Presenting a Jurassic echinoid story on the last day of GSA 2012

November 7th, 2012

CHARLOTTE, NORTH CAROLINA–The last day of a scientific meeting is always less frantic. About half the attendees have left for home, the exhibitors start to give away merchandise so they don’t have to ship it home, and the speakers are a bit more relaxed. Meagen Pollock and I had talks on this final day of the Geological Society of America annual meeting. It felt good to finally give them to audiences made up in large part by our friends and students. I am simply presenting here a few of my slides, including the title image above. The story you may have read in bits and pieces in the Israel entries at this blog. Here is our abstract.

The second group of Wooster GSA 2012 posters

November 5th, 2012

CHARLOTTE, NORTH CAROLINA–Matt Peppers (’13), a member of the intrepid Team Utah, presented his poster today at the 2012 Geological Society of America annual meeting. Matt is working on the dynamics of the volcanic flows in the Black Rock Desert. Here is his abstract.

Melissa Torma (’13) showed her poster in the same session. She worked in the Negev of southern Israel on the Middle Jurassic Matmor Formation fauna. Her GSA abstract is here.

The third Wooster presenter was Richa Ekka (’13), who worked on Saaremaa Island in Estonia this summer. Her abstract describing her project with a Silurian shallow water dolomitic sequence is here.

Once again it was a joy to watch our students interact with the many geologists who discussed their posters and projects. I now can’t imagine coming to these meetings without an enthusiastic group of our students.

Wooster’s Fossils of the Week: Sea urchin bits (Middle Jurassic of southern Israel)

September 2nd, 2012

Our fossils this week come from our growing collection of material found in the Matmor Formation (Callovian-Oxfordian) of Makhtesh Gadol, southern Israel. In November I will be giving a talk at the annual meeting of the Geological Society of America in Charlotte, North Carolina, on the taphonomy of Matmor regular echinoids (“sea urchins”). The abstract is online. Taphonomy is the study of the fossilization process. In this case it is essentially what happened to the echinoid remains after death and before final burial. This part of the fossilization history can tell us much about the environment of deposition of the Matmor Formation. The image above is one of the rare complete tests (skeletons) in our study. It is probably a rhabdocidarid echinoid, but the preservation is not quite good enough to tell.

Echinoids are especially interesting for this kind of work. (That link will send you to a wonderful site explaining all you’ll want to know about echinoids and their evolutionary history.) They originated way back in the Ordovician Period, about 450 million years ago, and have retained the same general skeletal structure since then. Their response to physical and chemical conditions on the ocean floor has thus been consistent over time, and we can experiment with modern representatives to estimate their decay and disarticulation processes.

Typical test plate fragments from a rhabdocidarid echinoid in the Matmor Formation. The specimen on the right is encrusted by a very thin plicatulid bivalve, which is in turn encrusted by small branching stomatoporid bryozoans.

A flattened and thorny rhabdocidarid spine. The left end has a socket that attached to a tubercle (bump) on the test of the echinoid.

This cool spine was apparently bitten by a Jurassic fish! Wish I had at least one of that fish’s teeth.

The strange swollen sphere with little holes at the base of this echinoid is a cyst that likely formed from a copepod parasitic infection. Neat (and so far undescribed in the literature).

We can conclude that the Matmor Formation was deposited in very shallow, warm marine waters, probably lagoonal (a favorite living place for rhabdocidarid echinoids), that were only occasionally disturbed by storms and “burial events”. The echinoids decayed and disarticulated on the seafloor (a process that takes about a week) and the pieces tossed around for awhile gathering sclerobionts (encrusters, in this case) and experiencing significant abrasion. This matches other evidence from our previous paleontological studies of the Matmor’s depositional environment.


Donovan, S.K., and Gordon, C.M., 1993, Echinoid taphonomy and the fossil record: Supporting evidence from the Plio-Pleistocene of the Caribbean. Palaios, v. 8, p. 304-306.

Greenstein, B.J., 1991, An integrated study of echinoid taphonomy: Predictions for the fossil record of four echinoid families: Palaios, v. 6, p. 519-540.

Greenstein, B.J., 1992, Taphonomic bias and the evolutionary history of the Family Cidaridae (Echinodermata: Echinoidea): Paleobiology, v. 18, p. 50-79.

Greenstein, B.J., 1993, Is the fossil record of the regular echinoid really so poor? A comparison of Recent and subfossil assemblages: Palaios, v. 8, p. 587-601.

Kidwell, S.M. and Baumiller, T., 1990, Experimental disintegration of regular echinoids: Roles of temperature, oxygen and decay thresholds: Paleobiology, v. 16, p. 247-271.

Wooster’s Fossils of the Week: an enigmatic set of tubes (Middle Jurassic of Poland)

August 26th, 2012

The fossils this week celebrate the appearance of an article in the latest issue of Palaios authored by an international team led by my good friend and colleague Michał Zatoń (University of Silesia, Poland). The fossils are strange polka-dotted tubes encrusting Middle Jurassic oncoids and concretions from the Polish Jura — a place I enjoyed visiting last summer with Michał. The fossils were quite mysterious to us, but with the help of our new colleague Yasunori Kano (The University of Tokyo), we think we now have a good idea what they represent. Above you see one of the tubes on a concretion.
The polka dots are actually small, regular divots in the sides of the tubes, as shown above in this view through a scanning electron microscope. It turns out that these concavities are the same size as ooids (rounded carbonate grains) in the depositional environment. In fact, occasional ooids are still in their holes, as shown by the white arrow in the image.
In this cross-section through one of the tubes, each of the exterior holes is lined with a thin layer of carbonate, which is apparently the outer layer of an ooid that was cemented into each space. The tube itself is completely occupied by fine carbonate sediment.

Our hypothesis is that the tubes were formed by some sort of polychaete worm similar to serpulids and sabellids (with which they are associated). The worm may have built a hollow living tube by gluing ooids together and possibly taking advantage of the quick-cementing characteristics of this Jurassic calcite sea. It may have then fed on the surrounding microbial mats that covered the concretion and oncoid surfaces. This hypothesis explains the sessile nature of the tubes, their shape and construction, and their association with thin mineralized layers formed by cyanobacteria.

No polychaetes today are known to build living tubes out of ooids, so these Jurassic forms are thus far unique in the fossil and living record. It was a fun paleontological puzzle to tackle with my friends!

We are proud that our little study was chosen as the cover story for the August 2012 issue of Palaios:

“Unusual tubular fossils associated with microbial crusts from the Middle Jurassic of Poland. Upper left, an exposure of Middle Jurassic (Bathonian) clays at Ogrodzieniec in the Polish Jura; lower left, ESEM pictures of morphology and structure of the Middle Jurassic tubular fossils interpreted as remnants of agglutinated polychaete tubes; lower right, two pictures of tubular fossils encrusting oncoid and concretion; upper right, two pictures of recent agglutinated polychaete tubes from Japan.”


Zatoń, M., Kano, Y., Wilson, M.A. and Filipiak, P. 2012. Unusual tubular fossils associated with microbial crusts from the Middle Jurassic of Poland: agglutinated polychaete worm tubes? Palaios 27: 550-559.

Zatoń, M., Kremer, B., Marynowski, L., Wilson, M.A. and Krawczynski, W. 2012. Middle Jurassic (Bathonian) encrusted oncoids from the Polish Jura, southern Poland. Facies 58: 57–77.

Patchiness and ecological structure in a Middle Jurassic equatorial crinoid-brachiopod community (Matmor Formation, Callovian, southern Israel) — An abstract submitted to the Geological Society of America for the 2012 annual meeting

August 6th, 2012

Editor’s note: The Wooster Geologists in Israel this spring wrote abstracts for the Geological Society of America Annual Meeting in Charlotte, North Carolina, this November. The following is from student guest blogger Melissa Torma in the format required for GSA abstracts:

TORMA, Melissa, WILSON, Mark A., Department of Geology, The College of Wooster, Wooster, OH 44691 USA; FELDMAN, Howard R., Division of Paleontology (Invertebrates), American Museum of Natural History, New York, NY 10024

The Matmor Formation is a Middle-Upper Jurassic (Callovian-Oxfordian) marl and limestone unit entirely exposed in Hamakhtesh Hagadol in the Negev of southern Israel. It was deposited in shallow marine waters very close to the paleoequator in the Ethiopian Province of the Tethyan Faunal Realm. It is very fossiliferous throughout most of its 100 meters of thickness. The Matmor Formation has been well described stratigraphically, and several of its fossil groups have been taxonomically assessed (notably the brachiopods, ammonites, crinoids and sclerobionts), but there is yet no community-level analysis of the entire fauna. This work is part of that larger paleoecological project. We systematically collected from the most fossiliferous unit of the Matmor (SU 51 in the local stratigraphy; upper Callovian; Quenstedtoceras (Lamberticeras) lamberti Zone) over several kilometers. The community in this marl is dominated by abundant crinoids (a new species of Apiocrinites), rhynchonellid (Somalirhynchia and Burmirhynchia) and terebratulid (Bihenithyris and Digonella) brachiopods, echinoids (mostly rhabdocidarids), calcisponges and scleractinian corals. Mollusks, other than small attached oysters, are relatively rare, and bryozoans are represented by only a few encrusters. The fossils are concentrated in patches a few tens of meters in diameter separated from each other by featureless, unfossiliferous yellow marl. The patches share many of the same common taxa (especially the crinoids and brachiopods) but differ in the relative abundance of corals. No infauna has been found in this unit, either as trace or body fossils. The environment appears to have been a shallow water embayment with a muddy substrate. Patches of epifauna developed as shelly islands across this seafloor. Crinoids and small corals may have been the pioneers on this soft bottom, providing increasing amounts of skeletal debris to facilitate the settlement of brachiopods and other invertebrates. A periodic influx of fine sediment during storms limited the diversity of this assemblage by smothering patches under several centimeters of mud. This community was thus kept in its early successional stages by periodic disturbance.

Wooster’s Fossil of the Week: an encrusted plesiosaur vertebra (Jurassic of England)

July 29th, 2012

The weathered bone pictured above sits on my desk as a treasured memento. It is the centrum of a plesiosaur vertebra. I found it in the Faringdon Sponge Gravels (Lower Cretaceous) of Oxfordshire, England, during my first research leave (1985). I was working on a project involving encrusters, borers and nestlers (now called sclerobionts) on and in cobbles in this marine gravel (Wilson, 1986). This bone rolled out of the gravels at my feet during a particularly rainy field day.

But why do I say in the title that this vertebral fragment is Jurassic if it is found in a Cretaceous deposit? Because it is what paleontologists call a remanié fossil, a fossil reworked from an earlier deposit into a later one. During the Early Cretaceous, tidal currents worked on an exposure of Jurassic claystones in what will become southern England, eroding bones and other Jurassic debris and transporting them into a gravel-filled channel.

This gravel consisted of bones, shells, quartzite pebbles and claystone cobbles. It was tossed around under marine conditions, with many of their surfaces encrusted and bored by invertebrates. If you look closely at the end-on view above, you can see some lighter-colored patches that represent little calcareous sponges. When I collected this bone these sponges were the important parts. Now I’m impressed more by the fact that it is a bit of plesiosaur.

Plesiosaurs (the name means “near-lizard”) were magnificent marine reptiles of the Jurassic and Cretaceous. They were extraordinary predators on a variety of animals, and despite their bulk were highly maneuverable because of their four large paddle-like appendages. My little bone is too weathered to place in the complex plesiosaur skeleton, other than to say it is probably from the back rather than the neck or tail. Rather than me wax poetic on the Plesiosauria, you might want to visit

The first plesiosaur (Plesiosaurus dolichodeirus) was found by one of the most famous paleontologists of the 19th Century: Mary Anning (1799-1847). Anning was a spectacularly successful fossil collector along the “Jurassic Coast” of southern England. She had a tough life, selling fossils to support her family. She discovered many Jurassic fossils, from ammonites to ichthyosaurs and plesiosaurs. The paleontological establishment at the time often bought fossils from her, but they didn’t always give her credit for her work.

Little known fact: Mary Anning was the inspiration for the classic tongue-twister, “She sells seashells on the seashore. The shells she sells are seashells, I’m sure. So if she sells seashells on the seashore, then I’m sure she sells seashore shells.” I’m sure she’s proud!

To Mary Anning and her magnificent plesiosaur!


Conybeare, W.D. 1824. On the discovery of an almost perfect skeleton of the Plesiosaurus. Transactions of the Geological Society of London, Second series; 1 p. 381-389.

Goodhue, T.W. 2002. Curious Bones: Mary Anning and the Birth of Paleontology (Great Scientists). Morgan Reynolds.

Wilson, M.A. 1986. Coelobites and spatial refuges in a Lower Cretaceous cobble-dwelling hardground fauna. Palaeontology 29: 691-703.

Wooster’s Fossils of the Week: ribbed brachiopods (Middle Jurassic of Israel)

July 15th, 2012

These delightful brachiopods are from the Matmor Formation (Jurassic, Callovian) of the Negev in southern Israel. They are part of a long-term Wooster project describing and interpreting a diverse paleocommunity. The latest trip to study these fossils was this past March with Melissa Torma and our Israeli colleague Yoav Avni. The shells above are Burmirhynchia jirbaenesis Muir-Wood 1935. We identified them using the excellent work on Matmor brachiopods by Feldman et al. (2001).

The location in Makhtesh Gadol, Negev, Israel, where these specimens were collected.

Burmirhynchia jirbaensis was originally named from a collection of specimens found in the Biheh Limestone of the Jirba Range in British Somaliland (modern-day Somalia). This is a wonderful place for Jurassic paleontology, but not one I’m likely to visit soon!

Burmirhynchia is an important brachiopod in the Jurassic of the Tethyan Realm. It has been found throughout the Middle East, southern Europe, Africa and Australia. It has, apparently, been overly “split” into over 90 species, most of which are dubious at best (Shi and Grant, 1993). B. jirbaensis, though, is a legitimate species based on internal characteristics you can only see by sectioning or internal tomography (Feldman et al., 2001).

The genus Burmirhynchia was described in 1918 by an interesting character: Sydney Savory Buckman (1860-1929). Buckman is best known for his work on ammonites, but he was also a novelist, social reformer and (gasp) a fossil dealer (to support his geological work). He was born in Cirencester, England, but grew up in Dorset among some of the most spectacular Jurassic geology in the world. Buckman was briefly a farmer, but he most enjoyed amateur geology and working on collections in local museums. Ammonites were his passion — he worked on several large monographs describing hundreds of new species. (The complaints about his taxonomic splitting began then.) His most eccentric idea was that ammonites may have suffered from a kind of flatulence produced by “nervous apprehension of danger”, with the resulting gas increasing their buoyancy and helping them flee to safety. I don’t recall hearing that one in school!

Curiously enough, Sydney Savory Buckman made one progressive addition to the vocabulary of paleontology: in 1893 he invented the term “palaeo-biology” (Sepkoski, 2012).


Buckman, S.S. 1918. The Brachiopoda of the Namyau Beds, Northern Shan States, Burma. Memoirs of the Geological Survey of India, Palaeontologia lndica, new series 3: 1-299.

Feldman, H.R., Owen, E.F. and Hirsch, F. 2001. Brachiopods from the Jurassic (Callovian) of Hamakhtesh Hagadol (Kurnub Anticline), southern Israel. Palaeontology 44: 637–658.

Sepkoski, D. 2012. Rereading the Fossil Record: The Growth of Paleobiology as an Evolutionary Discipline. University Of Chicago Press, Chicago, 440 pages.

Shi, X. and Grant, R.E. 1993. Jurassic rhynchonellids: internal structures and taxonomic revisions. Smithsonian Contributions to Paleobiology, Number 73, 190 pages.

Wooster’s Fossils of the Week: Wiggly little foraminiferans from the Middle Jurassic of southern England

July 1st, 2012

These shell fragments are of the oyster Praeexogyra hebridica var. elongata, and I picked them up long ago from a remarkable unit made almost entirely of them. It is the Elongata Bed at the base of the Frome Clay (Middle Jurassic) near Langton Herring in Fleet Lagoon, Dorset, England. (See House (1993) for more details, and this site has a nice geological map.) Nearly every oyster piece is covered with elongated, flaky white encrusters easily overlooked. They are attached foraminiferans known as Vinelloidea crussolensis Canu, 1913. (I labelled the specimens with the better-known name “Nubeculinella Cushman, 1930″ when I collected them. Voigt (1973) had earlier shown that this genus is a junior synonym of Vinelloidea. I should have known better.)

Vinelloidea is in the Order Miliolida of the Foraminifera. It is a very common sclerobiont in shallow water Jurassic and Cretaceous deposits, especially in western Europe. Curiously, I’ve not yet seen it in the Jurassic or Cretaceous of Israel, and I’ve looked very hard at the encrusting faunas there. Vinelloidea grew as a series of glassy chambers across shells, pebbles and hardgrounds (Reolid and Gaillard, 2007; Zaton et al., 2011). When the conditions were right, as they were in the Middle Jurassic in southern England, it could be one of the most abundant encrusting organisms in life’s history.


Canu, F. 1913. Contribution à l’étude des Bryozoaires fossiles XIII. Bryozoaires jurassiques. Bulletin de la Société géologique de France, série 4, 13:267-276.

Cushman, J.A. 1930. Note sur quelques foraminifères jurassiques d’Auberville (Calvados). Bulletin de la Société linnéenne de Normandie, série 8, vol. 2 (1929): 132-135.

House, M.E. 1993. Geology of the Dorset Coast. Geologists Association Guide No. 22. 2nd edition, 164 pages.

Reolid, M. and Gaillard, C. 2007. Microtaphonomy of bioclasts and paleoecology of microencrusters from Upper Jurassic spongiolithic limestones (External Prebetic, southern Spain). Facies 53: 97-112.

Voigt, E. 1973. Vinelloidea Canu, 1913 (angeblich jurassische Bryozoa Ctenostomata) = Nubeculinella Cushman, 1930 (Foraminifera). Paläontologische Abhandlungen 4: 665-670.

Zaton, M., Machocka, S., Wilson, M.A., Marynowski, L. and Taylor, P.D. 2011. Origin and paleoecology of Middle Jurassic hiatus concretions from Poland. Facies 57: 275-300.

Wooster’s Fossils of the Week: dinosaur gastroliths (Jurassic of Utah, USA)

June 10th, 2012

These rounded stones are labeled in our collections as gastroliths (literally “stomach stones”) from Starr Springs near Hanksville, Wayne County, Utah. I’m featuring them this week in honor of our Utah Project team working right now in the baking Black Rock Desert near Fillmore, Utah.

From their reported location, these stones are likely out of the Summerville Formation (Middle-Upper Jurassic) and, in another plausible supposition, probably from some sort of dinosaur. Sometimes we just have to trust the labels on our specimens, at least for educational purposes!

My friend Tony Martin recently wrote an excellent blog post on gastroliths, so I won’t repeat his insights here. The general wisdom is that these stones were consumed by herbivorous dinosaurs to aid in their digestion. They would have lodged them in the equivalent of a gizzard and used them to grind their food, much like modern birds. (And yes, dinosaurs were birds themselves.) Gastroliths usually have a resistant lithology to be useful as grinders. The gastroliths above are chert, one of the hardest rock types.

Identifying gastroliths correctly is a bit of a challenge if you don’t find them inside a dinosaur skeleton. The most common indicators are that they are very smooth, are in a location where they were unlikely to have been transported inorganically, and are of a lithology unlike the surrounding rock (“exotics” as geologists like to call them). Still, even with all these criteria met, we must be a tad suspicious if we didn’t find them associated with dinosaur bones. I would never, for example, buy a gastrolith in a rock shop. Without context, it could be just a stream-worn stone. I’m trusting the label on ours that we have the real deal!


Stokes, W.L. 1987. Dinosaur gastroliths revisited. Journal of Paleontology 61: 1242-1246.

Wings, O. 2007. A review of gastrolith function with implications for fossil vertebrates and a revised classification. Acta Palaeontologica Polonica 52: 1-16.

Wooster’s Fossils of the Week: A calcareous sponge with a crinoid holdfast (Matmor Formation, Middle Jurassic, Israel)

April 8th, 2012

The Class Calcarea of the Phylum Porifera is a group of sponges characterized by spicular skeletons made of calcium carbonate (calcite in this case). The spicules (small elements of the skeleton) are often fused together, causing the sponges to look a bit like corals or bryozoans. They are among the most common fossils in the Matmor Formation (Middle Jurassic, Callovian) of southern Israel. Melissa Torma and I collected this particular fossil on our expedition last month. It is another indication that the Matmor Formation was deposited in very shallow waters.
This is the underside of the Matmor calcareous sponge. (I wish we had a name for it, but the taxonomy is in considerable flux right now.) You can see the way it grew radially around an encrusting center. In the lower right a circular oyster attachment is visible.
A close view of the top surface of the calcareous sponge showing radiating canals called astrorhizae. They were used to channel water currents for the sponge’s filter-feeding system.
This crinoid holdfast (the base of an attaching stem) locked onto the calcareous sponge after its death. We can tell this because it is bound to the spicular skeleton itself, which was only exposed after the sponge’s soft tissues rotted away. It is not possible to identify the crinoid, but it is likely in the genus Apiocrinites.
The Class Calcarea was named by James Scott Bowerbank in 1864. Bowerbank (1797-1877) was an English naturalist born in London. He helped run a distillery with his brother, making enough money to support his diverse interests in natural history. He collected many fossils in his life, specializing in the London Clay (Eocene). His various publications gained him membership in the Royal Society in 1842. His greatest work was probably a four-volume set titled “A Monograph of the British Spongidae”. (You can read at least part of this work online.) He was well known as a strong supporter of young scientists, opening his home and collections (and use of his valuable microscopes) to all those seriously interested in natural history. I like to think he would have been happy as a liberal arts geology professor!

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