Dragons, dinosaurs and Diamond

One of the coolest animals on the planet, just got cooler.  

If Komodo dragons weren’t fascinating enough already, it is now understood that the largest living predatory lizards have iron-clad teeth.  

This new finding, discovered as part of studies on Diamond’s I18 and B16 beamlines, explains why their serrated, blade-shaped teeth can stay sharp and lethal through their lifetime. Looking into the teeth characteristics of these “living fossils” may provide new ways to learn about the eating habits of carnivorous dinosaurs, which haven’t been previously available. 

A research team from King’s College London, led by Dr Aaron LeBlanc, aimed to discover what made the teeth of carnivorous dinosaurs so effective at cutting. They used Komodo dragons, the largest living lizards with small, blade-shaped teeth, as a modern comparison. The serrated teeth of Komodo make them a useful animal to study when trying to understand how the teeth of carnivorous dinosaurs. Dr LeBlanc’s team also looked at other serrated edged teeth from beavers, crocodiles and other reptiles.  

a, Lateral view of the skull of V. komodoensis (Natural History Museum, London, NHMUK 1934.9.2.1). b, Lingual view of a dentary tooth position showing several unerupted replacement teeth with orange pigmentation (American Museum of Natural History, AMNH 37912).

Advanced imaging revealed the teeth have a unique adaptation: orange, iron-enriched coatings on the serrations and tips, which help maintain their cutting edges.  

Iron teeth aren’t unique to reptiles – there are other animals with iron-infused enamel – but in Komodo dragons, the iron is concentrated along the cutting edges and tips of their teeth, staining them orange. This protective layer keeps the serrated edges of their teeth sharp and undamaged. On their teeth, iron is concentrated into a distinct coating of ferrihydrite, a type of iron oxide which bonds to crystalline structure of the enamel.  

This discovery is surprising because Komodo dragons have very thin enamel layers (only 15-20 micrometres thick) and they replace their teeth quite frequently. Typically, such thin enamel and rapid tooth replacement wouldn’t be expected to have such a distinct and durable iron coating.  

Dr LeBlanc, lecturer in Dental Biosciences at King's College London, said:

Polished thick section through mesial denticles of a tooth (Queensland Museum, Australia, J94036-2) showing orange pigmentation restricted to the enamel.

Fe K-edge X-ray Absoprtion Near Edge Structure (XANES) measurements were performed on the I18 beamline. X-ray Fluorescence (XRF) mapping was first undertaken to identify Fe-rich regions of interest within the enamel of the Komodo dragon tooth, as well as one from a saltwater crocodile (Crocodylus porosus) and the Canadian beaver (Castor canadensis) for comparison. 

Further X-ray micro fluorescence (XRF) and X-ray microdiffraction( XRD) analyses were conducted on B16 on fossil tyrannosaurid teeth. These techniques were used to examine the structure of the enamel as well as its elemental composition.  

Principal beamline scientist on I18, Konstantin Ignatyev, concluded: "This paper shows a great application of XANES and XRF techniques. When the research teams’ initial studies of dinosaur teeth didn’t yield the results they wanted, insights from Diamond have not only showed surprising information on existing animals. They also delivered a potential new path to investigating the question of dinosaur diets. Microfocus spectroscopy - which I18 specialises in - is highly important for the chemical and elemental analysis of heterogeneous materials on micron scale in all fields of science.

This paper shows a great application of XANES and XRF techniques. When the research teams’ initial studies of dinosaur teeth didn’t yield the results they wanted, insights from Diamond have not only showed surprising information on existing animals. They also delivered a potential new path to investigating the question of dinosaur diets. Microfocus spectroscopy - which I18 specialises in - is highly important for the chemical and elemental analysis of heterogeneous materials on micron scale in all fields of science.

LeBlanc, A.R.H., Morrell, A.P., Sirovica, S. et al. Iron-coated Komodo dragon teeth and the complex dental enamel of carnivorous reptiles. Nat Ecol Evol (2024). www.nature.com/articles/s41559-024-02477-7#article-info