Despite needing to prepare for my first class lecture for my upcoming Age of Dinosaurs class which meets in less than a week, setting up for my kids (twins) 4th birthday party, and being behind on at least 12 manuscripts, reviews, etc.... I for some bizarre reason have decided to try my hand at blogging. Over the last year and a half I have for various reasons regularly monitored several blogs including SV-POW, Tetrapod Zoology, Dracovenator, and Dinochick Blogs and feel compelled to tackle such a chore myself in order to expend some, hopefully, creative energy. Obviously, given my background and employer my posts may deal heavily in Late Triassic paleontology; however, I hope to include posts on other subjects as I feel inclined. I realize that once I get started I will need to post somewhat regularly and hope to provide at least one post a week. I am also toying with the idea of having "guest" bloggers occasionally fill in when my creative energy is nil. Thus I hope that readers will check back from time to time and hopefully enjoy some of my offerings. The first is below.
This story has been bouncing around for about three weeks right now, the discovery of some significant fossil vertebrates from the Late Triassic in Poland. Dr. Jerzy Dzik and colleagues have announced the find of a large theropod and dicynodont from a quarry in Lisowice in southern Poland. What is very interesting about these finds are 1) the proposed age of the deposit, and 2) the proposed taxonomic affinities of the theropod. The deposit is believed to date around 205 +/-5 ma which would make it very late Norian or Rhaetian in age. This is significant given the discovery of the dicynodont, which are not only very rare in Laurasia, but believed (with the exception of a purported Cretaceous occurrence in Australia) to have fallen victim to an extinction event before the end of the Triassic. This find extends the range of Triassic dicynodonts more than 10 million years. As a Triassic worker I find this interesting because recent work by myself and colleagues Randall Irmis, Sterling Nesbitt, and Jeff Martz have found that the Late Triassic faunas of the Chinle Formation and Dockum Group of the southwestern United States remain relatively conservative throughout the Norian and presumably the Rhaetian. Thus, the fauna from the Placerias Quarry, low down in the Chinle, is pretty similar to the fauna from Ghost Ranch which is much higher in the section. An exception to this appeared to be the dicynodonts, which had never been found in the upper Chinle or Dockum. Because of the Lisowice find, it appears that dicynodonts were present throughout the Late Triassic as well.
The theropod is of interest because of its large size (5m in length and 1.5 meters tall according to Dzik and colleagues) and because the preserved material, including an almost complete skull, suggest tetanuran affinities which would make it the earliest known member of that clade. This distinction was previously held by Zupaysaurus from the Late Triassic of Argentina, which in more recent studies is now believed to be a coelophysoid. A recent study by Nesbitt et al. (2007) has suggested that at least in North America theropod dinosaurs were not only rare components of Late Triassic faunas but only consisted of coelophysoids. Although this has not yet been confirmed by a rigorous study for the rest of Pangaea it appears that this may be true for the rest of the world as well, thus the new Polish find would be of some significance.
To date only a couple of preliminary articles, with some great photos of the material (here and here), have been put forth on what is being called the "Dragon of Lisowice" and hopefully the peer reviewed publications will be out soon.
Nesbitt, Sterling J., Randall B. Irmis, and William G. Parker. 2007. A critical reevaluation of the Late Triassic dinosaur taxa of North America. Journal of Systematic Palaeontology 5(2):209-243.
The Patagonian Land Penguin
8 hours ago in Catalogue of Organisms