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Hi everyone! I have just returned from a fieldschool to Poland which was organized by the BVP (Belgium Society for Paleontology) in association with the Universities of Opole and Gdansk. The fieldschool started on the 9th july and ended on july 17. The first 2-3 days of the trip took place in the historic city of Gdansk which lies by the Baltic Sea where the main focus was on Baltic Amber. This included lectures, workshops, a small museum tour and some trips to the beach in search for amber. For the 2nd part of the trip we travelled to the south towards Opole and more specifically the Jurapark and digsite in Krasiejow where we had multiple lectures, workshops, and fieldwork in both Krasiejow and other quarries in the area. So in this topic I wanted to make a day by day report on this amazing trip and experience. Since we travelled by car I only returned yesterday evening so most of the finds still have to be photographed/prepped so expect them somewhere at the end of this topic (which might also take a few days to complete.)

Dear members, It’s time for another “review” of a palaeontological site I had the pleasure to excavate in. However this one is quite different from the others I already posted about: those were outcrops in Ohio, USA, where you could collect fossils freely or by signing a disclaimer. This time, instead, I had to operate alongside the institution that holds the concession to excavate and study the material. For fifteen days in August 2019 I excavated in the Late Triassic beds of Krasiejów, southwestern Poland, alongside the Institute of Paleobiology of the Polish Academy of Sciences, based in Warsaw. It is not the only “official” dig that I took part in, but, alas, the only I’m allowed to post pictures of! Krasiejów’s site has been exploited for the extraction of clay since the beginning of the XX century until 2002; the first scientific excavations took place in 1993 and the first publication was issued in 2000. Since then dozens of students and palaeontologists from all over the world have visited the site. The assemblage dates to the Late Triassic, but a more precise dating (Carnian or Ladinian) has not been assessed yet. Back then Poland was situated much southern on the Northern hemisphere, under subtropical conditions. Rivers formed extensive backwaters and swamps, separating islands from the dry mainland. Occasionally, intensive rainfall led to flooding that washed out skeletal remains and transported them to their final site of burial. Bones were then scattered and damaged, but rapid deposition led to their preservation. Krasiejów can therefore be classified as a Konzentrat-Lagerstätte. A section of the Bonebed is open to the public and it’s a truly mind-blowing sight! Dozens of skulls, mandibles and isolated bones of amphibians (later I’ll tell you exactly of which species) can be seen lying there since 220 million years ago. I pictured a small section of the bonebed, circling in yellow the skulls and in red the mandibles. The lithotypes that make up the outcrop are red claystone and grey pelites. Tools needed for excavating are geological hammers, pickaxes and shovels. That's what an usual day on the site looked like: The flora and invertebrate assemblage is not very rich: conifer cone scales and branches, freshwater bivalves and small arthropds. Fish were scarce and poorly preserved. In the case of lungfish, instead, toothplates were common: The most interesting aspect is represented by tetrapod bones: they are countless, even in my wildest dreams I could not have hoped of finding so many as I have! Metoposaurus was a temnospondyl amphibian characterized by a dorsoventrally flattened body up to 2 m (6,5 ft) long. Its bones are the most common remains in Krasiejów. It probably lived at the bottom of shallow-water reservoirs, as ambush predator hunting for fish and other small vertebrates. For air it had to resurface regularly, but it may not have been able to enter land. The bones on the bonebed belonged to it. Here you can see a close up of a mandible ramus from two perspectives, two ribs, a vertebra and interclavicle. Ciclotosaur, another temnospondyl amphibian, hunted on both water and land. It’s not easy to differentiate its bones from those of Metoposaurus on the field. Paleorhinus was a phytosaur, a 3,5 m (11,5 ft) long semi-acquatic predator superficially resembling a gavial. I have found a couple of teeth that belonged to it. Stagonolepis was a herbivorous, 3,5m long archosaur with a heavily armoured body. Its skull was small and equipped with conical teeth and a horny beak on the mandible and a fleshy snout on the upper jaw. It may have used them to dig food out of the ground. Osteoderms and teeth (not pictured) were rather common. We also found a femur of Stagonolepis: And a bone of the hind limb, that in order to be extracted and protected was covered with a field jacket of gypsum: Finally, a rauisuchian and dinosaur species make up the assemblage, but we didn’t find any of their bones since they are extremely rare. If you'd like to know more about Krasiejów, I suggest you to read these two papers: - Gruntmejer, K., Konietzko-Meier, D., & Bodzioch, A. (2015). The Triassic world of Krasiejów. FIELD GUIDE, 17. - Dzik, J. and Sulej, T. 2007. A review of the early Late Triassic Krasiejów biota from Silesia, Poland. Palaeontologia Polonica 64, 3–27. Well, that’s it! This excavation was an incredible experience for me, I met some great people and found amazing fossils! I hope you enjoyed and leave a comment if you have any question for me!! Fabio