Wooster’s Fossil of the Week: A geopetal structure in a boring from the Middle Jurassic of Israel

June 15th, 2014

Geopetal Structure 585We have a very simple trace and body fossil combination this week that provides a stratigraphic and structural geologic tool. Above is a bit of scleractinian coral from the Matmor Formation (Middle Jurassic, Callovian) of Makhtesh Gadol in southern Israel. The coral skeleton was originally made of aragonite. It has been since recrystallized into a coarse sparry calcite, so we can no longer see the internal skeletal details of the coral. In the middle of this polished cross-section is an elliptical hole. This is a boring made by a bivalve (the trace fossil Gastrochaenolites). Inside the boring you see a separate elliptical object: a cross-section of a bivalve shell. This could be the bivalve that made the boring or, more likely, a bivalve that later occupied the boring for a living refuge. This, then, is the trace fossil (Gastrochaenolites) and body fossil (the bivalve shell) juxtaposition.

That stratigraphic and structural interest is that the boring and the bivalve shell are partially filled with a yellow sediment. This sediment has gravitationally settled to the bottom of these cavities (at slightly different levels). These holes have thus acted as natural builders’ levels showing is which way was down and which was up at the time of deposition. We can tell without any clues from the recrystallized coral the “way up” before any later structural deformation (or in this case rolling around on the outcrop) changed the orientation of the coral. Pretty cool and simple, eh? The name for this feature is a geopetal structure. There are some faulted and folded sedimentary rock exposures in the world where we search diligently for these little clues to original orientation (see, for example, Klompmaker et al., 2013). Not all geopetal structures have fossil origins (i.e., Mozhen et al., 2010), but most do. A little gift from paleontology to its sister disciplines.


Klompmaker, A.A., Ortiz, J.D. and Wells, N.A. 2013. How to explain a decapod crustacean diversity hotspot in a mid-Cretaceous coral reef. Palaeogeography, Palaeoclimatology, Palaeoecology 374: 256-273.
Mozhen, G., Chuanjiang, W., Guohui, Y., Xueqiang, S., Guohua, Z. and Xin, W. 2010. Features, origin and geological significance of geopetal structures in Carboniferous volcanic rocks in Niudong Block, Santanghu Basin. Marine Origin Petroleum Geology 3: 15.
Wieczorek, J. 1979. Geopetal structures as indicators of top and bottom. Annales de la Societé géologique de Pologne 49: 215-221.

Wooster’s Fossil of the Week: My favorite part of a crinoid (Middle Jurassic of Israel)

June 1st, 2014

Apiocrinites negevensis proximale 585In April of this year I completed my 11th trip to southern Israel for fieldwork in the Mesozoic. My heart warmed every time I saw these robust plates of the crinoid Apiocrinities negevensis, which was reviewed in a previous blog post. They are thick disks of calcite with a heft and symmetry like exotic coins. They are easy to spot in the field because of their size and incised perfect star. They have been a critical part of our paleoecological and systematic studies of the Matmor Formation (Callovian, Middle Jurassic) in the Negev. Lizzie Reinthal (14) and Steph Bosch (14) know them particularly well!
negevensis proximales 1This part of the crinoid is called the proximale. It has a round base that articulates with the columnal below it in the stem, and its top has five facets that hold the basal plates of the calyx. It is thus the topmost columnal, specialized to serve as the integration between the articulated stem below and the complicated head above. The pentastellate (five-armed star, but you probably figured that out) impression is called the areola. In the very center is the open hole of the lumen, which goes from the head all the way down through the stem to the holdfast as an internal fluid-filled cavity.
Composite Miller Apiocrinites arrowedAbove are Miller’s (1821) original illustrations of Apiocrinites rotundus with the proximale shown by the red arrow. Note how thin this piece is compared to the equivalent from Apiocrinites negevensis. The significant thickness of the proximale is one of the distinguishing features of the Negev species.

I saw many more of these beautiful fossils in the field this year. We don’t need any more for our research, but they always indicate that other good fossils are nearby.


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

Miller, J.S. 1821. A natural history of the Crinoidea or lily-shaped animals, with observation on the genera Asterias, Euryale, Comatula, and Marsupites. Bryan & Co, Bristol, 150 pp.

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.

Wooster’s Fossils of the Week: “Star-rock” crinoids from the Middle Jurassic of Utah

May 18th, 2014

Isocrinus_nicoleti_Encrinite_Mt_Carmel_585This little slab of crinoid stem fragments comes from the Co-op Creek Member of the Carmel Formation (Middle Jurassic) exposed in northwestern Kane County, Utah. I collected it with my friend Carol Tang as we explored a beautiful encrinite (a rock dominated by crinoid skeletal debris) exposed near Mount Carmel Junction. In 2000, Carol and her colleagues published a description and analysis of this unit and its characteristic crinoid, Isocrinus nicoleti (Desor, 1845). This piece sits on a shelf in my office because it is so ethereal with its star-shaped columnals (stem sections). In fact, the local people in the area collect pieces of the encrinite and sell them as “star rocks“. As I recall, some folks were rather territorial about the outcrops!

Isocrinus nicoleti is one of only three crinoid species known in the Jurassic of North America. (The others are I. wyomingensis and Seirocrinus subangularis.) Tang et al. (2000) showed that this species migrated into southwestern North America by moving southward through a very narrow seaway for thousands of kilometers. I. nicoleti had long stems and relatively small crowns, so it left us zillions of the columnals and very few calices. These washed into large subtidal dunes creating the cross-bedded encrinite.
Isocrinus asteriaThe genus Isocrinus is still alive, most notably in the deep waters around Barbados in the Caribbean. Above is a diagram of Isocrinus asteria originally published by Jean-Étienne Guettard in 1761. The long stem is star-shaped in cross-section.
Pierre Jean Edouard DesorThis gentleman is Professor Pierre Jean Édouard Desor (1811-1882), who named Isocrinus nicoleti in 1845. He is shown here 20 years later. Desor was a German-Swiss geologist who studied two very disparate subjects: glaciers and Jurassic echinoderms. He trained as a lawyer in Germany, but got caught up in the democratic German unity movement of 1832-1833 and had to flee to Paris. In 1837 he met Louis Agassiz and began to collaborate with him on a variety of projects paleontological and glaciological. He even had a trip to the United States where he helped survey the coast of Lake Superior. He took a position as professor of geology at the academy of Neuchâtel, Switzerland, in 1852, eventually retiring in genteel affluence. (This is not how these geological biographies usually end!)


Ausich, W.I. 1997. Regional encrinites: a vanished lithofacies. In: Brett, C.E. and Baird, G.C. (eds.): Paleontological Events, p. 509-519. Columbia University Press, New York.

Baumiller, T.K., Llewellyn, G., Messing, C.G. and Ausich, W.I. 1995. Taphonomy of isocrinid stalks: influence of decay and autotomy. Palaios 10: 87-95.

Desor, É. 1845 Résumé de ses études sur les crinoides fossilies de la Suisse. Bulletin de la Societe Neuchateloise des Sciences Naturelles 1: 211-222.

Hall, R.L. 1991. Seirocrinus subangularis (Miller, 1821), a Pliensbachian (Lower Jurassic) crinoid from the Fernie Formation, Alberta, Canada. Journal of Paleontology 65: 300-307.

Peterson, F. 1994. Sand dunes, sabkhas, streams, and shallow seas: Jurassic paleogeography in the southern part of the western interior basin. In: Caputo, M.V., Peterson, J.A. and Franczyk, K.J. (eds.): Mesozoic Systems of the Rocky Mountain Region, USA, p. 233-272. Rocky Mountain Section-SEPM, Denver, Colorado.

Tang, C.M., Bottjer, D.J. and Simms, M.J. 2000. Stalked crinoids from a Jurassic tidal deposit in western North America. Lethaia 33: 46-54.

Wooster’s Fossil of the Week: One sick crinoid from the Middle Jurassic of Israel

May 11th, 2014

IsocrinidAMy first thought on seeing this distorted fossil was how much it evoked one of those Palaeolithic “Venus figurines“. It is certainly difficult to deduce that this is actually a crinoid column (or stem). It was found during my last expedition to the Middle Jurassic Matmor Formation in Makhtesh Gadol, southern Israel (location C/W-506). This particular crinoid was infected by parasites that caused the grotesque swellings of the skeletal calcite in the individual columnals (button-like sections of the column). The infection of a species of Apiocrinites in the Matmor is the subject of a paper now in press by me, Lizzie Reinthal (’14) and the pride of Ohio State University, Dr. Bill Ausich. That story will be a later Fossil of the Week entry. The specimen above, though, is different. To my surprise, it is a parasitic infection in an entirely different crinoid order.

IsocrinidBHere’s another view of the crinoid column. The top third shows some of the original star-shaped columnals in side view. This tells us that the crinoid was an isocrinid, possibly the cosmopolitan Isocrinus nicoleti. This group contains the famous and somewhat creepy crawling crinoids. We have just a handful of isocrinid stem fragments in the Matmor despite a decade of searching for a distinctive calyx (the head of the little beast). Note that the gall-like swellings have holes in them. This will be important in a later analysis of the parasitic system here.

IsocrinidCAnd now the other side of the fossil. Again, in the top part you can make out star-shaped columnals, but that distinctive outline is lost in the swollen column below. The stem must have been seriously hindered from flexing and bending with such a debilitating infection.


Salamon, M.A. 2008. The Callovian (Middle Jurassic) crinoids from northern Lithuania. Paläontologische Zeitschrift 82: 269-278.

Tang, C.M., Bottjer, D.J. and Simms, M.J. 2000. Stalked crinoids from a Jurassic tidal deposit in western North America. Lethaia 33: 46-54.

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 (in press).

Last work of Team Israel, Matmor Division

May 5th, 2014

Team Israel 050514WOOSTER, OHIO–Steph Bosch (’14) and Lizzie Reinthal (’14) volunteered to examine the Matmor Formation fossils I collected last month in Israel. Each fossil, most of which are crinoid ossicles, must be scanned under a microscope for tiny encrusters (especially bryozoans), borings, and bite marks. In the image above you can see the collection bags on the left and our three ‘scopes arranged so that we can exchange interesting bits that we find. I had planned to do this work all by my lonesome, and it would have taken a full day. With Steph and Lizzie, though, we were done in an hour and a half. No wonder — they’ve spent the last year doing this kind of analysis!

Israel specimens 050514And here are the results. Each paper tray has a particular category of fossil from a specific location. We found many little (and I mean little) treasures that my future students and I can now study. I’m grateful for the expert help.

Team Israel 2013 will be graduated a week from today. Congratulations to them!

Wooster’s Fossils of the Week: A scleractinian coral and its tube-dwelling symbionts (Middle Jurassic of Israel)

April 20th, 2014

MatmorCoral010114aI have a weakness for the beautiful scleractinian corals of the Matmor Formation (Middle Jurassic, Callovian-Oxfordian) of southern Israel. This particular specimen is Microsolena aff. M. sadeki from locality C/W-367 in Hamakhtesh Hagadol, southern Israel. (The “aff.” in the name means “affinities with”. It is a way of saying this looks like a particular species, but we’re not quite sure.) This is a place we’ve now had ten Wooster Team Israel expeditions, the latest of which was last summer. The corals are a prominent part of the very diverse fossil fauna there. Note in the above side view of the specimen the star-shaped corallites (which held individual polyps) each with radiating septa. In the middle of the view you can see a narrow tube covered by coral skeleton. (More on this below.)
MatmorCoral010114bThis is a top view of the coral. It has a generally flat base and an upper surface with extended knobs. Usually this particular species is flat across the top as well as the base, giving it a platter shape as in this previous Fossil of the Week.
MatmorCoral010114cFlip the coral over and we see how it is preserved. The skeleton was originally made of the mineral aragonite, which dissolved after the death and burial of the colony. The resulting void was filled with stable calcite, preserving even fine details of the septa (see below). This delicate preservation, though, is only of the exterior of the skeleton. The interior is coarsely crystalline calcite with no trace of internal coral structures. This preservation, then, is properly called a cast, not true replacement.
MatmorCoral010114tubeThese scleractinian corals had many symbionts (organisms that lived with them). Among them were tube-dwelling worms, probably polychaetes, that spread across the surface. We know this happened while the coral was alive because, as seen above, the septa sometimes grew over the tubes. The tubes themselves are here preserved in three dimensions because they are originally calcitic and did not dissolve after death and burial.

We have much to learn about these gorgeous Jurassic fossil corals of Israel. They are virtually unstudied and offer a great opportunity for comparing them to the global Jurassic coral world.


Martin-Garin, B., Lathuilière, B. and Geister, J. 2012. The shifting biogeography of reef corals during the Oxfordian (Late Jurassic). A climatic control?. Palaeogeography, Palaeoclimatology, Palaeoecology 366: 136-153.

Pandey, D.K., Ahmad, F. and Fürsich, F.T. 2000. Middle Jurassic scleractinian corals from northwestern Jordan. Beringeria 27: 3-29.

Reolid, M., Molina, J.M., Löser, H., Navarro, V. and Ruiz-Ortiz, P.A. 2009. Coral biostromes of the Middle Jurassic from the Subbetic (Betic Cordillera, southern Spain): Facies, coral taxonomy, taphonomy, and palaeoecology. Facies 55: 575-593.

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.

Return to the Jurassic Paradise of Makhtesh Gadol

April 15th, 2014

Makhtesh Gadol 041514MITZPE RAMON, ISRAEL–This week I’m back in Makhtesh Gadol, that great bowl of Jurassic delights. This is the most extensive exposure of marine Jurassic rocks in southern Israel, and it is highly fossiliferous. This is just a brief report. I’ll summarize the latest finds and ideas later.

Greened 608 041514Today I spent most my time sitting on these low outcrops at a place we affectionately call “GPS 004 C/W-608″. It is the most productive site for crinoids and their associated sclerobionts (organisms that lived on or in their skeletons, before or after death). There was something about the original distribution of these organisms, and then the preservation and landscape erosion, that makes this site so good. Today I was not disappointed.

MatmorCollectView070513Compare this view of the site in July last year with Oscar Mmari, Steph Bosch and Lizzie Reinthal (all Wooster seniors now). The winter and spring rains were a bit higher than normal in this part of the country, so the outcrop today looks positively overgrown! This picture makes me miss having my students along on this trip, but such are research leaves.

Wooster Geologists at the North American Paleontological Convention in Florida

February 16th, 2014

Lizzie & Steph 021514GAINESVILLE, FLORIDA–Steph Bosch (’14), Lizzie Reinthal (’14) and I flew out of icy Ohio this weekend to attend the 10th North American Paleontological Convention in warm, sunny northern Florida. The students jointly presented the beautiful poster above on their Independent Study projects in the Matmor Formation (Middle Jurassic, Callovian) of southern Israel. It was very well received, especially with the addition of fantastic scanning electron microscope images of bryozoans produced by our colleague Paul Taylor at the Natural History Museum in London.

Crowd scene 021514Here’s a crowd scene from the first poster session at NAPC. If you look closely in the center, you’ll see two Wooster alumnae who are prominent paleontologists. Can’t swing a cat at a paleo meeting without hitting Wooster Geologists.

Hilton 021514This is a nondescript image of our hotel and convention center in Gainesville. I show it only to marvel in the blue, blue sky and perfect temperatures. We are on the University of Florida campus near the Florida Museum of Natural History. The paleontology staff at that museum is sponsoring this meeting — and they are doing an extraordinary job made more complex by the absence of about a third of the participants still snow-bound in the north. We escaped through a window of clear weather in Ohio.

Wooster’s Fossil of the Week: A long scleractinian coral from the Middle Jurassic of Israel

November 17th, 2013

Enallhelia_370_Callovian_Israel_585Just one image for this week’s fossil, but we make up for the numbers in image length! The above fossil with the alternating “saw teeth” is the scleractinian coral Enallhelia d’Orbigny, 1849. It is a rare component of the diverse coral fauna found in the Matmor Formation (Callovian-Oxfordian) in southern Israel. I collected this particular specimen (from locality C/W-370 in Hamakhtesh Hagadol, for the record) during this past summer’s expedition to the Negev. It is preserved remarkably well considering that its original aragonite skeleton has been completely calcitized.

Enallhelia is in the Family Stylinidae, also named by French naturalist Alcide Charles Victor Marie Dessalines d’Orbigny. (Love that name; he was briefly profiled in a previous entry.) There are many species in the genus (at least two dozen), but I can’t figure out which this one is. I’ll need a coral expert because half of the available species look pretty much the same to me. Enallhelia is a dendroid coral, meaning its corallum has tree-like branches, only one of which we see here. Each branch has alternating corallites on each side, which in life would have held the individual tentacular polyps. Each corallite has radial symmetry, not the usual hexameral symmetry as seen in most scleractinians. The genus ranges from the Jurassic into the Cretaceous and is cosmopolitan. Enallhelia is especially well known from Europe, but that may be just a collector effect.

What I like about Enallhelia is that it can be an excellent paleoenvironmental marker. Leinfelder and Nose (1997) show that it is most often found in “marly coral meadows” near storm wavebase on carbonate platforms. This means it is in shallow but quiet waters well within the photic zone most of the time, but may be occasionally disturbed by storm wave currents. This is an accurate description of most of the depositional environment of the Matmor Formation.


Hudson, R.G.S. 1958. The upper Jurassic faunas of southern Israel. Geological Magazine 95: 415-425.

Leinfelder, R.R. and Nose, M. 1997. Upper Jurassic coral communities within siliciclastic settings (Lusitanian Basin, Portugal): Implications for symbiotic and nutrient strategies. Proceedings of the 8th International Coral Reef Symposium 2: 1755-1760.

Olivier, N., Martin-Garin, B., Colombié, C., Cornée, J.-J., Giraud, F., Schnyder, J., Kabbachi, B. and Ezaidi, K. 2012. Ecological succession evidence in an Upper Jurassic coral reef system (Izwarn section, High Atlas, Morocco). Geobios 45: 555-572.

Wooster paleontologists present at the Geological Society of America meeting in Denver

October 28th, 2013

Lizzie102813DENVER, COLORADO–Yesterday Oscar Mmari (’14) gave the first presentation from Wooster’s Team Israel 2013 at the annual meeting of the Geological Society of America in Denver. Today our two paleontologists on the team discussed their posters.

Above is Lizzie Reinthal (’14) cheerfully giving her poster entitled: “Taphonomic feedback and facilitated succession in a Middle Jurassic shallow marine crinoid community (Matmor Formation, southern Israel)“. Her work is co-authored with our friend Howie Feldman. Below Steph Bosch (’14) is ready to discuss her work: “First bryozoan fauna described from the Jurassic tropics: Specimens from the Matmor Formation (Middle Jurassic, Upper Callovian) in southern Israel“. Steph’s poster has the famous palaeontologist Paul Taylor as a co-author.

Steph102813It is great fun to see these students make the transition, both intellectually and physically, from the scorched desert floor of the Negev to such a professional setting. The faculty are very proud.


« Prev - Next »