Wooster’s Fossil of the Week: A shrimp from the Upper Jurassic of Bavaria, Germany

June 2nd, 2013

Aeger_tipularis_SolnhofenThe beautiful fossil shrimp above is Aeger tipularis (Schlotheim, 1822), and it comes from one of the most famous rock units: the Solnhofen Plattenkalk (Tithonian, Upper Jurassic) of Germany. (The Solnhofen is well known for its extraordinary fossils, including the fossil bird Archaeopteryx.) This shrimp is yet another generous gift to the Department of Geology from George Chambers (’79).

The shrimp in the Solnhofen are very well preserved. Note the long, long antennae and the tiny spines on the carapace. (I suspect, though, that parts of this specimen have been enhanced with ink by a commercial collector, especially the legs.)

SchlotheimFigure051813

Aeger tipularis was described in 1822 by Ernst Friedrich, Baron von Schlotheim (1764-1832), a prolific German paleontologist we profiled earlier. The drawing above is the original reconstruction by Schlotheim (1822, pl. 2, fig. 1; Solnhofen Lithographic Limestone, Solnhofen area; Lower Tithonian, Hybonotum Zone; width of figure 23.7 cm.)

References:

Garassino, A. and Teruzzi, G. 1990. The genus Aeger MÜNSTER, 1839 in the Sinemurian of Osteno in Lombardy (Crustacea, Decapoda). Atti della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano 131: 105-136.

Schlotheim, E.F. von. 1822. Nachträge zur Petrefactenkunde (Addenda al Petrefactenkunde). Gotha, Beckersche Buchhandlung.

Schweigert, G. 2001. The late Jurassic decapod species Aeger tipularius (Schlotheim, 1822) (Crustacea: Decapoda: Aegeridae). Stuttgarter Beiträge zur Naturkunde, Series B, 309: 1-10.

Wooster’s Fossil of the Week: An amphibian from the Permian of Germany

May 19th, 2013

Apateon_pedestris_Odernhelm_Germany_fixedThe above skeleton is of the salamander-like Apateon pedestris von Meyer 1840 from the Lower Permian of Odernhelm, Germany. There are just enough of these tiny little bones to show the ghostly outline of this freshwater amphibian. It is our only amphibian fossil at Wooster, and it is another gift from the George Chambers collection.

Apateon pedestris is in the Order Temnospondyli, a group thought to be ancestral to the modern salamanders. They would have lived much like their descendants today, spending most of their time in creeks and streams and wet leaf litter. It grew to a maximum length of about nine centimeters. Its head was wide and flat, presumably to aid in swimming. Some specimens are preserved with soft tissues intact showing that this species had external gills as an adult, a classic example of paedomorphosis (as my History of Life students will tell you).

homo diluvii testis-1The skull of our tiny specimen reminds me of a younger, larger and much more famous Miocene amphibian that went for a time under the surprising name Homo diluvii testis, meaning “evidence of a human at the time of the Noah’s Flood”. A drawing of the skeleton is shown above.

Johann Jacob Scheuchzer (1672-1733)

Johann Jakob Scheuchzer (above) described and interpreted Homo diluvii testis in Lithographia Helvetica (1726). He was convinced it represented a person (more likely a child) who was drowned in the Flood of Noah and then entombed in the sediments. The critical page from his book is shown below.

HdtJohann Jacob Scheuchzer (1672-1733) was a Swiss medical doctor and somewhat of a naturalist. He certainly had a gift for seeing a human pattern in these bones that is lost on us today — the skeleton is obviously not that of any kind of mammal. It is likely he was far too enthusiastic about finding what he considered solid proof of the Flood and a member of the wicked generation nearly killed off by it. Here is a bit of poetry he included in his fossil description:

Afflicted skeleton of old, doomed to damnation,
Soften, thou stone, the heart of this wicked generation!

homo diluvii testis

Much later the famous French scientist Georges Cuvier (1769-1832) had at Scheuchzer’s fossil (above). He showed that it was, of course, an amphibian. The name for it now is Andrias scheuchzeri — a perpetual honor for its sincere but deluded discoverer.

References:

Fröbisch, N.B., Carroll, R.L. and Schoch, R.R. 2007. Limb ossification in the Paleozoic branchiosaurid Apateon (Temnospondyli) and the early evolution of preaxial dominance in tetrapod limb development. Evolution and Development 9: 69-75.

Fröbisch, N.B. and Schoch, R.R. 2009. The largest specimen of Apateon and the life history pathway of neoteny in the Paleozoic temnospondyl family Branchiosauridae. Fossil Record 12: 83-90.

Wooster’s Fossil of the Week: A brittle star from the Upper Jurassic of Germany

March 10th, 2013

Ophiopetra lithographica aboral larger 010813_585Wooster geologists have again greatly benefited from the donation of a collection by an alumnus. George Chambers (’79), a successful professional photographer, sent us several boxes of minerals, rocks and fossils he had acquired in his lifelong passion for geology. (George was a geology major at Wooster in the class just after mine.) Among the many world-class specimens he gave us are two fossil ophiuroids (brittle stars). They are Ophiopetra lithographica Enay and Hess, 1962, from the Lower Hienheim Beds (Lower Tithonian, Upper Jurassic) near Regensburg, Germany. They are part of the “Fossillagerstätte Hienheim“, a preserved brittle star ecosystem in a lagoon at the edge of a Late Jurassic sea. This is the same set of lithographic limestones in which the famous bird fossil Archaeopteryx was found.
Ophiopetra lithographica 010813_585In both these images you see the spiny arms of the brittle stars twisted about. It is their flexibility and snake-like movements in life that provoked the scientific name ophiuroids (serpent-forms) for the brittle stars. The “brittle” term comes from their ability to autotomize (spontaneously detach) their arms when threatened, leaving a squirming distraction for a predator as they escape.
Ophiopetra lithographica aboral 010813_585Ophiopetra lithographica is probably the most common fossil brittle star known. It was preserved by the countless millions in these Jurassic lagoons in Germany. Most geologists believe they were buried by fine-grained carbonate sediment suspended by sudden storms. As you can see in the above close-up, the preservation of the plates and spines is remarkable.

Most brittle stars are suspension feeders (sorting out food particles from the water), deposit feeders (eating organic material in the sediment) or scavengers. Ophiopetra lithographica may have been a carnivore with its heavily-spined arms and strong jaws. It likely ate small arthropods on the seafloor.

The evolution of brittle stars is interesting and controversial. They were relatively common in the Paleozoic and then just barely survived the Permian extinctions. Their rapid evolution into a variety of taxa in the Mesozoic and Cenozoic has led to many debates about their phylogeny. Even the placement of Ophiopetra into a family is a problem. Does it belong to the Family Aplocomidae where it was originally placed or to the older Family Ophiolepididae as has been recently suggested?

Our students will enjoy these fine fossils in the invertebrate paleontology course. They have doubled our collection of brittle stars! Thank you again to George Chambers for his thoughtfulness and generosity.

References:

Enay, R. and Hess, H. 1962. Sur la découvertes d’Ophiures (Ophiopetra lithographica n.g. n.sp.) dans le Jurassique supérieur du Haut-Valromey (Jura méridional). Eclogae geologicae Helvetiae 55: 657-678.

Hess, H. and Meyer, C.A. 2008. A new ophiuroid (Geocoma schoentalensis sp. nov.) from the Middle Jurassic of northeastern Switzerland and remarks on the Family Aplocomidae Hess 1965. Swiss Journal of Geosciences 101: 29-40.

Röper, M. and Rothgänger, M. 1998. Die Plattenkalke von Hienheim (Landkreis Kelheim) – Echinodermen-Biotope im Südfränkischen Jura. Eichendorf (Eichendorf Verlag), 110 S.

Stöhr, S. 2012. Ophiuroid (Echinodermata) systematics—where do we come from, where do we stand and where should we go? In: Kroh, A. and Reich, M. (Eds.) Echinoderm Research 2010: Proceedings of the Seventh European Conference on Echinoderms, Göttingen, Germany, 2–9 October 2010. Zoosymposia, 7: 147-161.

Thuy, B., Klompmaker, A.A. and Jagt, J.W.M. 2012. Late Triassic (Rhaetian) ophiuroids from Winterswijk, the Netherlands; with comments on the systematic position of Aplocoma (Echinodermata, Ophiolepididae). In: Kroh, A. and Reich, M. (Eds.) Echinoderm Research 2010: Proceedings of the Seventh European Conference on Echinoderms, Göttingen, Germany, 2–9 October 2010. Zoosymposia, 7: 163-172.

Last stop in Europe: The Senckenberg Museum of Natural History

August 18th, 2010

FRANKFURT, GERMANY–Isn’t that a great front yard for a Natural History Museum? Diplodocus longus strides by columnar basalt and a massive chunk of conglomerate. This is the Naturmuseum Senckenberg in downtown Frankfurt, about two blocks from my hotel. On my last day in Europe I met with Dr. Mena Schemm-Gregory, a brilliant young paleontologist who specializes in brachiopods. I was very impressed with the labor-intensive way by which she makes three-dimensional reconstructions of brachiopods embedded in matrix, including their internal structures. I also simply enjoyed the museum displays. This is a good way to end this eventful trip — a visual survey of the history of life!

The front of the Senckenberg Museum, which was built in the first decade of the 20th Century. The tall object on the left is a life-sized reconstruction of a Carboniferous seedless vascular plant. I'm cleverly using it to hide an annoying smokestack in the background!

Close-up of a massive piece of Banded Iron Formation also standing outside the museum. This one is anywhere from 3.5 to 1.9 billion years old. It represents a complex interaction of ancient microbes, seawater and the atmosphere which is still not completely understood.

Even the living plants highlight life's history. This is a branch of a ginkgo tree, a group which has an ancient lineage extending back to the Triassic. Er ist ein "Lebendes Fossil".

The Messel Fossil Pit: A world-class experience

August 13th, 2010

FRANKFURT, GERMANY–Last year at this time I had the privilege of visiting the Middle Cambrian Burgess Shale on an expedition led by my friend Matthew James of Sonoma State University in California. It was an extraordinary opportunity to visit one of the most important fossil sites in history. Today our IBA field trip had a tour of another UN World Heritage fossil locality: the Messel Pit near Darmstadt, Germany. These Eocene oil shales were formed under very unusual conditions. They are maar deposits formed in a volcanic crater. Catastrophic releases of poisonous gases, the hypothesis goes, occasionally killed the surrounding fauna, causing many to tumble into the anoxic lake to be preserved in amazing detail. This is the home of Ida (Darwinius masillae), the controversial primate fossil now in Oslo (which I also saw last summer).

Our field party was taken down into the center of the maar to an excavation site run by the Senckenberg Museum in Frankfurt. There we watched a team of paleontologists excavate blocks of the shale and examine them for fossils.

Paleontologists extracting large blocks of Messel oil shale to examine for fossils.

Close-up of the Messel Shale. It contains about 40% water in outcrop, and so dries quickly in the sun. Fossils must be kept wet until preserved by various chemicals.

One of the paleontologists splitting Messel Shale with a large knife. The waste pile of examined pieces is behind her. Note the spray bottle of water beside her chair. The fossils must be kept from drying out until they are preserved.

Bits of an Eocene bird found in the Messel Shale while we were visiting.

An artesian well in the center of the Messel structure made when geologists drilled over 400 meters into the shales below. Yes, the tradition is to drink a glass of the water! (And I did.)

An outcrop of the Messel Oil Shale near the eastern side of the pit.

With this memorable paleontological experience our International Bryozoology Association field trip ended. I am grateful to Priska Schäfer of Kiel University for the fantastic (and complicated) organization and leadership. My teaching and research has been greatly enhanced, and I made wonderful new friends as well.

Tunnels yet again — and a loess connection

August 13th, 2010

OPPENHEIM, GERMANY–This jewel of a town, with its large cathedral, half-timbered buildings and narrow streets, share surprising geological connections with Vicksburg, Mississippi — a city visited by Wooster geologists earlier this summer. Both are river towns which profited in good times as trade centers, and both are underlain by Pleistocene loess sediments. Loess is wind-deposited silt and clay that can be easily excavated yet retain vertical walls because of the angular nature of its grains. Residents of both cities dug caverns into their loess deposits to store goods and to escape the dogs of war above them.

Model of a family hiding in a loess cavern underneath Oppenheim, Germany.

Oppenheim is almost completely undermined by up to 200 km of connected tunnels and cellars known collectively as the Kellarlabyrinth. The digging began sometime in the Middle Ages as a way to safely store and transport goods between buildings in the prosperous town. When the religious wars of the 17th century began, Oppenheim was almost continually besieged and occupied by one side or the other. The labyrinth below became a good place to hide from marauding soldiers. The system continually grew as the Oppenheimers dug laterally through the thick bed of loess below their town. The tunnels are still in partial use today after renovation and structural enhancement. In 1945 the American Army successfully crossed the Rhine near Oppenheim. As one of General George Patton’s tanks moved through the streets of Oppenheim, it crashed through the street into a tunnel below. Heavy vehicles have been rerouted around Oppenheim ever since!

You can't have an extensive Medieval cavern system in Continental Europe without some part of it turned into an ossuary. There are the remains of at least 20,000 people in the Oppenheim bone caverns.

A rainy day in the Mainz Basin

August 12th, 2010

View of the vineyards near Wöllstein, Germany.

View of the vineyards near Wöllstein, Germany.

OPPENHEIM, GERMANY–I want this termed Wilson’s Law: “The amount of mud encountered at an outcrop is inversely proportional to the quality of the fossils found.” Maybe it is my desert heritage, but I absolutely detest mud on my boots. Especially deep sticky quarry mud that grips lug soles and builds a progressively larger glob with every step. I try very hard to avoid slogs through it, but I’ve been spectacularly unable to avoid it in some places. Far too often I’ve slipped and slid through the glutinous stuff to find the rocks at the end to be distinctly unfossiliferous. Well mudded for little reward. Such was the case at the Rüssingen Limestone Quarry pictured below:

Today was a wet one in the Mainz Basin, and my fossil bag remained relatively empty except for some mollusk shells with borings (many of which are well described on this amateur’s page). Still, the geology was very interesting. The Mainz Basin is not a true basin in the geological sense. It is better described as a fracture zone at the western border of the Upper Rhine Graben. We were most interested in the shallow marine and brackish water Oligocene sediments deposited within these boundaries. Some of the sediments rested directly on sea cliffs of Permian rhyolite which was spectacular (but alas, not photogenic).

Clasts in the Alzey Formation (Oligocene, Rupelian) exposed near Wöllstein, Germany. The large pebble by the two-Euro coin is a Permian rhyolite; the white pebbles are from quartz veins in metamorphic rock. Both clast types were derived from nearby rocky cliffs during deposition.

Our last stop of the day was the Naturhistorisches Museum Mainz (Mainz Natural History Museum). This was much fun, especially since we had a special dinner with the director and staff in the galleries. The collection and displays are very good. I could have the usual photo of some vertebrate fossil in a case, but instead I was taken with a humble drawer of fossil snails packed in cotton so that they appeared to be floating in clouds:

Wooster Geologist on the Rhine

August 11th, 2010

OPPENHEIM, GERMANY–Our International Bryozoology Association field trip started the day in the little town of Prüm looking at Devonian limestones and shales, and then we drove to Boppard where we boarded a Rhine River ferry for a trip upstream to Bacharach. The weather threatened rain but held off, giving us excellent views of the steep sides of the middle Rhine Valley with its little villages, precipitous vineyards, and numerous castles.

One of the attractions of this voyage was the “Loreley“, a large cliff at the narrowest point of the Rhine. It has historically been the site of many accidents because of the shallow, fast waters over the rocky river bed near the outcrop. There is a thick crust of Germanic sentimentality over this place which I don’t quite understand. In our case it involved the ferry loudspeakers playing a song based on a poem by Heinrich Heine that is a traditional favorite. At least I know this: the rock is a Lower Devonian quartzite, part of the Taunus Formation, and derived from tidal flat sediments!

The Loreley exposure on the right bank of the Rhine River, Germany.

The power of biostratigraphy: the Campanian-Maastrichtian boundary in the Late Cretaceous

August 7th, 2010

Chalk quarry I visited today near Lägerdorf, Germany. It is Late Cretaceous in age, spanning the Campanian-Maastrichtian stage boundary. Location: N53.90395°, E9.57840°.

Outcrop of the Pierre Shale in South Dakota visited two years ago by a Wooster Geology team. It is also Late Cretaceous and at the Campanian-Maastrichtian stage boundary.

KIEL, GERMANY–Comparing the two very different geological sections pictured above, you should ask how we know that they are precisely the same age. After all, they are thousands of miles apart and are quite different in their composition and fossil content. We can even say that the boundary between the Campanian and Maastrichtian stages (these are fine divisions of geological time) is 70.6 million years old, give or take a hundred thousand years or so. The answer starts with the belemnite fossil Belemnella lanceolata, a nice example of which we found today in the German chalk quarry:

A belemnite is an extinct cephalopod (a group which includes the modern squid, octopus and others) that is a common fossil in Mesozoic sediments, especially in the Jurassic and Cretaceous Periods. They were swimming predators and so they could live happily in oceanic and shelf waters with little regard for the sediments beneath them. They are thus found in a variety of sedimentary rocks around the world. Belemnella lanceolata is present throughout Europe in a narrow time interval bounded by its origination and extinction. It overlaps in its age range with a variety of other fossils in a chain of co-occurrences that eventually includes Baculites baculus of South Dakota. Because these fossil species evolved and went extinct at specific times, correlation links them together through a particular time interval. Geologists decided that the first appearance of Belemnella lanceolata would be the marker for the base of the Maastrichtian Stage (and by implication the top of the Campanian Stage). Thus we use paleontology and evolution to mark time in the rock record and correlate these time units around the world. For more details on this story you can check out the massive Late Cretaceous correlation chart (a colorful pdf) hosted by Purdue University.

How do we know this boundary is 70.6 million years old, more or less? That is another story of volcanic ash falls, igneous rocks, and radioactive dating. Maybe later!

International Bryozoology Association meeting ends, field trips begin

August 6th, 2010

KIEL, GERMANY–The 15th meeting of the International Bryozoology Association ended this afternoon with the usual giving of awards, assessing the budget, and planning the next meeting (Sicily in 2013). I like this group very much. It is the best combination of biologists and paleontologists I know. (A larger version of the official photograph by Andrej Ernst is available.)  The field trips begin tomorrow!

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