422-million-year-old fish jaw reveals how teeth evolved
Life on Earth is the result of millions of years of fine-tuning – an evolution which often hides details of how things gradually became the way they are in extinct species, for curious scientists to discover. Here they use high-resolution x-ray microtomography to picture the jawbone of a fossilised bony fish Lophosteus, revealing its 422-million-year-old teeth (highlighted in gold) and virtually 'removing'the bone to peek at the blood vessels and pulp cavities (blue and green) underneath. This fish was picked for a reason – it’s an early window into the evolution of teeth, showing that structures called dermal odontodes (purple pink and red) developed from similar cells to teeth, becoming nearby 'skin teeth' – the scales in fish like sharks. The co-development of these structures reveals more about the chemical signals driving how teeth develop and grow, and may provide insights into the signals shaping human gnashers too.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.