Wooster’s Fossil of the Week: A bivalve boring from the Upper Ordovician of southern Ohio

Mark Wilson December 16, 2012 1:35 am

This week’s fossil is from close to home. In fact, it sit in my office. The above is a trace fossil named Petroxestes pera. It was produced on a carbonate hardground by a mytilacean bivalve known as Modiolopsis (shown below). Apparently the clam rocked back and forth on this substrate to make a small trench to hold it in place for its filter-feeding. This particular specimen of Petroxestes was found in the Liberty Formation (Upper Ordovician) of Caesar Creek State Park in southern Ohio. This is a place many Wooster paleontology students know well from field trips.
The original Petroxestes was at first known only from the Cincinnatian Group, but now it is known from many other places and time intervals, even including the Cretaceous and Miocene. It is a good lesson about trace fossils. They are defined by their morphology, not what organisms made them. It turns out that this slot-shaped trace can be made by other animals besides Modiolopsis, which went extinct in the Permian.

References:

Jagt, J.W.M., Neumann, C. and Donovan, S.K. 2009. Petroxestes altera, a new bioerosional trace fossil from the upper Maastrichtian (Cretaceous) of northeast Belgium. Bulletin de l’Institut royal des Sciences naturelles de Belgique, Sciences de la Terre 79: 137-145.

Pickerill, R.K., Donovan, S.K. and Portell, R.W. 2001. The bioerosional ichnofossil Petroxestes pera Wilson and Palmer from the Middle Miocene of Carriacou, Lesser Antilles. Caribbean Journal of Science 37: 130-131.

Pojeta Jr., J. and Palmer, T.J. 1976. The origin of rock boring in mytilacean pelecypods. Alcheringa 1: 167-179.

Tapanila, L. and Copper, P. 2002. Endolithic trace fossils in Ordovician-Silurian corals and stromatoporoids, Anticosti Island, eastern Canada. Acta Geologica Hispanica 37: 15–20.

Wilson, M.A. and Palmer, T.J. 1988. Nomenclature of a bivalve boring from the Upper Ordovician of the midwestern United States. Journal of Paleontology 62: 306-308.

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

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Wooster Geologist in Ireland

Mark Wilson December 15, 2012 7:28 am

IrishFlag121512DUBLIN, IRELAND — In a very quick transition from grading final exams in Wooster yesterday morning, I find myself now in downtown Dublin. I flew in last night to attend the 56th Annual Meeting of the Paleontological Association. I’ve been a member of this wonderful organization since 1985 — in fact, I’m one of the North American Representatives — and I love my rare visits to the main meetings. They are held throughout Europe to recognize the international base of the Palaeontological Association, with an emphasis on its European core. I am here representing the Paleontological Society in my role as Secretary. I am looking forward to meetings with my paleontologist colleagues, and to learning more about our craft and passion.

DublinPostOffice121512Since my first meeting is tomorrow morning, I spent some time looking at some of the historical places in the Dublin City Centre. Most impressive to me is the evocative Post Office, site of the failed Easter Rising by Irish nationalists in 1916. Above is the post office today. Below is the burned-out shell after the 1916 battle with British troops. Bullet scars are still visible in the stonework.

Dublin_Post_Office_1916

FourCourts121512The Four Courts, Ireland’s main court complex. The original structure was built in the 18th Century. The River Liffey is in the foreground.

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Wooster’s Fossil of the Week: A horn coral from the Upper Ordovician of Indiana

Mark Wilson December 9, 2012 1:34 am

This week’s fossil is a very common one from the Whitewater Formation (Richmondian, Upper Ordovician) exposed near Richmond, Indiana. It was collected, along with hundreds of other specimens, during one of many Invertebrate Paleontology field trips to an outcrop along a highway. The fossil is Grewingkia canadensis (Billings, 1862), a species my students know well because many made acetate peels of cross-sections they cut through it.

Grewingkia canadensis belongs to the Order Rugosa, a group commonly called the “horn corals” because their solitary forms (as above) have a horn-like shape. Children often think they are dinosaur teeth! It is so common in Richmondian rocks that it is sometimes used to indicate current direction. Its robust skeleton provided attachment space to many encrusting organisms, and it often has multiple borings in its thick calcite theca.

We believe that the rugose corals lived much like corals today. They sat partially buried in the sediment with the wide end of the skeleton facing upwards. A polyp sat inside the cup-shaped opening, spreading its tentacles to catch small organisms swimming by.

Grewingkia canadensis has a complicated taxonomic history. It is likely also known as Streptelasma rusticum, Grewingkia rustica, Streptelasma vagans, Streptelasma insolitum, and Streptelasma dispandum. G. canadensis is characterized by cardinal and counter septa (the vertical partitions inside the coral skeleton) that are longer than the other major septa throughout ontogeny (growth).
The handsome man shown above is, of course, a paleontologist. This is Elkanah Billings (1820-1876), Canada’s first government paleontologist and the one who named Grewingkia canadensis. (He originally placed it in the genus Zaphrentis.) Billings was born on a farm near Ottawa. He went to law school and became a lawyer in 1845. But he loved fossils and in 1852 founded a journal called the Canadian Naturalist (and Geologist). In 1856, Billings left the law and joined the Geological Survey of Canada as its first paleontologist. He named over a thousand new species in his career, and is best known for describing the first fossil from the Ediacaran biota — a critical time in life’s early history. The Billings Medal is given annually by the Geological Association of Canada to the most outstanding of its paleontologists.

References:

Billings, E. 1862. New species of fossils from different parts of the Lower, Middle, and Upper Silurian rocks of Canada. Paleozoic Fossils, Volume 1, Canadian Geological Survey, p. 96-168.

Elias, R.J. and Lee, D.J. 1993. Microborings and growth in Late Ordovician halysitids and other corals. Journal of Paleontology 67: 922-934.

Elias, R.J., McAuley, R.J. and Mattison, B.W. 1987. Directional orientations of solitary rugose corals. Canadian Journal of Earth Sciences 24: 806-812.

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Familiar Faces at AGU 2012

mpollock December 3, 2012 7:57 pm

San Francisco, CA – The annual meeting of the American Geophysical Union is the largest earth science conference in the world.

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With more than 20,000 attendees and about 3000 posters per day, you’re bound to bump into someone you know. Today, I ran into Wooster alum Jesse Davenport (’11). You may remember his senior I.S. adventures in Montana, working on 2 billion year old sheared igneous and metamorphic rocks. Jesse is currently a graduate student at Notre Dame and has shifted his focus to more recent (~80 million years old) basalts – a topic that I can finally relate to!

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Jesse is studying the compositions and textures of plagioclase and olivine crystals in basalts from the Detroit Seamount to better understand magmatic processes at ocean islands. (See a more complete explanation in his AGU abstract). It’s always fun to catch up with alumni who travel diverse paths yet have the common Wooster experience. If we’re lucky, Jesse will come to Wooster to share his research and experiences with GeoClub sometime this spring.

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Wooster’s Fossils of the Week: Shark teeth! (Upper Cretaceous of Israel)

Mark Wilson December 2, 2012 1:37 am

This week’s set of exquisite fossils is presented in honor of Andrew Retzler (’11) who has just had his Senior Independent Study thesis at Wooster published in the journal Cretaceous Research: “Chondrichthyans from the Menuha Formation (Late Cretaceous: Santonian–Early Campanian) of the Makhtesh Ramon region, southern Israel“. The above beauties are a mix of Scapanorhynchus teeth found in the southwestern portion of Makhtesh Ramon during Andrew’s study in the summer of 2010. We were ably assisted by Micah Risacher and Yoav Avni with these collections.

Andrew identified at least eight shark species and two other fish species in the Menuha Formation around Makhtesh Ramon. Most of the teeth are from a soft yellowish chalk with relatively few other fossils (mostly oysters, echinoids, foraminiferans and traces). They show that the Menuha was deposited in a shallow, open-shelf environment on the flanks of the developing Ramon anticline. So, they not only provide new information about Cretaceous sharks in the Middle East, they help sort out a complex stratigraphic-structural problem.

Well done, Andrew! (Andrew is currently a graduate student at Idaho State University. He is working on the Late Devonian Alamo Impact Event in Nevada with Dr. Leif Tapanila.)

Tooth of the shark Cretalamna appendiculata. Composite photo by Andrew Retzler.

Scapanorhynchus rapax, another shark species. Composite photo by Andrew Retzler.

An elegant Scapanorhynchus texana tooth.

Looking south at one of the productive exposures of the Menuha Formation (shown as the red dot) at Makhtesh Ramon. This is one of those amazing Google Earth images.

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Geology Heads to Melrose Elementary

sjudge November 29, 2012 5:24 pm

WOOSTER, OHIO — A “Volcano Team” headed to Melrose Elementary this week for an afternoon of fun with Marge Forbush’s 4th grade class. It was our annual fall trip to her classroom, and our task was to discuss the various geologic processes associated with volcanoes. The 4th grade students had already studied plate tectonics and volcanoes, so they were experts on the volcabulary, such as “Ring of Fire”, “magma chamber”, and “Pompeii”. Before Thanksgiving, they had even built active volcanoes in the classroom.

Our goal was to bring pounds and pounds of volcanic rock to show the students, so that they could see basalt, volcanic bombs, obsidian, pumice, tuff, and several intrusive rocks (granite and gabbro). Wooster students in the department each were in charge of specific stations around the classroom, and the 4th graders migrated between stations. Here’s a look at some of our Wooster students hard at work:

Lauren Vargo (’13) is a Wooster veteran of community outreach, having gone with both Greg Wiles and myself to several elementary schools in Wooster (Cornerstone, Melrose, and formerly Wayne).  She was in charge of discussing the impact of contact metamorphism with the students, and she had numerous metamorphic rocks on hand.

Matt Peppers (’13) seemed to field some of the most unusual questions of the day.  Here he is showing the 4th graders several different types of intrusive igneous rocks, along with the minerals in each rock.  Some of the students in Matt’s group are destined to become geologists, because they already could identify the minerals from their own “rock collections” at home.

Adam Silverstein (’16) was in charge of one of the more fun stations:  volcanic bombs!!  He used some of his knowledge from Meagen Pollock’s Natural Hazards course in order to talk to the students about hazards during a volcanic eruption.  As you can imagine, everyone liked to pick up the volcanic bombs, some of which were collected in the Black Rock Desert, Utah.

Another member of Wooster’s Natural Hazards course, Kaitlin Starr (’16), was a welcomed volunteer and an old friend.  Kaitlin, who was in charge of the lava flow station, is a Wooster native.  Kaitlin was actually a student of Marge Forbush when she was in the 4th grade, and so she received a round of applause from the students for coming back and visiting her old classroom.

We’ll be back to visit Marge’s classroom again in the spring, but next time our focus will be on fossils.  Stay tuned!!

 

 

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Wooster’s Fossil of the Week: A gumdrop bryozoan (Middle Ordovician of eastern Iowa)

Mark Wilson November 25, 2012 1:03 am

This simple, rounded fossil with tiny holes on its surface is the trepostome bryozoan Prasopora falesi (James, 1884) from the Middle Ordovician Galena Group of eastern Iowa. It was collected with dozens of others on an Independent Study field trip in 2003 with Aaron House (2004). Aaron was studying the paleoecology of these bryozoans; he was especially interested in borings in these calcitic bryozoans called Trypanites.

Part of Aaron’s project involved cutting through these Prasopora colonies to see the borings on the inside. He made acetate peels of polished slabs of the bryozoans, a technique that produces a detailed acetate replica of internal details.
The image above is of one of those acetate peels. You can see the tubular zooecia that contained the original zooids (or individuals) of the bryozoan colony. (They are a series of ellipses because of the angle of the cut and variations in zooecial growth directions.) The black dots are very curious: they are apparently brown bodies, the fossilized remains of the tiny polypides inside the zooecia. These organic remains were replaced by dark minerals and preserved all these 470 million years since.

References:

Anstey, R.L. and Perry, T.G. 1972. Eden Shale bryozoans: a numerical study (Ordovician, Ohio Valley). Michigan State University Publications of the Museum, Paleontological Series, Vol. 1, 80 p.

James, U.P. 1884. Descriptions of four new species of fossils from the Cincinnati Group. The Journal of the Cincinnati Society of Natural History 7: 137-140.

Morrison, S.J. and Anstey, R.L. 1979. Ultrastructure and composition of brown bodies in some Ordovician trepostome bryozoans. Journal of Paleontology 53: 943-949.

Nicholson, H.A. and Etheridge, R., Jr. 1877. On Prasopora Grayae, a new genus and species of Silurian corals. Annals and Magazine of Natural History 4:388–392.

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Wooster’s Fossil of the Week: A crab from the Pleistocene of northern Australia

Mark Wilson November 18, 2012 1:32 am

Isn’t this amazing preservation? This fossil crab, which we received as a donation a few years ago, is Macrophthalmus latreillei (Desmarest, 1822) from the Pleistocene of northern Australia. It is virtually identical to its modern counterpart of the same species, Latreille’s Sentinel Crab.

M. latreillei has large, stalked eyes. It likes to hide under a layer of sand with its eyes sticking out looking for predators. It is mostly active in the night, burrowing through the sediment collecting deposited organic material. It is found throughout the Indo-Pacific region.

The modern crab species M. latreillei was named in 1822 by the French zoologist Anselme Gaëtan Desmarest (1784–1838), shown above. He was a student of two other famous French scientists: Georges Cuvier and Alexandre Brongniart. He was the Professor of Zoology at the École nationale vétérinaire d’Alfort, succeeding the zoologist Pierre André Latreille (1762-1833), for whom he named this crab.
Latreille (above) was a most interesting fellow. He was an entomologist and a specialist in crustaceans. In 1786, when he was 24 years old, he was ordained a priest. This turned out, in hindsight, to be an almost fatal mistake. He was arrested by French revolutionaries in 1794 on suspicion of being a counter-revolutionary monarchist cleric (which he likely was). He was sentenced to deportation to a miserable tropical island prison. Just before he was scheduled to be shipped away, his jailers found him carefully studying a beetle crawling across his grungy cell floor. The authorities thought he had gone crazy in prison, but Latreille announced that the insect was a very rare species. This got back to an expert who confirmed the beetle as Necrobia ruficollis. Other experts then intervened to rescue the perceptive Latreille from prison and a tropical grave. To this day an image of this beetle is engraved on Latreille’s tombstone in Paris. Taxonomy saved a life.

References:

Barnes, R.S.K. 1967. The Macrophthalminae of Australia, with a review of the evolution and morphological diversity of the type genus Macrophthalmus (Crustacea: Brachyura). Transactions of the Zoological Society of London 31: 195-262.

Dupuis, C. 1974. Pierre André Latreille  (1762-1833): the foremost entomologist of his time. Annual Review of Entomology 1974: 1-13.

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Wooster Geologists on Camera — Spotlight on Dendrochronology

Mark Wilson November 16, 2012 11:49 am

WOOSTER, OHIO–Greg Wiles and members of his crack dendrochronology team from our tree-ring laboratory are being filmed today for a PBS program called “Our Ohio“. It is great fun watching the TV crew setting up their equipment, and our faculty, staff and students getting ready for their close-ups. We thought you might like to see a few pictures of the process. In the image above you see Greg thoughtfully listening to instructions from the field producer.

Here’s a closer view of the camera set-up, including a small monitor that shows exactly what the camera sees.

Jenn Horton (’13), looking stylish and Wooster-branded, is talking to the film crew as they set up the dendrochronology lab with lights. Tree-ring lab veterans know this room well! (I think it looks a little cleaner than usual.)

Greg Wiles and our ace technician Nick Wiesenberg at one of the dendrochronology stations prior to filming. Nick had just dated a particular barn in question as having been built in — spoiler alert! — 1845. A preliminary date, Greg quickly adds.

The TV crew van parked outside Scovel Hall this morning, greatly enhancing our departmental prestige on campus. (Everyone knows, after all, they didn’t come here to interview philosophers.)

We hope to have more photos later of the outdoor filming. Well done, Wooster dendrochronologists!

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Wooster’s Fossil of the Week: A new crinoid species from the Middle Jurassic of southern Israel

Mark Wilson November 11, 2012 1:29 am

About a year ago I showed my good friend Bill Ausich (The Ohio State University) hundreds of crinoid pieces from the Matmor Formation (Jurassic, Callovian) exposed in Hamakhtesh Hagadol, southern Israel. We knew the crinoid represented by all these pieces belonged to the genus Apiocrinites Miller, 1821, but we could not place the species. Bill, crinoid genius that he is, then figured out this was a new species. We now have the pleasure of introducing Apiocrinites negevensis Ausich & Wilson, 2012.

This species of Apiocrinites, the first described from Jurassic tropical latitudes, is distinguished by features in its calyx (or crown or head). A. negevensis has a narrow radial facet and adjacent arms are not in lateral contact. It also has large aboral cup plates. (And it is gorgeous.) In the above image from Figure 1 of our paper, the A. negevensis holotype is shown as 1-3; 1 is a lateral view, radial plate missing from either side of the single preserved radial plate; 2, radial facet; 3, inside of cup with cavity extending to proximale; 4, a partial cup with proximale, one complete and one broken basal plates, and one broken radial plate (note numerous barnacle borings, Rogerella Saint-Seine, 1951, on this specimen).

A holdfast of Apiocrinites negevensis that was attached to the underside of a coral. (From Figure 1 of Ausich and Wilson, 2012.)

Apiocrinites negevensis parts in the  field (Matmor Formation, Hamakhtesh Hagadol, southern Israel). See this post for a discussion of our fieldwork.

The taxonomic category we know as the Crinoidea was established in 1821 by J.S. Miller, who separated the stalked echinoderms from all the others. At the same time he erected the genus Apiocrinites.

Cover of Miller’s 1821 book describing the crinoids, including the new Apiocrinites.

Miller’s (1821) illustrations of Apiocrinites.

References:

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.

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.

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

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