Grès à Voltzia: Mid-Triassic French Lagerstätten

In our last post*, we got our first glimpse of some of the flora and fauna that inhabited the earth 240 MYA, in the Mid Triassic Period.  In that post, we mostly looked at the aquatic environments, fossils found at a fascinating place in Italy called Monte san Giorgio.  In good time, we will learn more about the terrestrial ecosystems and what lived on land.  But first, let us look between the aquatic and the terrestrial.  Let's look at the seashores of this ancient Earth.

To gain a better understanding of what lived on the margins of the oceans, we can look at Grès à Voltzia in France.  The importance of this site lies not just in the preservation of a large number of different organisms, but in the exceptional quality of said preservation.  Grès à Voltzia is considered a Lagerstätte, a German word referring to fossil sites that feature remarkable detail in the preservation of fossils, with famous examples including the Solnhofen Limestone in Germany and the Green River Formation in Wyoming.  The depositional environment that would one day become Grès à Voltzia featured deltas very close to the shore, and were home to many animals.  This prime habitat resulted in the burial of both terrestrial and marine animals, painting an even more complete picture of this ecosystem.

Here we have a picture lifted from my Instagram that shows three very different animals from the aforementioned Lagerstätten. What ties these three animals is their common ability to fly.  On the right, we have pictures of two fossil casts from the Solnhofen Limestone in Germany, deposited about 150 MYA.  Archaeopteryx, the primitive bird/dinosaur link, is on top, and Pterodactylus, a type of pterosaur, is on the bottom.  The picture on the right is of a bat from the Eocene of Wyoming, found in the Green River Formation, deposited approximately 50 MYA.  Despite its age, Icaronycteris was fairly similar to modern bats.  All three of these animals convergently evolved flight, and were not derived from a common ancestor.

Along the shores of these 240 MY old rivers, horsetails and and ferns grew in abundance, as well as several different types of gymnosperms.  Large amphibians such as Eocyclotosaurus made their home in these waterways, as they were tied to moist environments just like modern amphibians are today.

Horseshoe crabs like Limulitella, very similar to modern horseshoe crabs, are commonly found, as are many types of crustaceans, such as Antrimpos, a type of shrimp.

Insect larvae includes dipteran (true flies), odonatopteran (dragonflies and damselflies) and ephemeropteran (mayflies).  Annelids (segmented worms like the modern earthworm) have also been discovered here, as well as fish and a jellyfish.

The horsetails, such as Equisetites, grew along the edges of the water, while the gymnosperms grew further inland, probably reaching at least several meters in height.

A large number of insects, including the dipterans and ephemeropterans that we already mentioned, lived here.  Proto-cockroaches (blattopterans), beetles (coleopterans), and hemipteroids were all present, as well as myriapods (centipedes and millipedes), and spiders.  A strange mixture of modern and exotic looking animals to be certain!

Next time, we will be continuing our investigation regarding the flora and fauna of the Mid Triassic by learning about two North American geologic formations that might reveal a bit more about the terrestrial ecosystems.  Join us!

*As those of you who are familiar with myself and this blog, you are likely familiar with the fact that once I start talking, it takes a good deal to make me shut up.  The same is true for writing this blog.  When I originally came up with the idea to do a post about the flora and fauna that inhabited the Earth 240 MYA, flora and fauna that many people, myself included, are relatively unfamiliar with, it was supposed to be a relatively short post, maybe four or five paragraphs in length.  Instead, I ended up just writing and writing and writing.  I realized, as I often do, that A) so few people would be reading these posts to begin with, and B) those people who do wind up reading these posts would likely not have stuck around for an immense post that talks about everything from the ichthyosaurs of Italy, the stromatolites of Colorado, the insects of France, the communal latrines of Tasmanian devils, the lack of communal latrines of Maiasaura, the communal latrines of dicynodonts (yes, poop is cool), the heterodont condition of primitive whales, and everything in between, that it made more sense to split the post up.  This is the second installment of five (so far, at least) regarding the flora and fauna of the Mid Triassic Period, approximately 240 MYA.  It now occurs to me that I probably lost most of you in this long-winded exposition.  I don't want to just delete all this though, as future generations will find this fascinating glimpse into my thought processes an untapped reservoir of knowledge that is absolutely vital to an understanding of the ultimate being I shall become.  I think I will just make this whole thing an endnote.

Works Cited:



Bottjer, D. J. (2002). Exceptional Fossil Preservation: A Unique View on the Evolution of Marine Life. New York: Columbia University Press.

Braithwaite, C. J., & Zedef, V. Hydromagnesite Stromatolites and Sediments in an Alkaline Lake, Salda Golu, Turkey. Journal of Sedimentary Research, 66. Retrieved June 20, 2014, from http://jsedres.geoscienceworld.org/content/66/5/991.abstract

Carroll, R. L. (1988). Vertebrate paleontology and evolution. New York, N.Y.: W.H. Freeman and Company.

Fiorelli, Lucas E., Martín D. Ezcurra, E. Martín Hechenleitner, Eloisa Argañaraz, Jeremías R. A. Taborda, M. Jimena Trotteyn, M. Belén Von Baczko, and Julia B. Desojo. The oldest known communal latrines provide evidence of gregarism in Triassic megaherbivores. Scientific Reports. Retrieved June 21, 2014, from http://www.nature.com/srep/2013/131128/srep03348/full/srep03348.html#ref8

Hammer, WR., 1990: Thrinaxodon from Graphite Peak, central Transantarctic Mountains, Antarctica. Antarctic Journal of the United States, 255: 37-38

Lautenschlager, S., & Desojo, J. B. Reassessment of the Middle Triassic Rauisuchian Archosaurs Ticinosuchus ferox and Stagonosuchus nyassicus. Paläontologische Zeitschrift. Retrieved June 20, 2014, from http://www.researchgate.net/publication/225706328_Reassessment_of_the_Middle_Triassic_rauisuchian_archosaurs_Ticinosuchus_ferox_and_Stagonosuchus_nyassicus

Mickelson, D. L. (2014, June 6). Triassic Tracks in the Moenkopi Formation. National Parks Service. Retrieved June 20, 2014, from http://www.nps.gov/care/naturescience/triassictrack.htm

Morales, M. Terrestrial Fauna and Flora from the Triassic Moenkopi Formation of the Southwestern United States. Journal of the Arizona-Nevada Academy of Science, 22. Retrieved June 20, 2014, from http://www.jstor.org/discover/10.2307/40024380?uid=3739568&uid=2&uid=4&uid=3739256&sid=21104182410797

Nesbitt, S. J. Arizonasaurus and Its Implications for Archosaur Divergence. Biological Sciences, 270. Retrieved June 20, 2014, from http://rspb.royalsocietypublishing.org/content/270/Suppl_2/S234.abstract

Nesbitt, S. J. Osteology of the Middle Triassic Pseudosuchian Archosaur Arizonasaurus babbitti. Historical Biology: An International Journal of Paleobiology, 17. Retrieved June 20, 2014, from http://www.tandfonline.com/doi/abs/10.1080/08912960500476499#.U6Ti2ZRdV1-

Nesbitt, S. J., Barrett, P. M., Werning, S., Sidor, C. A., & Charig, A. J. The Oldest Dinosaur? A Middle Triassic Dinosauriform from Tanzania. Biology Letters, 9. Retrieved June 20, 2014, from http://rsbl.royalsocietypublishing.org/content/9/1/20120949.abstract

Owen, D., & Pemberton, D. (2005). Tasmanian devil: a unique and threatened animal. Crows Nest, N.S.W.: Allen & Unwin.

Power, I. M., S. A. Wilson, G. M. Dipple, and G. Southam. Modern carbonate microbialites from an asbestos open pit pond, Yukon, Canada. Geobiology, 9. Retrieved June 21, 2014, from http://onlinelibrary.wiley.com/doi/10.1111/j.1472-4669.2010.00265.x/abstract

Reptiles. (n.d.). Monte San Giorgio. Retrieved June 21, 2014, from http://www.montesangiorgio.org/en/Monte-San-Giorgio/I-fossili/I-rettili.html

Switek, B. (2008, April 1). Heterodonty where you least expect it. Laelaps. Retrieved June 21, 2014, from http://scienceblogs.com/laelaps/2008/04/01/heterodont-archosaurs/