Final Report Summary - BONE SCAN (Traces in the bones: reconstructing the lost soft anatomy of the earliest vertebrates through ultra-high resolution synchrotron scanning.)
The project has pioneered the application of a cutting-edge imaging technology, propagation phase contrast synchrotron microtomography, to fossils of early vertebrates (backboned animals). Using this technique we are able to produce three-dimensional computer images of the internal structure of the fossils, up to resolutions of about one thousandth of a millimetre, without cutting them or damaging them in any way. This creates revolutionary new possibilities for understanding the structure of the fossils, their biology as once-living organisms, and their evolution. The work has been carried out in collaboration with Beamline ID19 of the European Synchrotron Radiation Facility (ESRF) in Grenoble, which is the world leader in this technology; one member of our team, Sophie Sanchez, was stationed there for two years to learn all aspects of the technique under the supervision of Paul Tafforeau, Beamline Scientist in charge of ID19 and foremost expert on synchrotron tomography of fossils in the world.
We have focused most of our work on the histology, that is the cellular microstructure, of hard tissues such as bone and dentine. This internal microstructure is frequently almost perfectly preserved, even in fossils hundreds of millions of years old, and forms a very rich source of information. We have studied both fossils and corresponding structures from living animals which help us to understand the fossil material. In the past, histology has been studied two-dimensionally using thin sections cut from the fossils: we have discovered that three-dimensional models are far more informative and easier to understand. One of our most important discoveries is that muscle attachments on fossil bones can be identified from the attachment fibres that are still embedded in the bone. The orientation of the fibres shows the direction of the muscle. This promises to help enormously with the reconstruction of fossils as living, moving animals. We have also gained a radically improved understanding of how hard-tissue structures such as scales and bones grew in different groups of early vertebrates. Among many other discoveries can be mentioned the identification of spaces for an organized bone marrow - the earliest in the world - in the upper arm bone of the lobe-finned fish Eusthenopteron (which lived 380 million years ago and was a close relative of the first land vertebrates). At present our group is the world leader in three-dimensional, synchrotron-based histological research on fossils.
In addition to histology, we have also studied the morphology - the anatomical structure and body form - of early vertebrates using synchrotron tomography. Two discoveries in this area have made great impact and have both been published in the leading scientific journal Nature. One concerns the backbone of the tetrapod (early land animal) Ichthyostega, where we were able to show that its vertebrae were constructed quite differently from those of any other known tetrapod. The other concerns the evolutionary transition from jawless to jawed vertebrates, when the entire face was rebuilt and the brain changed shape. By modelling the face and the cranial cavity (the space where the brain lay) of the very early jawed vertebrate Romundina, we were able to show that it represented an intermediate step in this remarkable transition, which helps to explain how the transformation of the face and brain came about. The results of this study don't just tell us about evolution, but also cast new light on the way the face develops in the embryo.
Propagation phase contrast synchrotron microtomography has proved to be an immensely powerful tool for studying the internal structure of fossils. We plan to continue pursuing this technique in our research and develop new ways of applying it to problems of structure,function and evolution in early vertebrates.
We have focused most of our work on the histology, that is the cellular microstructure, of hard tissues such as bone and dentine. This internal microstructure is frequently almost perfectly preserved, even in fossils hundreds of millions of years old, and forms a very rich source of information. We have studied both fossils and corresponding structures from living animals which help us to understand the fossil material. In the past, histology has been studied two-dimensionally using thin sections cut from the fossils: we have discovered that three-dimensional models are far more informative and easier to understand. One of our most important discoveries is that muscle attachments on fossil bones can be identified from the attachment fibres that are still embedded in the bone. The orientation of the fibres shows the direction of the muscle. This promises to help enormously with the reconstruction of fossils as living, moving animals. We have also gained a radically improved understanding of how hard-tissue structures such as scales and bones grew in different groups of early vertebrates. Among many other discoveries can be mentioned the identification of spaces for an organized bone marrow - the earliest in the world - in the upper arm bone of the lobe-finned fish Eusthenopteron (which lived 380 million years ago and was a close relative of the first land vertebrates). At present our group is the world leader in three-dimensional, synchrotron-based histological research on fossils.
In addition to histology, we have also studied the morphology - the anatomical structure and body form - of early vertebrates using synchrotron tomography. Two discoveries in this area have made great impact and have both been published in the leading scientific journal Nature. One concerns the backbone of the tetrapod (early land animal) Ichthyostega, where we were able to show that its vertebrae were constructed quite differently from those of any other known tetrapod. The other concerns the evolutionary transition from jawless to jawed vertebrates, when the entire face was rebuilt and the brain changed shape. By modelling the face and the cranial cavity (the space where the brain lay) of the very early jawed vertebrate Romundina, we were able to show that it represented an intermediate step in this remarkable transition, which helps to explain how the transformation of the face and brain came about. The results of this study don't just tell us about evolution, but also cast new light on the way the face develops in the embryo.
Propagation phase contrast synchrotron microtomography has proved to be an immensely powerful tool for studying the internal structure of fossils. We plan to continue pursuing this technique in our research and develop new ways of applying it to problems of structure,function and evolution in early vertebrates.