Archive for May, 2014

Wooster’s Fossil of the Week: A fly in amber

May 25th, 2014

Fly in amber 012614A classic fossil this week. I wish I could say more about it. The specimen lost its label years ago, so I don’t know where it is from or its age (although a good guess is Neogene). I also can’t identify it with my skill set beyond “fly” (Order Diptera). Beautiful, though. The images were not easy to make. I used our photomicroscope and played with a combination of light from below (transmitted) and above (reflected). The polished amber fragment is about the size of a pea and the fly is near the middle of it.
Fly legs in amber 012614A closer view here of the legs. Each segment can be seen, along with their tiny spines. This seems to be a particularly long-legged fly.

Preservation in amber is a well known phenomenon. An insect like ours gets itself trapped in a drop of tree resin. The resin hardens into amber by losing much of its volatile content with heat over time. Polish the piece and you can peer inside and see the occasional treasures of three-dimensionally preserved organisms. Oddly enough, in most cases these fossils are hollow external molds with no internal tissues preserved. What we see is the outside of this cavity with pigments embedded in the amber. (This fly has gorgeous red eyes, for example.) Remember the Jurassic Park premise that dinosaur DNA had been recovered from blood in a mosquito’s belly preserved in Dominican amber? It just doesn’t happen. In fact, a recent study (Penney et al., 2013) showed that insect DNA doesn’t even survive in sub-fossil assemblages.

I know from experience that it is very easy to be fooled by fake amber. As a policy, I’ve learned to not buy it in an Estonian open market (just as an example!). After Jurassic Park appeared, the demand for amber shot up, especially if it had animals in it. Artificial amber, and amber made from shavings and fragments (“pressed amber”) flooded the market. Caveat emptor. I tested our piece and it passed.

For more images of insects in amber, please follow the link or just search “amber”.

References:

Penney, D. 2002. Paleoecology of Dominican amber preservation: spider (Araneae) inclusions demonstrate a bias for active, trunk-dwelling faunas. Paleobiology 28: 389-398.

Penney, D., Wadsworth, C., Fox, G., Kennedy, S.L., Preziosi, R.F. and Brown, T.A. 2013. Absence of ancient DNA in sub-fossil insect inclusions preserved in ‘Anthropocene’ Colombian copal. PloS one 8(9), e73150. DOI: 10.1371/journal.pone.0073150

Poinar Jr, G.O. 1993. Insects in amber. Annual Review of Entomology 38: 145-159.

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!)

References:

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.

References:

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 Fossil of the Week: A scolecodont from the Upper Ordovician of the Cincinnati region

May 4th, 2014

Cincinnatian scolecodontThis tiny but fearsome jaw is known as a scolecodont, and they are fairly common in the Cincinnatian rocks (Upper Ordovician) in the tri-state area of Ohio, Kentucky and Indiana. The label on this particular specimen does not indicate the exact locality or stratigraphic unit, but it does give a taxonomic name: “Nereidavus varians Grinnell 1877″. More on that below.

Scolecodonts are the jaws of extinct polychaete annelid worms. They are known from the Cambrian right through the Recent, so we’re pretty sure what their functions were: grabbing prey and pulling it into the gullet of the worm. They are made of a very tough chitin (an organic material much like our fingernails) and survive well the vicissitudes of fossilization. I ran across them often when I studied conodonts, which they superficially resemble.

Polychaete mouthThe Telegraph, of all places, has some amazing SEM images of the scary end of living jawed polychaetes, one of which is shown above. (I think they colored it to look like it has blood on its teeth.) Our Ordovician jaw easily fits into this functional model.

For much more on scolecodonts, Olle Hints has a superb website devoted just to these critters, and Rich Fuchs has a very useful page on the Cincinnatian varieties.

Now as for the name of our specimen, it appears that the taxonomy of Ordovician scolecodonts is in a bit of disarray. Nereidavus Grinnell, 1877, is, according to Bergman (1991) and Eriksson (1999), a nomen dubium (dubious name) because the holotype (single primary type specimen) of the type species is lost. That specimen was from Cincinnatian strata, then referred to as “Lower Silurian”. The paratype (sort of a spare type specimen) is N. varians, the same name on the label of our specimen. Eriksson considered that species to be in the genus Ramphoprion Kielan-Jaworowska, 1962. A true diagnosis of our specimen would involve extracting it from the matrix and looking at it its dorsal (oral) surface, but that’s not going to happen. I’m plenty happy just leaving this fossil as Ramphoprion sp.

Kielan-JaworowskaThe paleontologist who named the scolecodont genus Ramphoprion is the famous and incredibly accomplished Zofia Kielan-Jaworowska (above). She is best known for her pioneering work on dinosaur-bearing deposits in Mongolia in the 1960s, but she has worked on many fossil groups from trilobites to mammals. Kielan-Jaworowska (born in 1925) received her Masters Degree in zoology and a doctorate in paleontology (aren’t many of those now) at Warsaw University. She became a professor there and was later the first woman to serve on the executive committee of the International Union of Geological Sciences. I read her 1974 book Hunting for Dinosaurs in college as an adventure tale with a strong narrative framework of science. It was inspirational, and it convinced me that paleontology was the coolest science.

References:

Bergman, C F. 1991. Revision of some Silurian paulinitid scolecodonts from western New York. Journal of Paleontology 65: 248–254.

Eriksson, M. 1999. Taxonomic discussion of the scolecodont genera Nereidavus Grinnell, 1877, and Protarabellites Stauffer, 1933 (Annelida: Polychaeta). Journal of Paleontology 73: 403-406.

Eriksson, M. and Bergman, C.F. 2003. Late Ordovician jawed polychaete faunas of the type Cincinnatian Region, U.S.A. Journal of Paleontology 77: 509-523.

Grinnell, G.B. 1877. Notice of a new genus of annelids from the Lower Silurian. American Journal of Science and Arts 14: 229–230.

Hints, O. and Eriksson, M.E. 2007. Diversification and biogeography of scolecodont-bearing polychaetes in the Ordovician. Palaeogeography, Palaeoclimatology, Palaeoecology 245: 95-114.

Kielan-Jaworowska, Z. 1962. New Ordovician genera of polychaete jaw apparatuses. Acta Palaeontologica Polonica 7: 291-325.