Press releases – April 2023

Whether it is new and groundbreaking research results, university topics or events – in our press releases you can find everything you need to know about the happenings at Goethe University. To subscribe, just send an email to

Goethe University PR & Communication Department 

Theodor-W.-Adorno Platz 1
60323 Frankfurt


Apr 11 2023

Extension for the looted property project at Frankfurt University Library: 349 looted volumes identified to date

Virtual 360° Tour of Looted Property Exhibition to Mark International Provenance Research Day

The exhibition "StolperSeiten – NS-Raubgut in der Universitätsbibliothek Frankfurt am Main" (“Stumbling Pages – NS looted property in the Frankfurt University Library") will be made available online as a virtual 360° tour on Provenance Research Day, which falls on April 12, 2023 this year. The exhibit is based on a project funded by the German Lost Art Foundation (Deutsches Zentrum Kulturgutverluste) as part of which the library is researching books in its inventory that can be attributed to persecutees of the Nazi era. The extension is the direct result of comparatively frequent finds, with the project now running until November 2024. There have already been several restitutions to Jewish and other organizations. 

"StolperSeiten" (Stumbling Pages) was the title of a much-noticed 2022 exhibition at the library on Nazi looted property at the Frankfurt University Library (“NS-Raubgut in der Universitätsbibliothek Frankfurt am Main"). This exhibition is now open again, but in the form of a virtual 360° tour. It spans the historical framework that led to the looting of hundreds of thousands of cultural assets in Germany and Europe from 1933 onwards. With its focus on the city of Frankfurt, and the city's libraries in particular, the exhibit addresses the role libraries played in the organized looting and how they profited from it, pointing out many concrete cases of injustice. In addition, the use of partially interactive elements also makes the work of contemporary provenance researchers more accessible. 

The online exhibit was designed as part of a project run by “fuels – Future Learning Spaces". Funded by the Hessian Ministry of Higher Education, Research, Science and the Arts, the joint project of Goethe University, Darmstadt Technical University and Darmstadt University of Applied Sciences aims to bring innovative technologies such as 360°, augmented and virtual reality into the university landscape. For more information, visit: 

Project to identify looted National Socialist property
In November 2020, Frankfurt University Library's (UB JCS) Provenance Research team started a project to identify looted National Socialist property in a first sub-collection comprising around 80,000 volumes. The search focuses on so-called "cultural property seized as a result of persecution", i.e. books that were looted or extorted from persecuted persons or institutions during the Nazi era. Commenting on the motives for researching Nazi looted property in the library, UB JCS director Daniela Poth says: "We consider it a moral obligation to uncover the injustice committed during the Nazi era and to document it in public, even if this does not make up for it. That is something university management, library management and project management all agree on." The project at Goethe University's UB JCS is sponsored by the German Lost Art Foundation. In addition, given the fact that many of the affected books are on permanent loan at the UB JCS but historically belong to the municipality, the city of Frankfurt is also providing a subsidy for the project costs. 

Following the approval for an extension – itself based on the comparatively high number of finds – the project will now run until November 2024, and therefore already passed its halftime mark a few months ago. Time for an interim assessment. To date, almost 40,000 volumes have been individually checked on the shelf for any references to previous owners. This has turned out to be the case in an unusually high percentage of about 39%. As a result, more than 15,000 volumes have had to be examined more closely to clarify whether the suspicion of looted property is merited. Such an initial suspicion exists for over 3,800 books. Another 200 books have met with strong suspicion, whereas 349 books have been confirmed as cases of looted property. However, the project team's work does not end with the investigation into actual numbers or with the documentation of these cases on UB JCS' freely accessible search portal. For all confirmed cases of looted property, the project staff also researches the existence of descendants or successor institutions. If this search, which can be very complex, is successful, the library contacts the potential restitution recipients and clarifies whether they desire a return, or would prefer another "fair and just solution". 

The fact that it took some time after the start of the project before the first restitutions could be both prepared and carried out illustrates just how time-consuming research and coordination are. Within the last six months, three books were restituted to the Jewish Community of Munich and Upper Bavaria, one book to the Jewish Religious Community of Baden and eight volumes to the Minerva Lodge of the Three Palms in Leipzig. Corresponding references to these volumes are available in the library's search portal – as virtual "StolperSeiten". Further restitutions are in the preparatory stage and expected to be completed during the course of the year. 

Further information: Dr. Mathias Jehn, Head of the Department "Curating Subject Information Mediation", J. C. Senckenberg University Library, Bockenheimer Landstraße 134-138, 60325 Frankfurt, Tel: +49 (69) 798 39007, Mail: 

Contact for general press inquiries: Bernhard Wirth, Staff Development and Public Relations of the Library, Tel. +49 (69) 798 39223; Mail:

Editor: Dr. Dirk Frank, Press Officer, PR & Communication Office, Theodor-W.-Adorno-Platz 1, 60323 Frankfurt am Main, Tel: +49 (0) 69 798-13753,


Apr 4 2023

International research team from Germany, Austria, Canada, the Netherlands and the USA applies new carbonate analysis method to eggshells from Troodon, reptiles and birds

Analysis of dinosaur eggshells: bird-like Troodon laid 4 to 6 eggs in a communal nest

An international research team led by Goethe University Frankfurt, Germany, determined that Troodon, a dinosaur very close to modern birds, was a warm-blooded animal (an endotherm), but had a reproductive system similar to that of modern reptiles. The scientists applied a new method which allowed for accurate determination of the temperature when the egg's carbonate shell was formed. Furthermore, the researchers showed that Troodon laid 4 to 6 eggs per clutch. As nests with up to 24 Troodon eggs had been found, the scientists conclude that several Troodon females laid their eggs in communal nests.

FRANKFURT. In millions of years and with a long sequence of small changes, evolution has shaped a particular group of dinosaurs, the theropods, into the birds we watch fly around the planet today. In fact, birds are the only descendants of dinosaurs which survived the catastrophic extinction 66 million years ago that ended the Cretaceous period.

Troodon was such a theropod. The carnivorous dinosaur was about two meters long and populated the vast semi-arid landscapes of North America about 75 million years ago. Like some of its dinosaur relatives, Troodon presented some bird-like features like hollow and light bones. Troodon walked on two legs and had fully developed feathery wings, but its relatively large size precluded it from flying. Instead, it probably ran quite fast and caught its prey using its strong claws. Troodon females laid eggs more similar to the asymmetric eggs of modern birds than to round ones of reptiles, the oldest relatives of all dinosaurs. These eggs were coloured and have been found half buried into the ground, probably allowing Troodon to sit and brood them.

An international team of scientists led by Mattia Tagliavento and Jens Fiebig from Goethe University Frankfurt, Germany, has now examined the calcium carbonate of some well-preserved Troodon eggshells. The researchers used a method developed by Fiebig's group in 2019 called “dual clumped isotope thermometry". By using this method, they could measure the extent to which heavier varieties (isotopes) of oxygen and carbon clump together in carbonate minerals. The prevalence of isotopic clumping, which is temperature-dependent, made it possible for scientists to determine the temperature at which the carbonates crystallized.

When analyzing Troodon eggshells, the research team was able to determine that the eggshells were produced at temperatures of 42 and 30 degrees Celsius. Mattia Tagliavento, leading author of the study, explains: “The isotopic composition of Troodon eggshells provides evidence that these extinct animals had a body temperature of 42°C, and that they were able to reduce it to about 30°C, like modern birds."

The scientists then compared isotopic compositions of eggshells of reptiles (crocodile, alligator, and various species of turtle) and modern birds (chicken, sparrow, wren, emu, kiwi, cassowary and ostrich) to understand if Troodon was closer to either birds or reptiles. They revealed two different isotopic patterns: reptile eggshells have isotopic compositions matching the temperature of the surrounding environment. This is in line with these animals being cold-blooded and forming their eggs slowly. Birds, however, leave a recognizable so-called non-thermal signature in the isotopic composition, which indicates that eggshell formation happens very fast. Tagliavento: “We think this very high production rate is connected to the fact that birds, unlike reptiles, have a single ovary. Since they can produce just one egg at the time, birds have to do it more rapidly."

When comparing these results to Troodon eggshells, the researchers did not detect the isotopic composition which is typical for birds. Tagliavento is convinced: “This demonstrates that Troodon formed its eggs in a way more comparable to modern reptiles, and it implies that its reproductive system was still constituted of two ovaries."

The researchers finally combined their results with existing information concerning body and eggshell weight, deducing that Troodon produced only 4 to 6 eggs per reproductive phase. “This observation is particularly interesting because Troodon nests are usually large, containing up to 24 eggs", Tagliavento explains. “We think this is a strong suggestion that Troodon females laid their eggs in communal nests, a behaviour that we observe today among modern ostriches."

These are extremely exciting findings, Jens Fiebig comments: “Originally, we developed the dual clumped isotope method to accurately reconstruct Earth's surface temperatures of past geological eras. This study demonstrates that our method is not limited to temperature reconstruction, it also presents the opportunity to study how carbonate biomineralization evolved throughout Earth's history."

Publication: Mattia Tagliavento, Amelia J. Davies, Miguel Bernecker, Philip T. Staudigel, Robin R. Dawson, Martin Dietzel, Katja Goetschl, Weifu Guo, Anne S. Schulp, François Therrien, Darla K. Zelenitsky, Axel Gerdes, Wolfgang Müller, Jens Fiebig: Evidence for heterothermic endothermy and reptile-like eggshell mineralization in Troodon, a non-avian maniraptoran theropod. PNAS (2023)

Images for download:

Caption: Artist's impression of two Troodons with a common nest. Illustration: Alex Boersma/PNAS

Participating partners:
Institute of Geosciences, Goethe University Frankfurt, Germany.
Frankfurt Isotope and Element Research Center (FIERCE), Goethe University Frankfurt, Germany.
Institute of Applied Geosciences, Graz University of Technology, Austria.
Royal Tyrrell Museum of Palaeontology, Drumheller, Canada.
Department of Geoscience, University of Calgary, Canada.
Naturalis Biodiversity Center, Leiden, the Netherlands.
Deptartment of Earth Sciences, Universiteit Utrecht, the Netherlands
Department of Geosciences, University of Massachusetts, USA.
Morrill Science Center, Amherst, USA
Department of Geology and Geophysics, Woods Hole Oceanographic Institution, USA

Thermometers for Earth history: "Dual clumped isotope" method for carbonate analysis (2020).

Further information:

Goethe University Frankfurt
Institute for Geosciences

Dr. Mattia Tagliavento
Phone. +49 176 64735849

Professor Jens Fiebig
Phone: +49 (0) 69 798 40182

Naturalis Biodiversity Center
and Utrecht University, Leiden/Utrecht, The Netherlands

Professor Anne S. Schulp (English, German, Dutch)
Phone: +31 6 51229317 /

Twitter-Handles: @goetheuni @UUGeo @UMass @UniGraz @WHOI @Naturalis_Sci @RoyalTyrrell @UCalgarySWC @anneschulp  @Naturalis_Sci @museumnaturalis

Editor: Dr. Markus Bernards, Science Editor, PR & Communication Office, Tel: -49 (0) 69 798-12498, Fax: +49 (0) 69 798-763 12531,