Archive for the 'Uncategorized' Category

Wooster’s Fossil of the Week: A worm-like gastropod from the Pliocene of Cyprus

January 9th, 2015

Vermetus Pliocene Cyprus aperture viewThis week we continue with fossils from the Nicosia Formation (Pliocene) of the Mesaoria Plain in central Cyprus. These fossils are from a Keck Geology Consortium project in 1996 with Steve Dornbos (’97). Above we have one of the most distinctive forms at the Coral Reef locality: the gastropod Vermetus Daudin, 1800. It doesn’t look much like a snail with its irregular, twisty tube of a shell, but the animal within was very snaily indeed.
Vermetus Pliocene CyprusVermetus and its relatives are still alive today, so we know a lot about their biology. They are sessile benthic, cemented, filter-feeding marine organisms, meaning they are stationary on some hard oceanic substrate sorting out organic materials from the water. They gather their food in one of two ways: capturing plankton in their gills (much like most bivalves) or making a net of mucus threads that is gathered occasionally with their radulae, with the food passed to the mouth. They have separate sexes. The male broadcasts sperm into the water column. The female catches some of this sperm in her mucus feeding net. She then broods the fertilized eggs in her mantle cavity. Vermetids are common enough that they are even used today to determine tectonic movements in the Mediterranean (Sivan et al., 2010).

The genus Vermetus was named in 1800 by François Marie Daudin (1774-1804). Daudin was a French zoologist with a hard, short but very productive life. He contracted a disease in childhood that left his legs paralyzed, and thereafter devoted his time to natural history. He started (but did not complete) one of the first modern books on ornithology, combining description with Linnean taxonomy. His work on amphibians and reptiles was epic, finishing eight volumes that described 517 species. In all his research he was helped by his wife Adèle, who drew his hundreds of illustrations, including those below. She died of tuberculosis in 1804, and he died soon after only 29 years old. They both lived in poverty in Paris during the dislocations of the French Revolution.
Screen Shot 2014-12-31There are no portraits of François Marie Daudin, so the best I can do in his memory is reproduce some of the illustrations of modern Vermetus (drawn by Adèle Daudin) in his 1800 book titled (in translation) “Collection of memories and notes on new or little-known species of molluscs, worms and zoophytes”. Here’s to our memory of the Daudins.


Cowper Reed, F.R. 1935. LII.—Notes on the Neogene Faunas of Cyprus.—III. The Pliocene Faunas. Journal of Natural History 16: 489-524.

Daudin, F.M. 1800. Recueil de Mémoires et de Notes sur des espèces inédites ou peu connues de Mollusques, de Vers et de Zoophytes, orné de gravures. Chez Fuchs, Libraire, rue des Mathurins. Treuttel et Wurtz, quai Voltaire; 50 pp.

Dornbos, S.Q. and Wilson, M.A. 1999. Paleoecology of a Pliocene coral reef in Cyprus: Recovery of a marine community from the Messinian Salinity Crisis. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 213: 103-118.

Sivan, D., Schattner, U., Morhange, C. and Boaretto, E. 2010. What can a sessile mollusk tell about neotectonics? Earth and Planetary Science Letters 296: 451-458.

Wooster’s Fossil of the Week: An encrusted scallop from the Pliocene of Cyprus

January 2nd, 2015

Chlamys Pliocene CyprusOne of the very best paleontological sites I had the pleasure of collecting was on the hot Mesaoria Plain near the center of the island of Cyprus. It was the summer of 1996 and Steve Dornbos (’97) and I were pursuing research as part of a Keck Geology Consortium project. We were exploring the Nicosia Formation, a Pliocene series of thick marls with occasional fossiliferous beds. We stumbled across a remarkable fossil coral reef preserved in a hillside. This deposit and its fossils became the basis of Steve’s Independent Study project and a paper (Dornbos and Wilson, 1999). One of the most prominent (and beautiful) fossil types we found was the pectinid clam Chlamys. The specimen above fell into our category of “Chlamys sp. 1″ because we couldn’t further identify it. Note that it has near the hinge on the left a juvenile Chlamys attached to it, as well as a circular serpulid tube near the top center. The details of the shell are very well preserved.
Chlamys interior Pliocene CyprusThis is the interior view of the same specimen of Chlamys. Visible at the hinge is the isodont dentition and, extending to the left, the distinctive auricle of the genus. On the right side of the hinge is a bit of the young Chlamys.

This species of Chlamys likely nestled between the branches of the coral in our reef, opening its valves to filter-feed. It was not a swimmer like some of its thin-valved, symmetrical pectinid cousins living in the same reef.
Peter Friedrich RödingChlamys was named in 1798 by Peter Friedrich Röding (1767–1846), a German naturalist who lived in Hamburg. He chose the name from the Greek chlamys (χλαμύς) because he thought it looked like the folds of this ancient Greek cloak. In 1798 Röding published a sale catalogue of mollusk shells (fossil and modern). The descriptions of specimens were minimal, but he had long lists of new taxonomic names, making him the official author of dozens of molluscan genera. Strangely, Röding didn’t put his name on the catalogue. He was only officially recognized as its author by a ruling of the International Commission on Zoological Nomenclature in 1956, thus ensuring the perpetuation of his name in our taxonomic system.

We’ll see more gorgeous fossils from the Pliocene of Cyprus in the coming weeks.

Wooster’s Fossil of the Week feature is four years old today. There have been 208 posts in this series, starting with the first posted on January 2, 2011. I hope there are many more to come!


Dornbos, S.Q. and Wilson, M.A. 1999. Paleoecology of a Pliocene coral reef in Cyprus: Recovery of a marine community from the Messinian Salinity Crisis. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 213: 103-118.

Röding, P.F. 1798. Museum Boltenianum sive catalogus cimeliorum e tribus regnis naturæ quæ olim collegerat Joa. Fried Bolten, M.D. p. d. per XL. annos proto physicus Hamburgensis. Pars secunda continens conchylia sive testacea univalvia, bivalvia & multivalvia. – pp. [1-3], [1-8], 1-199. Hamburgi, Trapp.

Wooster’s Fossil of the Week: A Cretaceous oyster with borings and bryozoans from Mississippi

December 26th, 2014

Exogyra costata Prairie Bluff Fm Maastrichtian 585
As winter closes in on Ohio, I start dreaming about past field trips in warm places. This week’s fossil takes me back to fieldwork in Alabama and Mississippi during May of 2010. Paul Taylor (The Natural History Museum, London) and I studied the Upper Cretaceous and Lower Paleogene sections there with our students Caroline Sogot and Megan Innis (Wooster ’11). We had a most excellent and productive time.

The above fossil was very common in our Maastrichtian (Upper Cretaceous) outcrops. It is a left valve of Exogyra costata Say, 1820, from the Prairie Bluff Chalk Formation exposed in Starkville, Mississippi (locality C/W-395). It is a large oyster with a very thick calcitic shell. It has a distinctive spiral, making it look a bit like a snail. Oysters are sessile benthic filter-feeders that usually sit on their large left valves with a flatter and smaller right valve on top. Exogyra stayed stable on the seafloor because of its massive weight.
Interior left 111914This is a view of the inside of the left valve at the top of this entry. You can see the large, dark adductor muscle scar in the center. (The adductors closed the valves.) Note the many evenly-spaced holes in the oyster shell interior, with a closer view below.
Entobia 111914These holes were excavated by a clionaid sponge, producing the trace fossil Entobia. The sponge used the oyster shell as a protective substrate. It infested the valve after the death of the oyster made that particular piece of hard real estate available.
Interior close view 111914In the very center are some tiny encrusting cyclostome cheilostome bryozoans. Caroline, Paul and Liz Harper studied encrusting bryozoans like these from this field area as part of biogeographical and paleoecological investigation of the Cretaceous extinctions (see Sogot et al., 2013). I imagine Paul can even identify this species shown here. I wouldn’t dare! [Update from Paul: “I think these examples are cheilostomes, quite possibly Tricephalopora …” See comments.]
Thomas_Say_1818The genus Exogyra, along with the species E. costata, was named by Thomas Say (1787-1834) in 1820 (pictured above in 1818). Say was a brilliant American natural historian. Among his many accomplishments in his short career, in 1812 he helped found the Academy of Natural Sciences of Philadelphia, the oldest natural science research institution and museum in the New World. He is best known for his descriptive entomology in the new United States, becoming one of the country’s best known taxonomists. he was the zoologists on two famous expeditions led by Major Stephen Harriman Long. The first, in 1819-1820, was to the Great Plains and Rocky Mountains; the other (in 1823) was to the headwaters of the Mississippi. Along with his passion for insects, Say also studied mollusk shells, both recent and fossil. He was a bit of an ascetic, moving to the utopian socialist New Harmony Settlement in Indiana for the last eight years of his life. It is said his simple habits and refusal to earn money caused problems for his family. Say succumbed to what appeared to by typhoid fever when he was just 47.


Harris, G.D. 1896. A reprint of the paleontological writings of Thomas Say. Bulletins of American Paleontology, v. 1, number 5, 84 pp.

Say, T.G., 1820. Observations on some species of Zoophytes, shells, etc., principally fossils. American Journal of Science, 1st series, vol. 2, p. 34-45.

Sogot, C.E., Harper, E.M. and Taylor, P.D. 2013. Biogeographical and ecological patterns in bryozoans across the Cretaceous-Paleogene boundary: Implications for the phytoplankton collapse hypothesis. Geology 41, 631-634.

Wooster Geologist in Yorkshire

December 19th, 2014

1 Spaunton Quarry 121814LEEDS, ENGLAND–It was my good fortune to attend this week the 58th Annual Meeting of the Palaeontological Association in Leeds, Yorkshire, this week. I very much enjoy these meetings because of the high quality of the talks and posters, the collegiality, the field trips, and my chance to meet new colleagues and learn more about fossils and the history of life. This year I was here as a representative of the Paleontological Society and one of the Palaeontological Association’s North American Representatives. The last such meeting I attended was in Dublin in 2012.

One of the main attractions of any geological meeting are the associated field trips. Today a busload of hardy paleontologists had a field trip to the moors of northeastern Yorkshire to see Upper Jurassic limestones and fossils. The image above is from Spaunton Quarry (see below). It is no accident that this scene looks a bit stark — there was a cold wind blowing all day. Yorkshire in December is not surprisingly a bit chilly. We avoided the usual rain, though, and had a splendid day.

Betton Farm South QuarryAll our outcrops were in the Cleveland Basin, a depositional center in northeastern Yorkshire during the Late Jurassic (Oxfordian Stage). Our first stop was in the disused South Quarry at Betton Farm, where the Betton Farm Coral Bed and Malton Oolite Member is exposed (N54.25517°, W000.46503° — that cool “W000″ means we are almost on the Prime Meridian). Above you see the old quarried walls in this small excavation.

Western Face SQ 121814This is the western face of the quarry showing flat bedding of a coral-rich carbonate sand facies. To the right, out of view, is a contemporaneous coral reef (see below).

Coral Few Borings 121814This is the upper surface of the scleractinian coral Thamnasteria concinna, with a few bivalve borings (Gastrochaenolites). I would not be a happy paleontologist if I had to study these poorly-preserved corals. For contrast, you might remember the Jurassic corals of southern Israel. There’s a lot to be said for desert weathering and protective layers of marl.

BBQ 121814We had a wonderful lunchtime barbecue set up for us in the quarry. Who would guess we’d have an outdoor feast in December in northern England?

Ravenswick Quarry 121814Our second stop was at another abandoned quarry, Ravenswick (N54.25517°, W000.46500°). The Malton Oolite, which was exploited as a building stone, is exposed here. You can see the flat bedding and jointing of this rock that made it good for construction materials.

Ravenswick Rhabdophyliia phillipsiAbove the Malton Oolite is the Coral Rag Member. The branching corals shown above are Rhabdophyllia phillipsi. Since they were originally aragonitic skeletons, their later recrystallization into calcite has reduced the amount of fine detail preserved.

Sheep Spaunton 121814Our final stop was in the sheepiferous Spaunton Quarry (N54.27846°, W000.89128°). The Coralline Oolite Formation is shown above. You may again note the structural features that make this a good building stone.

Tomasz Spaunton 121814My Polish friend Tomasz Borszcz is shown above with the Coralline Oolite Formation and, immediately above, the Upper Calcareous Grit Formation. Fossils were not common here, but we did see an ammonite in the grit and some echinoid fragments in the Oolite.

Thank you very much to Dr. Crispin Little of the University of Leeds for leading this great field trip. I enjoy seeing Jurassic rocks anywhere, but they were especially attractive on the rolling moors of Yorkshire.



Wooster’s Fossils of the Week: Beautiful trace fossils from the Upper Ordovician of southern Ohio

December 19th, 2014

Trace fossils Bull Fork Ordovician OH 585Every year we highlight at least one of the fossils found and studied by Wooster’s Invertebrate Paleontology class as part of their field and laboratory exercises. This year it is this nice slab of trace fossils collected by Curtis Davies (’15) on our August 31 field trip to the emergency spillway in Caesar Creek State Park. I didn’t even notice it at the time Curtis picked it up. I only saw its full glory when he photographed the rock as part of a paleontological essay.
CurtisGalen083114aCurtis Davies is the smiling, bearded guy in the back (with Galen Schwartzberg) at the Caesar Creek outcrop. The rain had finally stopped and everyone was happy.

The traces are exposed here on the bottom of a bed of argillaceous limestone. They are preserved in what trace fossil workers (ichnologists) call convex hyporelief, which means simply that they stick out on the base (or sole) of the rock slab. These were tunnels originally excavated in soft mud by worm-like animals. The tunnels were filled with sediment that cemented up more resistant than the surrounding matrix, and thus were weathered in this relief.
Taenidium serpentinum Heer, 1877Most of the trace fossils here are the simple unlined burrow called Planolites, one of the most common traces in the Ordovician of the Cincinnati area. The trace labelled with the red “T” above, though, is rare here. Note that it is formed by a series of pulse-like movements that produced segments in the sediment infill. My estimate is that this trace can be classified as Taenidium serpentinum Heer, 1877. It is not common in the Ordovician.
Heer, Oswald, 1809-1883Oswald Heer (1809-1883), the scientist who named Taenidium serpentinum, was a Swiss geologist and botanist. As was the case for many educated Europeans, he started as a clergyman, even signing up for holy orders. The natural world captivated him, though, and starting with insects he worked his way up to become a naturalist and professor of botany at the University of Zürich. He was one of the key figures in the establishment of paleobotany (the study of fossil plants).
Taenidium serpentinum Heer, 1877 image 585Here is Heer’s figure of Taenidium serpentinum from Plate XLV in his 1877 book, Flora fossilis Helvetiae (Fossils Plants of Switzerland). You see the irony already. Heer described this trace fossil as a plant, inadvertently becoming one of the early figures in ichnology, the study of trace fossils.

Oswald Heer published many books and papers, becoming well known for his geological and paleontological explorations and descriptions. He was awarded the prestigious Wollaston Medal from the Geological Society of London in 1874. He was an earlier advocate of using fossils to sort on problems of paleogeography. He knew, for example, that Miocene fossils in Europe and North America were very similar, so he suggested in those days before Plate Tectonic Theory that the two continents were connected by a “land bridge“. This was called the “Atlantis Hypothesis”, and you can imagine the confusion that name caused among various cranks and pseudoscientists looking for Plato’s mythical continent. Heer died in Switzerland in 1883.


D’Alessandro, A. and Bromley, R.G. 1987. Meniscate trace fossils and the Muensteria-Taenidium problem. Palaeontology 30: 743-763.

Heer, O. 1877. Flora fossilis Helvetiae: Die vorweltliche flora der Schweiz. Zürich, J. Wurster & Company. 182 p.

Keighley, D.G. and Pickerill, R.K. 1994. The ichnogenus Beaconites and its distinction from Ancorichnus and Taenidium. Palaeontology 37: 305-338.

Keighley, D.G. and Pickerill, R.K. 1995. Commentary: The ichnotaxa Palaeophycus and Planolites: Historical perspectives and recommendations. Ichnos 3: 301-309.

Wooster’s Fossils of the Week: New tropical Jurassic bryozoan species from southern Israel

December 12th, 2014

1 Hyporosopora nanaWe are pleased to introduce to the world four new species of Jurassic cyclostome bryozoans. In a paper that has just appeared in the Bulletin of Geosciences, Steph Bosch (’14), Paul Taylor and I describe the first tropical Jurassic bryozoan fauna (see Wilson et al., 2015, below; it is open access and a free download). This work was the basis of Steph’s excellent Senior Independent Study thesis, and it could not have been done without Paul’s bryozoan mastery and his scanning electron microscopy skills. We found six bryozoan species in the Matmor Formation (Middle Jurassic, Callovian) exposed in Hamakhtesh Hagadol, southern Israel, four of which are new to science and shown in this post. The image above is a colony of Hyporosopora nana n. sp. attached to a crinoid ossicle.
2 Gonozooid Hyporosopora nanaIdentifying and classifying Jurassic cyclostome bryozoans almost always involves finding the specialized reproductive gonozooids. Here we see a close-up of the gonozooid on H. nana. The ooeciopore (an opening for communication with the water outside) is at the distal end on the right. The species name “nana” means “small” in Latin and refers to the small size of the autozooids (feeding zooids).
3 Hyporosopora negevensisThis is Hyporosopora negevensis n. sp., named after its type location in the Negev. On the right side of the colony you can see its characteristic boomerang-shaped gonozooid.
4 Idmonea snehiIdmonea snehi n. sp. is named after my good friend and superb geologist Amihai Sneh of the Geological Survey of Israel. Amihai has now “retired” officially after a distinguished career, but continues to work. He is the lead author of the new Geological Map of Israel. Turns out I have no images of him with his face to the camera.
5 Idmonea snehi colorThis is a color optical image of I. snehi to show what these fossils look like outside the SEM. The wiggly lines you see in the background are where the host crinoid columnals articulate in the stem. (The crinoid is Apiocrinites negevensis.) I. snehi has the earliest example of lateral branching in a post-Paleozoic cyclostome, and is now the only published example of lateral branching in any Jurassic bryozoan.
6 Microeciella yoaviMicroeciella yoavi n. sp. (above) has a gonozooid with a spherical brood chamber, visible near the center of the image. It is named after another good friend and colleague, Yoav Avni of the Geological Survey of Israel. Yoav has been my field companion for over a decade now and is most responsible for the logistical and scientific success of our expeditions into the Negev. Yoav even accompanied the Wooster Geologists on our last departmental field trip to the Mojave Desert.
7 MatmorBryoField070513Team Israel 2013 worked hard to find the bulk of the bryozoans used in this study. They are shown above at one of our most productive sites in Hamakhtesh Hagadol.
8 2013 team IsraelWe took a group photo in Jerusalem in July 2013. On the left is Steph Bosch (’14; bryozoan expert); next to her is Lizzie Reinthal (’14; crinoid specialist); then Oscar Mmari (’14; he worked on Cretaceous phosphates but also valiantly collected Jurassic bryozoans); then me; and on the far right Yoav Avni.

Please download and read the paper for more information and context on this study. The Matmor bryozoans are most similar to their counterparts in the Callovian of Poland. The low diversity of the Matmor bryozoan fauna is not unusual for the Jurassic, but they are less abundant than contemporaneous bryozoan faunas from higher paleolatitudes in Europe and North America. The unusually small zooids of the Matmor bryozoans may be a function of the “temperature-size rule” because this fauna developed in shallow, warm, tropical waters.


Ausich, W.I. and Wilson, M.A. 2012. New Tethyan Apiocrinitidae (Crinoidea, Articulata) from the Jurassic of Israel. Journal of Paleontology 86: 1051–1055.

Feldman, H.R. and Brett, C.E. 1998. Epi- and endobiontic organisms on Late Jurassic crinoid columns from the Negev Desert, Israel: Implications for co-evolution. Lethaia 31: 57–71.

Wilson, M.A., Bosch, S. and Taylor, P.D. 2015. Middle Jurassic (Callovian) cyclostome bryozoans from the Tethyan tropics (Matmor Formation, southern Israel). Bulletin of Geosciences 90: 51–63.

Wilson, M.A., Reinthal, E.A. and Ausich, W.I. 2014. Parasitism of a new apiocrinitid crinoid species from the Middle Jurassic (Callovian) of southern Israel. Journal of Paleontology 88: 1212-1221.

Zatoń, M. and Taylor, P.D. 2009. Middle Jurassic cyclostome bryozoans from the Polish Jura. Acta Palaeontologica Polonica 54: 267–288.

Wooster’s Fossils of the Week: Fish-bitten echinoid spines from the Middle Jurassic (Callovian) of southern Israel

December 5th, 2014

BittenSpine585110214This week we revisit a group of fossils covered in an earlier blog post. It is now the subject of a paper that has just appeared in the journal Lethaia entitled, “Bitten spines reveal unique evidence for fish predation on Middle Jurassic echinoids“. My co-authors are my good Polish colleagues Tomasz Borszcz and Michał Zatoń. Above is one of these bitten echinoid spines from the Matmor Formation (Callovian) of Hamakhtesh Hagadol, the Negev, southern Israel. Many Independent Study students who worked in Israel over the past several years helped me collect hundreds like it. Now we have at last sorted through them systematically, collected the data, and published our analysis as a Lethaia Focus paper.
Figure 1 110214This is Figure 1 from the paper, with the caption: Selected examples of bitten rhabdocidaroid echinoid spines from the Matmor Formation (Callovian) of Hamakhtesh Hagadol, southern Israel. All scale bars are 5 mm. All specimens are from locality C/W-370 (N 30.94952°, E 34.98725°). A-I, various flabellate spines showing bite marks. J, spine with a double tooth impression. K-L, closer views of bite marks on flabellate spines. M, closer view of spine illustrated as A showing multiple tooth marks caused by a series of teeth. (Tomasz Borszcz constructed this great composite image.)
SpineCollectionMatmor585We have here the earliest direct evidence of fish predation on echinoids (“sea urchins” in this case) through these numerous bite marks. The echinoid was a species of Rhabdocidaris, which was very spiny. As you can see in the above image, the spines are diverse in shape and size. The large, flat ones easily preserve encrusters and bite marks. We collected and assessed 1266 spines; 57 of them (4.5%) are bitten.
RhabdocidaridTestPlateA test fragment from Rhabdocidaris found with the spines. Bits of the test (the main skeleton surrounding the body) are not nearly as common as the spines. The central elevation (the boss) is where a single spine was attached.

Camelbed 110214My Israeli geologist friend Yoav Avni is here collecting echinoderm fragments from one of my favorite (if least photogenic sites). It is an area used by camels for sleeping and mucking about in the soft sediments. Their activity brings fossil fragments to the surface in a most efficient way. (Finally something positive to say about the camels in Hamakhtesh Hagadol.)

Echinoderm bits 110214Here is a collection of fossil echinoderm fragments from this site. Most are from crinoids, but I’m sure you’ve noted the two echinoid spines there.

The variability of bite marks on the spines suggests that the predator manipulated the echinoids for some period, as shown by the sheephead fish (Semicossyphus pulcher) that feeds on sea urchins today. This YouTube video (expertly filmed by Joseph See and used with permission) shows a sheephead biting and tossing about an echinoid before forcing it open. Imagine what the spines would look like that are scattered about on the seafloor. This is the scenario we imagine for our Jurassic echinoids.

Predation is an important selective force in the evolution of communities, so this first evidence of direct predation on echinoids is an important data point in the explanation of how Mesozoic invertebrate marine communities changed in structure and composition after the Permian mass extinctions. Geerat Vermeij began the modern discussion of predation’s role in evolution with his 1977 paper on the Mesozoic Marine Revolution. We’re proud to have our work in this tradition.

If you want a pdf of our new Lethaia paper, please contact me.


Borszcz, T. and Zatoń, M. 2013. The oldest record of predation on echinoids: evidence from the Middle Jurassic of Poland. Lethaia 46, 141–145.

Vermeij, G.J. 1977. The Mesozoic marine revolution; evidence from snails, predators and grazers. Paleobiology 3, 245–258.

Wilson, M.A., Borszcz, T. and Zatoń, M. 2014. Bitten spines reveal unique evidence for fish predation on Middle Jurassic echinoids. Lethaia (DOI: 10.1111/let.12110).

Wilson, M.A., Feldman, H.R., Bowen, J.C. and Avni, Y.  2008. A new equatorial, very shallow marine sclerozoan fauna from the Middle Jurassic (late Callovian) of southern Israel. Palaeogeography, Palaeoclimatology, Palaeoecology 263, 24–29.

Wilson, M.A., Feldman, H.R. and Krivicich, E.B. 2010. Bioerosion in an equatorial Middle Jurassic coral-sponge reef community (Callovian, Matmor Formation, southern Israel). Palaeogeography, Palaeoclimatology, Palaeoecology 289, 93–101.

Zatoń, M., Villier, L. and Salamon, M.A. 2007. Signs of predation in the Middle Jurassic of south-central Poland: evidence from echinoderm taphonomy. Lethaia 40, 139–151.

Wooster’s Fossils of the Week: Large Miocene barnacles with bioimmurations from Maryland

November 28th, 2014

Barnacle side viewThese two beautiful barnacles are from the Calvert Formation (Middle Miocene) exposed near Parker Creek in Maryland. They are likely of the genus Chesaconcavus. Barnacles are most unlikely crustacean arthropods, cousins of shrimp, crabs and lobsters. Most, like these above, cement themselves head-downwards on a hard substrate like a rock or shell (or boat hull), build a carapace around themselves of calcitic plates, and then filter-feed by kicking their filamentous legs in the water above to catch suspended food. They are entirely marine and usually live in shallow water.
Chesaconcavus top view 585This is a top view of the barnacle pair. We can look straight into the carapace because the opercular plates, which form a kind of door system, have been removed. For barnacles, these are a healthy large size.
Barnacle baseNow we’ve turned the barnacles upside-down to see their attachment surface. The substrate to which they were glued is gone, so we can see the details of the basal plates. The barnacles may have just sloughed off a shell or rock, or maybe they were attached to an aragonitic shell that dissolved away. What is cool here is that we can see other organisms that were on the substrate the barnacles encrusted, including two smaller barnacles completely absorbed within the larger skeletons. This is again an example of bioimmuration. The smaller barnacles look like upside-down cones in this perspective. Note that in the apex of each you can see preserved opercular plates — the insides of the “doors” that are opened for feeding. In the fine-grained skeleton of the larger attachment surface you can see growth lines made by the large barnacles as they occupied the substrate. There are even some small serpentine impressions that may represent soft-bodied organisms that were bioimmured.
Chesaconcavus base detail 585Here’s a closer view of the above basal features. I love the frilly edge of the bioimmured barnacle in the top left.


Kidwell, S.M. 1989. Stratigraphic condensation of marine transgressive records: Origin of major shell deposits in the Miocene of Maryland. Journal of Geology 97: 1-24.

Zullo, V.A. 1992. Revision of the balanid barnacle genus Concavus Newman, 1982, with the description of a new subfamily, two new genera, and eight new species. Paleontological Society Memoir 27: 1-46.

Wooster’s Fossils of the Week: A trace fossil from the Ordovician of Estonia

November 21st, 2014

Hyoliths03_585The fossils above have been in a previous post as examples of hyolith internal molds from the Middle Ordovician of northern Estonia. I collected them on my first visit to the Baltic countries in 2006. This week I want to recognize them again, but this time for the squiggly trace fossils you can just make out on their outer surfaces. These are the ichnospecies Arachnostega gastrochaenae Bertling, 1992. They are the subject of a paper that has just appeared in Palaeontologia Electronica entitled, simply enough, “The trace fossil Arachnostega in the Ordovician of Estonia (Baltica)“. The senior author is my Estonian buddy Olev Vinn. My Polish friend Michał Zatoń, my new Estonian colleague Ursula Toom, and I are co-authors.
399-861 copyAbove is an unpublished image of a gastropod internal mold from the Estonian Ordovician taken by Olev. It shows very well the variable branching nature Arachnostega. This trace was formed by a deposit-feeding organism mining organic material in a sediment-filled shell. It worked along the sediment-shell interface, probably because there was more nutrient value at that margin. The internal mold was formed when sediment filling the shell was cemented and the shell dissolved away, leaving the hard mold behind.
Screen Shot 2014-11-02 at 4.05.40 PMThis is Figure 3.1 in the new paper. Note the variation in the traces as well as the shells it inhabited. The caption as published: Arachnostega gastrochaenae Bertling in a gastropod from Haljala Regional Stage (Sandbian), Aluvere Quarry, northern Estonia. GIT 399-948-1. 2. Arachnostega gastrochaenae Bertling in a gastropod from the Kunda Regional Stage (Darriwilian), Kunda Ojaküla, northern Estonia. GIT 404-355-1. 3. Arachnostega gastrochaenae Bertling in a bivalve from the Haljala Regional Stage (Sandbian), Aluvere Quarry, northern Estonia. GIT 399-1590-1. 4. Arachnostega gastrochaenae Bertling in a bivalve from the Haljala Regional Stage (Sandbian), Aluvere Quarry, northern Estonia. GIT 399-1601-1. 5. Arachnostega gastrochaenae Bertling in a cephalopod from the Uhaku Regional Stage (Darriwilian), Püssi, northern Estonia. GIT 695-12-1.

Our paper analyzes the distribution of Arachnostega through the Ordovician of Baltica, a paleocontinent with a long history, including a collision with Avalonia (western Europe today, more or less) in the Late Ordovician. By plotting the occurrences of Arachnostega over time, we conclude that the makers of Arachnostega likely preferred cool climates and bivalve shells over gastropods. The tracemakers may have also been negatively influenced by the many biotic changes associated with the Great Ordovician Biodiversification Event.

Please check out the article itself. As with all papers in Palaeontologia Electronica, it is open access.


Bertling, M. 1992. Arachnostega n. ichnog. – burrowing traces in internal moulds of boring bivalves (late Jurassic, northern Germany). Paläontologische Zeitschrift 66: 177-185.

Vinn, O., Wilson, M.A., Zatoń, M. and Toom, U. 2014. The trace fossil Arachnostega in the Ordovician of Estonia (Baltica). Palaeontologia Electronica 17, Issue 3; 41A; 9 p.

Wooster’s Fossils of the Week: A new crinoid species from the Middle Jurassic of southern Israel (with a bonus parasitic infection)

November 14th, 2014

1 PitBelowCalyxThese fossils are a joy to present this week. Lizzie Reinthal (’14), Bill Ausich (Ohio State University) and I have a new paper out in the latest issue of the Journal of Paleontology. It is titled: “Parasitism of a new apiocrinitid crinoid species from the Middle Jurassic (Callovian) of southern Israel”. Allow me to introduce Apiocrinites feldmani, a new articulate crinoid species. In the image above we have fused columnals (the “buttons” that make up a crinoid stem) upwards through two radial plates (from the calyx) with two pits and associated swollen columnals (due to a nasty little parasite; see below). A gnarly beast it is, and that’s what makes this creature interesting. I posted another even more twisted specimen earlier.

This new species is named after my friend Howard Feldman of Touro College and the American Museum of Natural History in New York. He was a pathfinder with the Matmor Formation and its fossils in Hamakhtesh Hagadol, Negev, southern Israel.
2 Extracted holdfast 2Apiocrinites feldmani is a small crinoid that lived in a brachiopod-coral-sponge community with a larger cousin named Apiocrinites negevensis (named earlier by Bill Ausich and me). Above we see a pluricolumnal (range of articulated columnals) with the holdfast of another A. feldmani wrapped around them. (I’m also showing off my mad skills at extracting an image from its background.)
3 Gnarly pluricolumnalThis pluricolumnal shows how bad the parasitic infection could get for many A. feldmani specimens. These gall-like growths are responses to some soft-bodied parasite that became embedded within the crinoid skeleton. The crinoid stems were deformed and likely lost considerable flexibility because of these parasites.
4 PitThis is a cross-section through one of the pits in an A. feldmani stem. Note that the narrow end of the pit begins at the articulation between two columnals. The parasite apparently wedged into that space, forcing the crinoid to grow around it as it grew itself. The result was a conical pit with swollen columnals surrounding it.
5 PitPluricolumnalHere we’re looking straight into one of the conical pits with a magnificent swelling around it. You can barely make out the articulation lines of the swollen columnals. Sometimes these cone-shaped pits were closed off by crinoid skeletal growth, presumably because the parasite inside died or otherwise left the premises. We don’t know the identity of this parasite, but we can surmise that it was a soft-bodied filter-feeder that probably gained an advantage from living high above the seafloor on these crinoid stems. Oddly, the larger A. negevensis crinoids in the same community did not have these parasites.

Living crinoids are afflicted by a variety of parasites. There are none today that have this sort of effect on the stems, but there are reports of fossil crinoids with similar pathologies all the way back to the Silurian (Brett, 1978).
6 BivalveBoringCrinoidEven after death these Jurassic crinoid stems provided homes for other organisms. Above is another cross-section through a stem of A. feldmani. “A” is one of the columnals, “B” is a section through an articulated bivalve filled with a relatively coarse sediment, and “C” is a fine sediment that filled in around the bivalve. The bivalve bored into the crinoid stem after death to make a crypt from which it could conduct its filter-feeding with some safety and seclusion.
7 Apiocrinites feldmani specimens 585Finally, here are the type specimens of Apiocrinites feldmani all packed up to be delivered to the Orton Geological Museum at Ohio State University. This museum has a large collection of echinoderms from around the world and so is an appropriate place for our treasures to reside awaiting further study.

This was a fun study that was part of Lizzie Reinthal’s 2013-2014 Independent Study project at Wooster. She concentrated on the taphonomy and sclerobiont successions as we both worked up the parasite and systematic story with our echinoderm expert friend Bill Ausich. There aren’t that many accounts of parasite-host relationships in the fossil record, so we’re proud to add one.

So many beautiful fossils in the Jurassic of southern Israel. More papers to come!


Ausich, W.I. and Wilson, M.A. 2012. New Tethyan Apiocrinitidae (Crinoidea, Articulata) from the Jurassic of Israel. Journal of Paleontology 86: 1051–1055.

Brett, C.E. 1978. Host-specific pit-forming epizoans on Silurian crinoids. Lethaia 11: 217–232.

Feldman, H.R. and Brett, C.E. 1998. Epi- and endobiontic organisms on Late Jurassic crinoid columns from the Negev Desert, Israel: Implications for co-evolution. Lethaia 31: 57–71.

Wilson, M.A., Feldman, H.R. and Krivicich, E.B. 2010. Bioerosion in an equatorial Middle Jurassic coral-sponge reef community (Callovian, Matmor Formation, southern Israel). Palaeogeography, Palaeoclimatology, Palaeoecology 289: 93–101.

Wilson, M.A., Reinthal, E.A. and Ausich, W.I. 2014. Parasitism of a new apiocrinitid crinoid species from the Middle Jurassic (Callovian) of southern Israel. Journal of Paleontology 88: 1212-1221.

« Prev - Next »