Alessandro Urciuoli1, Clément Zanolli2, Josep Fortuny1,3, Sergio Almécija1,4, Burkhard Schillinger5, Salvador Moyà-Solà1,6,7, David M Alba1. 1. Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/Columnes s/n, Campus de la UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain. 2. Laboratoire AMIS, UMR 5288 CNRS, Université Toulouse III Paul Sabatier, Toulouse, France. 3. Centre de Recherches en Paléobiodiversité et Paléoenvironnements, Muséum National d'Histoire Naturelle, Bâtiment de Paléontologie, CP38, 8 rue Buffon, Paris 75005, France. 4. Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052. 5. Technische Universität München, Fakultat für Physik E21, James-Franck-Str.1, Garching D-85747, Germany. 6. Institució Catalana de Recerca i Estudis Avançats, Pg. Lluís Companys 23, Barcelona 08010, Spain. 7. Unitat d'Antropologia, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona 08193, Spain.
Abstract
OBJECTIVES: High-resolution imaging of fossils with X-ray computed microtomography (μCT) has become a very powerful tool in paleontological research. However, fossilized bone, embedding matrix, and dental tissues do not always provide a distinct structural signal with X-rays. We demonstrate the benefits of high-resolution neutron radiation in three different specimens showing problematic contrasts with X-ray μCT. MATERIALS AND METHODS: We compare neutron with X-ray μCT scans of fossils from two Miocene catarrhines from the Vallès-Penedès Basin: the cranium (IPS58443.1, holotype) of the putative stem hominoid Pliobates cataloniae, to discriminate between bone and matrix; and two lower molars (IPS1724n,o, holotype) of Barberapithecus huerzeleri, to discriminate among dental tissues. RESULTS: X-ray μCT scans of these specimens fail to retrieve any contrast between matrix/bone and enamel/dentine, whereas neutron μCT scans deliver high-contrast images, enabling a proper evaluation of the specimens' internal anatomy. DISCUSSION: Low bone/matrix intensity difference with X-ray μCT scans in IPS58443.1 is due to the extreme similarity in chemical composition between the matrix and the fossilized tissues, and the presence of high-density elements. In IPS1724, it is attributable to the convergence of enamel and dentine compositions during fossilization. On the contrary, neutron radiation returns very different contrasts for different isotopes of the same element and easily penetrates most metals. Neutron-based μCT scans therefore enable a correct definition of the bone/sediment and enamel/dentine interfaces, and hence a better segmentation of the images stack. We conclude that neutron radiation represents a successful alternative for high-resolution µCT of small-sized fossils that are problematic with X-rays.
OBJECTIVES: High-resolution imaging of fossils with X-ray computed microtomography (μCT) has become a very powerful tool in paleontological research. However, fossilized bone, embedding matrix, and dental tissues do not always provide a distinct structural signal with X-rays. We demonstrate the benefits of high-resolution neutron radiation in three different specimens showing problematic contrasts with X-ray μCT. MATERIALS AND METHODS: We compare neutron with X-ray μCT scans of fossils from two Miocene catarrhines from the Vallès-Penedès Basin: the cranium (IPS58443.1, holotype) of the putative stem hominoid Pliobates cataloniae, to discriminate between bone and matrix; and two lower molars (IPS1724n,o, holotype) of Barberapithecus huerzeleri, to discriminate among dental tissues. RESULTS: X-ray μCT scans of these specimens fail to retrieve any contrast between matrix/bone and enamel/dentine, whereas neutron μCT scans deliver high-contrast images, enabling a proper evaluation of the specimens' internal anatomy. DISCUSSION: Low bone/matrix intensity difference with X-ray μCT scans in IPS58443.1 is due to the extreme similarity in chemical composition between the matrix and the fossilized tissues, and the presence of high-density elements. In IPS1724, it is attributable to the convergence of enamel and dentine compositions during fossilization. On the contrary, neutron radiation returns very different contrasts for different isotopes of the same element and easily penetrates most metals. Neutron-based μCT scans therefore enable a correct definition of the bone/sediment and enamel/dentine interfaces, and hence a better segmentation of the images stack. We conclude that neutron radiation represents a successful alternative for high-resolution µCT of small-sized fossils that are problematic with X-rays.
Authors: Elin Törnquist; Sophie Le Cann; Alessandro Tengattini; Lukas Helfen; Joeri Kok; Stephen A Hall; Hanna Isaksson Journal: Front Bioeng Biotechnol Date: 2022-06-17
Authors: Marc E H Jones; Peter W Lucas; Abigail S Tucker; Amy P Watson; Joseph J W Sertich; John R Foster; Ruth Williams; Ulf Garbe; Joseph J Bevitt; Floriana Salvemini Journal: J R Soc Interface Date: 2018-06 Impact factor: 4.118