A sharp concept revealed: Komodo dragons keep their teeth razor sharp thanks to an iron-containing coating, according to a study. The orange shimmering structure apparently enables the rabid reptiles to deliver a fatal, lasting bite. Although not as pronounced, the researchers were also able to detect iron deposits in the tooth enamel of other reptiles. However, only new detection methods can clarify the extent to which the teeth of predatory dinosaurs were also made of iron.
They are probably the closest to the creatures of myths: the inhabitants of some Indonesian islands, also known as Komodo dragons (Varanus komodoensis), are the largest representatives of the monitor lizards still alive today. They can reach lengths of three meters and weigh over 80 kilograms.
They are notorious predators: Komodo dragons can even overpower large prey such as deer, horses or even water buffalo. They do this by biting them and then tearing pieces out of the victims. They are equipped with slightly curved teeth, the edges of which have sharp serrated structures.
Due to their characteristics, the rabid reptiles have also become the focus of paleontology. Their diet and the shape of their teeth show interesting parallels to the characteristics of predatory dinosaurs such as Tyrannosaurus rex and others. This is why researchers led by Aaron LeBlanc from King’s College London have now devoted a detailed study to the teeth of the Komodo dragons. First, they examined numerous teeth of the reptiles from museum collections.
Iron turns the edges orange
The researchers identified a basic tooth feature that was initially thought to be discoloration caused by food particles: the cutting edges and tips of each tooth have an orange color. The researchers found that this feature also characterizes teeth that have not yet broken through the gums. They therefore subsequently examined this material using electron microscopy, mass spectrometry and X-ray fluorescence analysis.
It was shown that the coloring is due to high levels of iron in the tooth enamel. As the researchers explain, this component strengthens the tips and cutting edges of the teeth, which are otherwise only thinly coated with enamel. The iron-rich structure ensures that they are protected from the mechanical stresses of biting and tugging on animal tissue and remain razor-sharp. Similar iron deposits were already known in mammals: they protect the teeth of beavers from wear, for example. But they have not yet been discovered in reptiles. Further investigations by the researchers showed that at least some iron is present in the teeth of various representatives of this animal group. However, they have so far only found it in Komodo dragons in such a high concentration that it leads to a clearly visible color effect.
Even with predatory dinosaurs?
The team then investigated whether the teeth of some predatory dinosaur species might have been similarly made of iron. “Komodo dragons have curved, serrated teeth that they can use to tear apart their prey, just like carnivorous dinosaurs,” LeBlanc emphasizes. But in their examination of numerous fossil teeth of predatory dinosaurs, they found no evidence of iron coatings. However, they suspect that this is due to the iron components disappearing during fossilization processes. They could not even find any evidence of iron coatings in fossil teeth of relatives of Komodo dragons.
“Unfortunately, with the technology we currently have, we cannot determine whether fossilized dinosaur teeth had a high iron content or not. We believe that the chemical changes mask how much iron was originally present,” says LeBlanc. However, the investigations into the dinosaur teeth were not unsuccessful: The researchers were able to show that various concepts for stabilizing tooth structures have apparently been developed over the course of evolution.
discovered structural peculiarities in the jagged tooth enamel of some large predatory dinosaurs: the crystalline structure was arranged in a spiral pattern. As the team explains, this probably counteracted the spread of cracks.
As they conclude, it may become clear in the future whether iron deposits also contributed to the sharp bite of dinosaurs. “By further analyzing the Komodo dragon teeth, we may be able to find additional traces of iron coating that were not altered during fossilization. Such evidence could then clarify whether dinosaurs also had iron-coated teeth or not,” says LeBlanc.
Source: King’s College London, specialist article: Nature Ecology & Evolution, doi: 10.1038/s41559-024-02477-7