Wooster’s Fossils of the Week: Bioclaustration-boring structures in bryozoans from the Upper Ordovician of the Cincinnati region

February 9th, 2014

Chimneys 149aAnother bioerosion mystery from those fascinating Upper Ordovician rocks around Cincinnati. Above you see a flat, bifoliate trepostome bryozoan (probably Peronopora) with pock holes scattered across its surface. At first you may think, after reading so many blog posts here, that these are again the simple cylindrical boring Trypanites, but then you note that they are shallow and have raised rims so that they look like little meteorite craters. These holes thus represent tiny organisms on the bryozoan surface while it was alive. The bryozoan grew around these infesters, producing the reaction tissue of the rims. This is a kind of preservation called bioclaustration (literally, “walled-in life” from the same root in claustrophobia and cloisters). The specimen is from locality C/W-149 (Liberty Formation near Brookville, Franklin County, Indiana; 39º 28.847′ N, 84º 56.941′ W).
Chimneys 153aThis is another trepostome bryozoan with these rimmed pits. It is from locality C/W-153 (Bull Fork Formation near Maysville, Mason County, Kentucky; 38º 35.111′ N, 083º 42.094′ W). The pits are more numerous and have more pronounced reaction rims.
Chimneys 153bA closer view. One of the interesting questions is whether these pits are also borings. Did they cut down into the bryozoan skeleton at the same time it was growing up around them? We should be able to answer that by making a cross-section through the pits to see what their bases look like. The bryozoan walls should be either cut or entire.
Chimneys 153cThis is an older image I made back in the days of film to show the density of the rimmed pits in the same bryozoan as above. If we assume that the pit-maker was a filter-feeding organism, how did it affect the nutrient intake of the host bryozoan? Maybe the infester had a larger feeding apparatus and took a larger size fraction of the suspended food? (This could be a project where we apply aerosol filtration theory.)  Maybe the bryozoan suffered from a cut in its usual supply of food and had a stunted colony as a result? These are questions my students and I plan to pursue this summer and next year.

It is good to get back to the glorious Cincinnatian!

References:

Ernst, A., Taylor, P.D. and Bohatý, J. 2014. A new Middle Devonian cystoporate bryozoan from Germany containing a new symbiont bioclaustration. Acta Palaeontologica Polonica 59: 173–183.

Kammer, T.W. 1985. Aerosol filtration theory applied to Mississippian deltaic crinoids. Journal of Paleontology 59: 551-560.

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

Rubinstein, D.I. and Koehl, M.A.R. 1977. The mechanisms of filter feeding: some theoretical considerations. American Naturalist 111: 981-994.

Tapanila, L. 2005. Palaeoecology and diversity of endosymbionts in Palaeozoic marine invertebrates: trace fossil evidence. Lethaia 38: 89-99.

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

Wooster’s Fossils of the Week: Mysterious borings in brachiopods from the Upper Ordovician of the Cincinnati region

February 2nd, 2014

Half borings 152a1Above is a well-used brachiopod from the Upper Ordovician of northern Kentucky (C/W-152; Petersburg-Bullittsville Road, Boone County; Bellevue Member of the Grant Lake Formation). It experienced several events on the ancient seafloor during its short time of exposure. Let’s put a few labels on it and discuss:

Half borings 152a2Our main topic will be those strange ditch-like borings (A) cut across into the exterior of this brachiopod shell. This is an example of bioerosion, or the removal of hard substrate (the calcitic shell in this case) by organisms. These structures were likely created by worm-like filter-feeders. The shell also has a nice trepostome bryozoan (B) encrusting it (and partially overlapping the borings) and the heliolitid coral Protaraea richmondensis (C), which is distinguished by tiny star-like corallites. The borings are what we need to make sense of in this tableau. Here’s another set on another brachiopod:

Half borings 152bThis closer view of a brachiopod shell exterior from the same locality shows two of these horizontal borings. The mystery is why we see only half of the boring. These are apparently cylindrical borings of the Trypanites variety, but they should be enclosed on all sides as tubes. Why is half missing? It is as if the roofs have been removed. I think that is just what happened.

Half borings 152cThis encrusted and bored brachiopod, again from the same locality, gives us clues as to what likely happened. Here we see an encrusting bryozoan and those borings together. The borings cut through the bryozoan down into the brachiopod shell. Could it be that encrusting bryozoans provided the other half of the borings?

BoringXsectHere’s a test of that idea. Above is a cross-section through the boundary between an encrusting bryozoan (above) and a brachiopod shell (below). It was made by cutting through the specimen, polishing it, and then making an acetate peel. The bryozoan shows the modular nature of its colonial skeleton, and the brachiopod displays its laminar shell structure. The two round features are sediment-filled borings running perpendicular to the plane of the section. The boring on the left is completely within the brachiopod shell; the one on the right is cut along the interface of the bryozoan and brachioopod. Remove the bryozoan and we would have a half-boring as discussed above.

Half borings 152eIf that postulate is true, it means that the encrusting byozoans must have been removed from the brachiopod shells, taking the other halves of the borings with them. We should thus find bryozoans that “popped” off the shells with the equivalent half-borings on their undersides. You know where this is going. The bryozoan above (same locality) shows its upper surface. Note that there are a scattering of tiny borings punched into it.

Half borings 152fThis is the underside of the bryozoan. We are looking at its flat attachment surface. It was fixed to a shell of some kind (I can’t tell what type) and became detached from it. You see the half-borings along with vertical borings drilled parallel to the attachment surface. It appears that small organisms drilled into the bryozoan zoarium (colonial skeleton) on its upper surface, penetrated down to the boundary with the brachiopod shell, and then turned 90° and excavated along the boundary between brachiopod and bryozoan. This makes sense if they were creating a dwelling tube (Domichnia) that they would want surrounded by shell. Punching straight through the bryozoan and brachiopod would leave them in a tube without a base. What would this look like from the inside of the brachiopod shell?

Half borings 152dThis time we’re looking at the interior of a brachiopod shell (same location) that has been exfoliated (some shell layers have been removed). The horizontal borings are visible running parallel to the shell.

Horizontal in bivalveThis view of an encrusted bivalve shell may help with the concept. In the top half you see an encrusting bryozoan. In the bottom you see bivalve shell exposed where the bryozoan has been broken away. Cutting into that shell are the horizontal borings. Their “roofs” were in the now-missing parts of the bryozoan.

There are two conclusions from this hypothesis: (1) There was a group of borers who drilled to this interface between bryozoan and brachiopod skeleton, detected the difference in skeleton type, and then drilled horizontally to maintain the integrity of their tubes; (2) the bryozoans were cemented to the brachiopods firmly enough that the borers could mine along the interface, but later some bryozoan encrusters were removed, leaving no trace of their attachment save the half-bored brachiopod shell. This latter conclusion is disturbing. A tacit assumption of workers on the sclerobionts (hard-substrate dwellers) of brachiopods and other calcitic skeletons is that the calcitic bryozoans cemented onto them so firmly that they could not be dislodged. We could thus record how many shells are encrusted and not encrusted to derive paleoecological data about exposure time, shell orientations and the like. But if the robust bryozoans could just come off, maybe that data must be treated with more caution? After all, bryozoans that were removed from unbored brachiopods could leave no trace at all of their former residence.

Two students and I presented these ideas at a Geological Society of America meeting eight years ago (Wilson et al., 2006), but we never returned to the questions for a full study. Now a new generation of students and I have started a project on this particular phenomenon of sclerobiology. It will involve collecting more examples and carefully dissecting them to plot out the relationship between the borings and their skeletal substrates. We also want to assess the impact these observations may have on encruster studies. Watch this space a year from now!

References:

Brett, C.E., Smrecak, T., Hubbard, K.P. and Walker, S. 2012. Marine sclerobiofacies: Encrusting and endolithic communities on shells through time and space, p. 129-157. In: Talent, J.A. (ed.), Earth and Life; Springer Netherlands.

Smrecak, T.A. and Brett, C.E. 2008. Discerning patterns in epibiont distribution across a Late Ordovician (Cincinnatian) depth gradient. Geological Society of America Abstracts with Programs 40:18.

Wilson, M.A., Dennison-Budak, C.W. and Bowen, J.C. 2006. Half-borings and missing encrusters on brachiopods in the Upper Ordovician: Implications for the paleoecological analysis of sclerobionts. Geological Society of America Abstracts with Programs 38:514.

Wooster’s Fossil of the Week: A trepostome bryozoan from the Upper Ordovician of northern Kentucky

December 15th, 2013

Heterotrypa Corryville 585First, what U.S. state does this delicious little bryozoan resemble? It’s so close I can even pick out Green Bay. This is Heterotrypa frondosa (d’Orbigny, 1850), a trepostome bryozoan from the Corryville Formation (Upper Ordovician) in Covington, Kentucky. I collected it decades ago while exploring field trip sites for future classes. This zoarium (the name for a bryozoan colony’s skeleton) is flattened like a double-sided leaf, hence the specific name referring to a frond. In the view above you can see a series of evenly spaced bumps across the surface termed monticules. A closer view is below.
Heterotrypa closer 585The monticules are composed of zooecia (the skeletal tubes for the individual bryozoan zooids) with slightly thickened walls standing up above the background of regular zooecia. The hypothesized function of these monticules was to make the filter-feeding of the colony more efficient by utilizing passive flow to produce currents and whisk away excurrents from the lophophores (feeding tentacles) like little chimneys. In 1850, Alcide Charles Victor Marie Dessalines d’Orbigny (French, of course) originally named this species Monticulipora frondosa because of the characteristic bumps.
Boring in Heterotrypa 585If you look closely at the zoarium you will see holes cut into it that are larger than the zooecia. A closer view of one is shown above. These are borings called Trypanites, which have appeared in this blog many times. They were cut by some worm-like organism, possibly a filter-feeding polychaete, that was taking advantage of the bryozoan skeleton to make its own home. It would have extended some sort of filtering apparatus outside of the hole and captured organic particles flowing by. It was a parasite in the sense that it is taking up real estate in the bryozoan skeleton that would have been occupied by feeding zooids. It may not have been feeding on the same organic material, though, as the bryozoan. It may have been consuming a larger size fraction than the bryozoan zooids could handle.

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

d’Orbigny, A. D. 1850. Prodro/ne de Paleontologie stratigraphique universelle des animaux mollusques & rayonnes faisant suite au cours elementaire de Paleontologie et de Geologic stratigraphiques, vol. 2. 427 pp. Masson, Paris.

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.

Wooster’s Fossil of the Week: An encrusted cobble from the Upper Ordovician of Kentucky

December 1st, 2013

Ordovician Kope Encrusted Concretion 111813In 1984 I pulled the above specimen from a muddy ditch during a pouring rain near the confluence of Gunpowder Creek and the Ohio River in Boone County, northern Kentucky. It changed my life.
crinoid bryozoan concretion 111813This limestone cobble eroded out of the Kope Formation, a shale-rich Upper Ordovician unit widely exposed in the tri-state area of Kentucky, Indiana and Ohio. It probably is a burrow-filling, given its somewhat sinuous shape. As you can see in the closer view above, it is encrusted with crinoids (the circular holdfasts) and bryozoans of several types, including the sheet-like form in the upper left and the mass of little calcareous chains spread across the center of the view. There are also simple cylindrical borings called Trypanites scattered about.
OrdovicianEdrio113013There were other cobbles at this site as well, including the one imaged above. It shows an encrusting edrioasteroid (Cystaster stellatus, the disk with the star shape in the middle) and a closer view of those chain-like bryozoans (known as Corynotrypa).
Concretion reverse 111813Significantly, the underside of the cobble pictured at the top of the page is smooth and mostly unencrusted, showing just a few of the Trypanites borings. A closer look, though, would reveal highly-eroded remnants of bryozoans. This means that the cobble sat on the seafloor with its upper surface exposed long enough to collect mature encrusters and borers. It appears, though, that the cobbles were occasionally flipped over, killing the specimens now on the underside and exposing fresh substrate for new encrusters.

How did this cobble change my life? My wife Gloria and I were scouting field trip sites for my Invertebrate Paleontology course. I was a very new professor and needed localities for our upcoming travels. I thought I had seen enough during that wet and chilly day, but Gloria wanted to explore one more outcrop. Fine, I thought, we’ll stop here at this muddy ditch and she’ll be quickly convinced it was time to quit. As I stepped out of the car I saw this cobble immediately. Then we both saw that the ditch was full of them. They showed spectacular encrusting and boring fossils with exquisite preservation, but more importantly they demonstrated a process of ecological succession rarely if ever seen in the paleontological record. It led to two papers the following year that came out just before my first research leave in England. There my new interests in hard substrate organisms led me to my life-long friends and colleagues Paul Taylor and Tim Palmer. Since then we’ve published together dozens of papers on encrusters and borers, now known as sclerobionts, and used them to explore many questions of paleoecology and evolution.

Thank you, Gloria, for one more outcrop!

References:

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

Wilson, M.A. 1985b. A taxonomic diversity measure for encrusting organisms. Lethaia 18: 166.

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: Tubular drillholes (Upper Ordovician of the Cincinnati Region)

April 28th, 2013

Trypanites_hardground_585_010213

This is one of the simplest fossils ever: a cylindrical hole drilled into a hard substrate like a skeleton or rock. The above image is of a hardground (cemented carbonate seafloor) from the Upper Ordovician of northern Kentucky with these borings cut perpendicularly to the bedding and descending downwards. Each boring is filled with light-colored dolomite crystals. This boring type is given the trace fossil name Trypanites weisi Magdefrau 1932.
Trypanites_Bryozoan_010213_585Trypanites, shown above cutting into a trepostome bryozoan from the Upper Ordovician of southeastern Indiana, is a very long-ranging trace fossil. It first appears in the Lower Cambrian and it is still formed today — a range of 540 million years (James et al., 1977; Taylor and Wilson, 2003). It was (and is) made by a variety of worm-like organisms, almost always in carbonate substrates. Today the most common producers of Trypanites are some polychaete and sipunculid worms. Trypanites was the most common boring until the Jurassic, when it was overtaken in abundance by bivalve and sponge borings. Trypanites was the primary boring in the Ordovician Bioerosion Revolution (Wilson and Palmer, 2006).
Trypanites_Horizontal_585Trypanites is defined as a cylindrical, unbranched boring in a hard substrate (such as a rock or shell) with a length up to 50 times its width (Bromley, 1972). The typical Trypanites is only a few millimeters long, but some are known to be up to 12 centimeters in length (Cole and Palmer, 1999). The above occurrence of Trypanites is one of my favorites. The organisms bored into a bryozoan colony (the fossil in the upper left and center with tiny holes) and down into a bivalve shell the bryozoan had encrusted. The borer then turned 90° and drilled horizontally through the aragonitic and calcitic layers of the shell. The aragonite dissolved, revealing the half-borings of Trypanites.
LibertyBorings_585In this bedding plane view, Trypanites weisi borings are shown cutting into a hardground from the Liberty Formation (Upper Ordovician) of southeastern Indiana. This is a significant occurrence because the borings are cutting through brachiopod shells cemented into the hardground surface. When the brachiopods are dislodged from the hardground, those with holes in them erroneously appear to have been bored by predators (see Wilson and Palmer, 2001).

The simplest of fossils turns out to have its own levels of complexity!

References:

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

Cole, A.R. and Palmer, T.J. 1999. Middle Jurassic worm borings, and a new giant ichnospecies of Trypanites from the Bajocian/Dinantian unconformity, southern England. Proceedings of the Geologists’ Association 110 (3): 203–209.

James, N.P., Kobluk, D.R. and Pemberton, S.G. 1977. The oldest macroborers: Lower Cambrian of Labrador. Science 197 (4307): 980–983.

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

Wilson, M.A. and Palmer, T.J. 2001. Domiciles, not predatory borings: a simpler explanation of the holes in Ordovician shells analyzed by Kaplan and Baumiller, 2000. Palaios 16: 524-525.

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

Wooster’s Fossil of the Week: A twisty trace fossil (Lower Carboniferous of northern Kentucky)

January 27th, 2013

My Invertebrate Paleontology students know this as Specimen #8 in the trace fossil exercises section: “the big swirly thing”. It is a representative of the ichnogenus Zoophycos Massalongo, 1855. This trace is well known to paleontologists and sedimentologists alike — it is found throughout the rock record from the Lower Cambrian to modern marine deposits. It has a variable form but is generally a set of closely-overlapping burrow systems that produce a horizontal to oblique set of spiraling lobes. It was produced by some worm-shaped organism plunging into the sediments in a repetitive way, gradually making larger and larger downward-directed swirls.

Zoophycos is a useful indicator of ancient depositional conditions. It give its name, in fact, to an ichnofacies — a set of fossils and sediments characterize of a particular environment. In the Paleozoic it is found in shallow water and slope environments; from the Mesozoic on it is known almost entirely from deep-sea sediments. Our specimen is from the Borden Formation and was found amidst turbidite deposits, so it is probably from an ancient slope system.

There has been much debate about the behavior and objectives of the organisms who made Zoophycos. The traditional view is that it was formed by an animal mining the sediment for food particles, a life mode called deposit-feeding. Some workers, though, have suggested it could have been a food cache, a sewage system, and even an agricultural garden of sorts to raise fungi for food. I think in the end the simplest explanatory model is deposit-feeding, although with such a long time range, a variety of behaviors likely produced this trace.

Zoophycos was named in 1855 by the Italian paleobotanist Abramo Bartolommeo Massalongo (1824-1860). Massalongo was a member of the faculty of medicine at the University of Padua, chairing their botany department. (Medicine had broad scope in those days!) Why was he studying this trace fossil? Like most of the early scientists who noticed trace fossils, he thought it was some kind of fossil plant.
Zoophycos villae (Massalongo, 1855, plate 2)

References:

Bromley, R.G. 1991. Zoophycos: strip mine, refuse dump, cache or sewage farm? Lethaia 24: 460-462.

Ekdale, A.A. and Lewis, D.W. 1991. The New Zealand Zoophycos revisited: morphology, ethology and paleoecology. Ichnos 1: 183-194.

Löwemark, L. 2011. Ethological analysis of the trace fossil Zoophycos: Hints from the Arctic Ocean. Lethaia 45: 290–298.

Massalongo, A. 1855. Zoophycos, novum genus Plantarum fossilum, Typis Antonellianis, Veronae, p. 45-52.

Olivero, D. 2003. Early Jurassic to Late Cretaceous evolution of Zoophycos in the French Subalpine Basin (southeastern France). Palaeogeography, Palaeoclimatology, Palaeoecology 192: 59-78.

Osgood, R.G. and Szmuc, E.J. 1972. The trace fossil Zoophycos as an indicator of water depth. Bulletin of American Paleontology 62 (271): 5-22.

Sappenfield, A., Droser, M., Kennedy, M. and Mckenzie, R. 2012. The oldest Zoophycos and implications for Early Cambrian deposit feeding. Geological Magazine 149: 1118-1123.

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.

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.

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.

A Tale of Two Museums: Part 2 — The Creation Museum

December 7th, 2011

The Creation Museum

This past Saturday Elizabeth Schiltz of the Philosophy Department and I took our First-Year Seminar students on a long drive to the infamous Creation Museum in Petersburg, Kentucky. It was a beautiful day and we had a good time, if you set aside the intellectual travesties and pseudoscientific contradictions of the place. Our Wooster students were very polite and inquisitive, and they had many observations after we left the premises. The museum is uber-slick and the staff extremely helpful and friendly. We were on their property and grateful that they are willing to share their story and facilities with anyone who pays admission and follows the rules. Still, we felt both astonished and oppressed by the place.

The scene above is just inside the entrance of the museum. The juxtaposition of an animatronic dinosaur and a happy child tell us much about the philosophy and science of the organization: this is not a museum in the traditional sense. Dinosaurs with people is one thing — the dinosaur not eating the child is another!

Elizabeth’s First-Year Seminar section is titled “On the Meaning of Life“. Her students have been working through worldviews and why people hold them, so this trip was most appropriate. My First-Year Seminar is on “Nonsense and Why it is so Popular“. It is obvious why we were here!

The Creation Museum has been reviewed many times by scientists and other skeptics. (Here is a detailed account of a visit.) I am just presenting our impressions here with a few photographs.

One of the first displays in the Creation Museum is this life-sized diorama of two paleontologists excavating a dinosaur skeleton. (Geologists should note how important they are to the creationist worldview.) The scientist on the right is a traditional evolutionist; the older man on the left is a heroic scientific creationist we meet several times later in displays and videos. Both are looking “at the same facts”, but they have different “perspectives” and reach wildly different conclusions. From the start we saw a surprisingly post-modern view of science — it is all in the presuppositions of the observer with the “facts” as just a text for subjective analysis.

Especially to a geologist, the time scale of creationists is bizarre. At the Creation Museum the old Archbishop Ussher chronology is used, giving the first year of the Universe as 4004 BC. Here you see the timeline combined with the “7 C’s of History“. A literal reading of Genesis (and the rest of the Bible) is essential to the Young Earth Creationist view of Christian salvation.

An irony much noted by our students is that throughout the Creation Museum the displays denigrate “human reason” and elevate “God’s Word”, yet they appeal to human reasoning in every display of “evidence” and argument. Here we see the peculiar creationist view of “evolution within kinds” which allows for “microevolution” but not the appearance of new kinds of life. (Yes, there is a very fuzzy definition for “kind”.)

We all agreed that the models for Adam and Eve were … well … hot. They were so well done that, in this case especially, we felt like we were intruding on intimate moments. Just above this happy pair, out of view, the snake awaits with his temptation.

After their disobedience to God and their Fall, Eve and Adam look far less babelicious. Here they are making a bloody sacrifice for their Original Sin. Lots more blood and angst follows.

The Flood of Noah gets a lot of attention, of course, at the Creation Museum. Among many other things, it is used to explain the fossil record and the current distribution of life. I suspect the museum designers also derive a bit of pleasure from the idea of sinners dying in misery and despair as a small remnant of the righteous survives.

A critical part of the message in this museum is that the “evolutionary worldview” has brought much pain and destruction to our civilization. This elaborate and rather odd display shows the concept of “millions of years” destroying a church building. (Just think what billions of years would do!) Again, note the threat of modern geology to the fabric of God-fearing society.

Dinosaurs are a huge part of the Creation Museum’s program. Because kids love them so much, the Answers in Genesis people call them “missionary lizards“. (I don’t know which is most offensive: calling them missionaries … or calling them lizards!) The dinosaur models are, like their human equivalents, spectacular. Their star T. rex looks a bit overweight, but otherwise the reconstructions would pass in a real museum. The information on the signs, of course, is another story. Note the approximate date for the Upper Jurassic and that they ate meat only after the Fall. (Before that there was no death on Earth and thus no predation.)

Most disturbing is the effect of an institution like the Creation Museum on the education of children. This display makes sure you get the point that kids are at last hearing the real story outside of their corrupting public schools. The museum caters to home-schooled children for their “science” components, as well as to many private Christian schools. We often overheard parents and teachers telling their students “what we believe”. I caught a couple conversations describing a fallacious view of evolution (using the classic “I don’t know why there are still monkeys if we evolved from them” argument) that will likely go unchallenged in that child’s life. Very sad.

At the end of our experience we visited the outdoor portion of the museum with beautiful gardens and, to our delight, a petting zoo! This was the best way to discharge the tension built up during our visit: playing with innocent goats, feeding llamas, and watching albino peacocks display. All products of a long evolutionary history despite whatever stories we tell.

 

 

 

 

 

Wooster’s Fossil of the Week: An edrioasteroid (Upper Ordovician of Kentucky)

July 24th, 2011

This week’s fossil appeared previously in this blog when we discussed hiatus concretions and their fossil fauna. It is one of my favorites for both how we found it (see the entry linked above) and the way it introduced me to hard substrate fossils (it was my first). The edrioasteroid is the circular fossil in the center. Above it is a branching cyclostome bryozoan that will be the subject of another story someday. These fossils were found in the Kope Formation (Cincinnatian Group) of the Upper Ordovician in northern Kentucky, making them about 450 million years old.

Edrioasteroids (“seated stars”) were echinoderms (spiny-skinned animals) that lived from the Cambrian through the Permian periods (Sumrall, 2009). Their living relatives today include sea stars, sea urchins, sand dollars and crinoids. Edrioasteroids have a flattened disk-like body called a theca covered with plates of calcite. They attached themselves to hard substrates like shells, hardgrounds or cobbles (as in the photo above). On the upper surface of the theca are ambulacra extending outward from a central mouth. The anus is a little circular set of plates between two of the ambulacra. The ambulacra themselves had tiny little tube feet that extended upwards into the seawater  for filter-feeding suspended organic matter.

The fossil above, also represented in the diagram below, is Cystaster stellatus (Hall, 1866). It is a small edrioasteroid, as the group goes, and is characterized by straight, wide ambulacra.

(Image from the Cincinnati Dry Dredgers’ wonderful website.)

(Image from the public domain Encyclopaedia Britannica, 11th Edition.)

Edrioasteroids are favorite fossils for collectors. I learned this when I published a paper on the fauna that included the fossils above (Wilson, 1985) and later the outcrop was pillaged — not a single edrioasteroid remains there from the hundreds originally found.

References:

Sumrall, C.D. 2009. First definite record of Permian edrioasteroids; Neoisorophusella maslennikovi n. sp. from the Kungurian of northeast Russia. Journal of Paleontology 83: 990-993.

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

The paleontology of hiatus concretions: fossils without sediment

December 15th, 2010

Bryozoans (the thin branching structures) and an edrioasteroid (with the "star") encrusting a hiatus concretion from the Kope Formation (Upper Ordovician) of northern Kentucky.

Way back in 1984, when I was just a green Assistant Professor of Geology, my wife Gloria and I explored a series of Upper Ordovician (about 445 million years old) outcrops in northern Kentucky to plan a paleontology course field trip. It was a rainy day were, as is too often the case, slippery with mud. On our last roadcut exposure of the day I stepped out of the car and found at my feet the cobble pictured above. It had edrioasteroid echinoderms and bryozoans encrusting it on all sides — and we knew we had found something special. We collected dozens of the cobbles in a few minutes. It changed my research trajectory by introducing me to the splendors of hard substrate communities and hiatus concretions.

This post is a celebration of another chapter of that work published next month in the journal Facies (volume 57, pp. 275-300). This time I’m a member of a large team led by my young friend and colleague Michal Zaton of the University of Silesia in Sosnowiec. We thoroughly examined a set of bored and encrusted cobbles from the Middle Jurassic (about 170 million years old) of south-central Poland. It was a pleasure to use some of the same research techniques I employed 26 years ago to help reconstruct an ancient ecosystem and environment.

Hiatus concretions from the Middle Jurassic of Poland.

These cobbles are known as “hiatus concretions” because they collect in an environment when sediment has stopped (gone on “hiatus”, I suppose) and a lag of hard debris accumulates when fine sediment is washed away by currents. Organisms which require a hard substrate (“sclerobionts”) encrust the cobble surfaces (bryozoans, echinoderms, oysters and serpulid worms are most common) or bore into the matrix (sponges, bivalves, barnacles and worms commonly do this). A fossil record thus is formed in the absence of sedimentation, which is a bit different from the usual paradigm.

Various encrusters and borings on hiatus concretions from the Middle Jurassic of Poland.

Encrusting bryozoans on hiatus concretions from the Middle Jurassic of Poland.

I enjoy studying marine hard substrate organisms through time because they show a type of community evolution over hundreds of millions of years. These diverse fossils have also provided countless research opportunities for my Wooster students, and tracking them down has taken us all over the world and throughout the geological column. (The Cretaceous of Israel is another recent example of this work.) It is very satisfying to see a young geologist like Michal Zaton finding pleasure and research success in the same pursuit.

Bryozoans and crinoid holdfasts encrusting a cobble from the Upper Ordovician Kope Formation of northern Kentucky.

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