Megachirella -the mother of all lizards

A new international research rewrites the history of reptiles starting from a fossil found in the Dolomites.

The origin of lizards and snakes should be pushed back by about 75 million years, as documented by a small reptile, Megachirella wachtleri, found almost 20 years ago in the Dolomites and rediscovered today thanks to cutting-edge techniques in the field of 3D analysis and the reconstruction of evolutionary relationships. Evidence to this effect has been provided by an international paleontological research with the participation of the MUSE Science Museum of Trento, in collaboration with the “Abdus Salam” International Centre of Theoretical Physics of Trieste, the Enrico Fermi Centre of Rome and Elettra Sincrotrone Trieste. The results have been published in the prestigious science journal Nature, which has also dedicated its cover image to research.

The international team has identified Megachirella wachtleri – a small reptile which lived approximately 240 million years ago in what are today the Dolomites – the most ancient lizard in the world thereby providing key insight into the evolution of modern lizards and snakes.
The data – obtained by 3D X-ray imaging techniques and the analysis of DNA sequences – suggest that the origin of “squamates”, i.e. the group comprising lizards and snakes,is older than previously thought and that it can be dated to approximately 250 million years ago, before the most extensive mass extinction in history.

>Read more on the Elettra Sincrotrone Trieste website
>Watch here a video about the scientific discovery

Image: Megachirellawandering amidst the lush vegetation that approximately 240 million years ago surrounded the dolomitic beaches.
Credit: Davide Bonadonna

 

What makes pollen walls the most durable biological material?

Sporopollenin is the most durable biological material in nature and is a major component of the outer wall of pollen.

Scientists at the Natural History Museum (UK) and the ESRF are investigating the structure of the pollen wall this past weekend, on ID16A, to find out why this material is so resistant.

This experiment would not have taken place if chance, luck, but mostly curiosity had not played a major role in this story. ESRF post-doctoral researcher Ruxandra Cojocaru was talking to colleagues at the facility, looking for an appropriate material for a sedimentation study. Many discussions later, she ended up finding what she needed at the Natural History Museum in London, where curator and pollen specialist Stephen Stukins works.

Several exchanges later, and with an approved proposal for a different project than the original, they are now on ID16A to study the structure of pollen at nanolevel. “Throughout time, there have been species that have disappeared, yet the major plant groups have been relatively resistant to extinction. This may be due to the resistant sporopollenin material that was adapted for plant survival on land, especially exposure to UV radiation”, explains Stukins. With fellow NHM microfossil curator Giles Miller, he has brought fossil samples of Bathonian age, from the Jurassic era, that are part of the museum collection. “What we want to see is the structure of pollen, and more precisely of the sporopollenin outer wall. This is an almost inert biological polymer and we think it is key to the properties of pollen”, says Stukins.

>Read more on the European Synchrotron website

Image: the sample in its set-up at the European Synchrotron.
Credit: Montserrat Capellas Espuny

Research on the teeth of a prehistoric fetus

It gives us information about the last months of a mother and child, who lived 27.000 years BP.

Fossil records enable a detailed reconstruction of our planet’s history and of the evolution of our species. Dental enamel is a sort of biological archive that constantly tracks periods of good and bad health, while forming. Prenatal enamel, which grows during intrauterine life, reports the mother’s history as well.

We have studied fossil records found in the “Ostuni 1” burial site, discovered in Santa Maria di Agnano in Puglia in 1991 by Donato Coppola (Università di Bari, Italy) and dated back over 27,000 years. More specifically, we were interested in the teeth of a fetus found in the pelvic area of the skeleton of a young girl. By analysing the still forming teeth of the baby, it has been possible to obtain information about the health condition of the mother during the last months of pregnancy, to establish the gestational age of the fetus, and also to identify some specificities of the embryonal development. For the first time, it has been possible to reconstruct life and death of an ancient fetus and, at the same time, to shed light on its mother’s health.

Three still-forming incisors, belonging to the fetus, have been visualized and analyzed by means of X-ray microtomography at Elettra. The preliminary analysis on a portion of the fetal mandible, realized at the TomoLab laboratory allowed us to study the still-forming incisor contained within it (see Fig. 1). Thanks to the unique properties of synchrotron radiation and using a specifically-developed methodology, a high resolution 3D analysis has been carried out on the teeth at the SYRMEP beamline. This approach, allowed us to carry out a virtual histological analysis of the precious fossil teeth, revealing the finest structures of the dental enamel in a non-destructive way.

>Read more on the Elettra website

Image:  Pseudo color rendering of the virtual histological section of the Ostuni1b’s upper left deciduous central incisor. The corresponding CT scan has been acquired at the SYRMEP beamline in phase-contras mode.