New paleobiological perspectives on Iguanodon from the digitalization of the historical collection in Belgium

In 1878, more than thirty, almost complete, skeletons of Iguanodon were found in a mine in Bernissart (Belgium). Together with the English taxa studied by Owen and Leidy’s Hadrosaurus from the US – all based on more or less complete specimens – the Bernissart iguanodons shed a unique opportunity to realize what dinosaur really looked like in the early years of paleontology. Since then, these specimens are exhibited in the Royal Belgian Institute of Natural Sciences in Brussels. The Bernissart iguanodontians are thought to represent at least four different populations, and this offers a unique possibility to analyze intraspecific variations, behavioral interactions, paleopathology, and biomechanics. However, these materials suffer from severe pyrite decay, strongly limiting their accessibility for science and outreach. Here, we present the latest developments of the Belspo BRAIN-be 2.0 digitization project that aims to create a digital archive of the Bernissart individuals, currently encompassing two species, Iguanodon bernissartensis and Mantellisaurus atherfieldensis. Given the shiny and reflecting surface of the bones (provoked by the restoration resins and pyritization), we focused our methodology on structured-light surface scanners. The holotype of I. bernissartensis, the paratype of M. atherfieldensis, and at least ten other skeletons are now fully digitized in 3D and assembled in their most updated anatomical stance. The project shows that most of the individuals of I. bernissartensis possess similar body sizes, with greater variation of size and shape in the limbs. Some of the pathologies have been evaluated via tomography, whereas the skull of M. atherfieldensis was analyzed via microCT, showing discrepancies with the original osteological description. Future developments of the project will cover further paleobiological aspects of the behavior of Early Cretaceous iguanodontians, such as the use of the spike-like pollex and the range of motions of tails and limbs.