.

Wilson, M.A. and Palmer, T.J. 1992. Hardgrounds and hardground faunas. University of Wales, Aberystwyth, Institute of Earth Studies Publications 9: 1–131.

Wooster’s Fossil of the Week: Intensely bored bryozoan from the Upper Ordovician of Kentucky

March 23rd, 2014

Bored Bryo 1 585Yes, yes, I’ve heard ALL the jokes about being bored, and even intensely bored. I learn to deal with it. This week we continue to highlight fossils collected during our productive expedition to the Upper Ordovician (Cincinnatian) of Indiana (with Coleman Fitch ’15) and Kentucky (with William Harrison ’15). Last week was Coleman’s turn; this week it is William’s.

The beautiful fan-like bifoliate (two-sided) trepostome bryozoan above was collected from the lower part of the Grant Lake Formation (“Bellevue Limestone”) at our locality C/W-152 along the Idlewild Bypass (KY-8) in Boone County, Kentucky (N 39.081120°, W 84.792434°). It is in the Maysvillian Stage and so below the Richmondian where Coleman is getting most of his specimens. I’ve labeled it to show: A, additional bryozoans encrusting this bryozoan; B, a very bored section; C, a less bored surface showing the original tiny zooecia, monticules, and a few larger borings.
Bored Bryo 2 585The other side of this bryozoan is more uniform. It has an even distribution of small borings and no encrusters. This likely means that at some point after the death of the bryozoan and subsequent bioerosion this side was placed down in the mud while the exposed opposite side was encrusted.
Encruster Bored Bryo 031314_585A closer view of the upwards-facing side (with the encrusting bryozoan at the top) shows just how intense the boring was prior to encrustation. Some of the borings are close to overlapping. The encrusting bryozoan has its own borings, but far fewer and significantly larger.
Close borings 031314_585In this close view of the downwards-facing side we see lots of the small borings. Some are star-shaped if they punched through the junction of multiple zooecia. Note that these borings are rather evenly spread and seem to have about the same external morphology and and erosion. Likely they were all produced about the same time. It must have been a crowded neighborhood when all those boring creatures were home.

The questions that are provoked by this specimen are: (1) Were there any borings produced while the host bryozoan was still alive? (We may find elements of bioclaustration with some holes); (2) Why are zones B and C in the top image so different in the amount of bioerosion? Could zone C have still been alive at the time and resisted most bioeroders? Maybe zone C was covered by sediment? (But the margin is very irregular); (3) Why are the later encrusting bryozoans (zone A) so much less bioeroded?; (4) How do we classify such tiny pits that are between microborings and macroborings in size? (Trypanites is becoming a very large category) (5) What kind of organism made so many small pits? Were they filter-feeders as we always say, or was something else going on? (Sectioning specimens like this may reveal some internal connections between the pits.)

William has plenty of fun work ahead of him!

References:

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

Bromley, R.G. 1972. On some ichnotaxa in hard substrates, with a redefinition of Trypanites Mägdefrau. Paläontologische Zeitschrift 46: 93–98.

Erickson, J.M. and Waugh, D.A. 2002. Colony morphologies and missed opportunities during the Cincinnatian (Late Ordovician) bryozoan radiation: examples from Heterotrypa frondosa and Monticulipora mammulata. Proceedings of the 12th International Conference of the International Bryozoology Association. Swets and Zeitlinger, Lisse; pp. 101-107..

Kobluk, D.R. and Nemcsok, S. 1982. The macroboring ichnofossil Trypanites in colonies of the Middle Ordovician bryozoan Prasopora: Population behaviour and reaction to environmental influences. Canadian Journal of Earth Sciences 19: 679-688.

Taylor, P.D. and Wilson. M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62 (1-2): 1–103.

Vogel, K. 1993. Bioeroders in fossil reefs. Facies 28: 109-113.

Wilson, M.A. and Palmer, T.J. 2006. Patterns and processes in the Ordovician Bioerosion Revolution. Ichnos 13: 109–112.

Ordovician bioclaustration project begins

March 10th, 2014

Bellevue outcrop 031014FLORENCE, KENTUCKY–Today it was William Harrison’s turn to collect specimens for his Independent Study project. He’ll be working a full year on what he’s putting in these bags before he turns in his thesis. William’s project is an interpretation of the processes that led to bioclaustration pits in Upper Ordovician bryozoans, along with larger questions of bioerosion of trepostome bryozoans. We found some gorgeous specimens at the outcrop above.

William is collecting from what used to be called the Bellevue Limestone, a Maysvillian unit between the Fairmount and Corryville Formations. Now it is best known as the lower part of the Grant Lake Formation. The rocks represent shallow water deposits, much like the Whitewater Formation Coleman was working in yesterday, so it is loaded with eroded and encrusted brachiopods and bryozoans. This is Locality C/W-152 in our system along the Idlewild Bypass (KY-8) in Boone County, Kentucky (N 39.081120°, W 84.792434°).

William 031014William was particularly adept at finding large bryozoan zoaria (colonies), most of which were riddled with borings. He is here holding a specimen that in life would have been erect on the sea floor like a fan with feeding zooids on each side. You may be able to make out the many little bumps or monticules on its surface.

Guess who our neighbor was during our exploration of this outcrop?

Creation Museum 031014Yes, the irony is deep. “Billions of dead things” indeed, Mr. Ham!

Later that day we collected a few bored and bioclaustrating bryozoans from an exposure of the Kope Formation at Orphanage Road to the east (N 39.02984°, W 84.54121°). We have plenty of specimens to keep both William and Coleman busy, and already some ideas for poster presentations.

Just to show the human effect of sampling and collecting, our first stop of the day was entirely unsuccessful. We visited one of my first localities, an exposure of the Kope Formation at the confluence of the Ohio River and Gunpowder Creek in Boone County, Kentucky (C/W-7; N 38.90428°, W 84.79779°). It was here in 1984 that my wife Gloria and I found hundreds of fantastic encrusted cobbles, many with gorgeous edrioasteroids and thick accumulations of bryozoans. These were for a very brief moment famous in the local collecting community. Within a few months they were all gone. William and I were there now 30 years later hoping a new cobble or two might have eroded out, but we found nothing. A future researcher would have no idea such cobbles were present, except for the one paper in the literature.

 

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