This image was published in a paper entitled “Cenozoic megatooth sharks occupied extremely high trophic positions”, by Dr Emma Kast et al, in Science Advances (Vol 8 Issue 25). This graph illustrates the use of isotopic nitrogen ratios to reconstruct the trophic level of ancient megatooth sharks. The ratio of nitrogen isotopes present in fossil shark teeth indicates likely diet - the more nitrogen present, the higher the trophic level occupied by the shark. Swimming in the graph are the megalodon, Otodus megalodon, and the other shark species in its evolutionary line. Research shows the megatooth sharks occupied the highest trophic level of any known marine species, and were likely predators of predators. Perhaps not surprising for a shark that can reach 60 feet in length with teeth the size of a human hand!