Dinosaurs in bullet-proof vests

November 16, 2004

Their armour was perfect; even their eyelids consisted of plates of bone. What are known as ankylosauruses are among the best armoured animals known to us. These herbivores were up to ten metres long, with a tail ending in a huge bony club - 'probably used as a weapon', says Torsten Scheyer, 'even though they definitely could not simply swing it back and forth; the whole construction was simply too stiff for that.'

Torsten Scheyer has examined the dinosaurs' armour as part of his diploma thesis. The results are astonishing: 'The armour plating is not nearly as similar to those of the crocodile as was previously assumed,' he adds. 'Their microstructure is substantially more complex, at least in some types of ankylosaurus.'

A complete set of dinosaur chain mail was composed of hundreds of thousands of bony armour plates known as osteoderms. Most of these were smaller than a European one-cent coin, but some also had a diameter of several dozen centimetres and ended in long points. 'Unlike tortoise shells, the individual plates lay next to each other. They were not fused together,' the PhD student Torsten Scheyer explains. This kind of armour was flexible and could thus not break so easily under pressure. Although modern crocodiles have a similar kind of armour, the individual plates have a much simpler structure.

By using a polarisation microscope Torsten Scheyer discovered that collagen fibres were interwoven in the bone calcium of the dinosaur's armour plating, forming mats which were interspersed with each other three-dimensionally. Within each mat the fibres were aligned parallel to one another, with the fibres at right angles to the layer above and below them. 'The armour was thereby endowed with great strength in all directions,' Torsten Scheyer stresses. Today's composite materials are based on the same principle, which are used to make the rotor blades for wind farms or bullet-proof vests - except that in these cases the collagen mats are replaced by glass or carbon fibres.

Collagen is a protein found in connective tissue, sinews or cartilage. The ankylosauruses' armour plating was formed in the layer of connective tissue, thereby surrounding the existing collagen network. In the process of fossilisation this network decays, being replaced by minerals. 'In the fossils the pattern of the fibres can often still be traced, even after hundreds of millions of years,' Torsten Scheyer adds.

Some armour plating is even more stable

Palaeontologists divide the ankylosaurus into three subdivisions. The bullet-proof vest structure can only be proved in one of these; a second type has a relatively simple kind of armour plating. In the third group the armour paradoxically consists of what is known as haversian bone, a form which was first described in human beings in the 17th century by the British anatomist Dr. Clopton Havers. In the course of people's lives their bones are restructured. The trabeculae in the inside of the bones dissolve and are replaced by numerous small tubes of bone known as osteons. This reduces the stability of the bones and is one cause of the well-known phenomenon of brittle bones among the elderly. Torsten Scheyer explains, 'Ankylosauruses have these osteons, too, but in contrast to humans these are also strengthened with fibres.'

Possibly these collagen fibres are the reason why this third type of armour plating is even more stable than the 'normal' ankylosaurus armour. 'In this third group the plates of bone are far thinner than in all the other ankylosauruses - this cuts down weight and nutrients.' He adds, however, that despite this the armour was probably difficult to crack, not only because of their reinforcement with fibres: 'These thin plates of bone were shaped in such a sophisticated way that they could cope with pressure much better and did not break so easily.'
-end-


University of Bonn

Related Dinosaurs Articles from Brightsurf:

Ireland's only dinosaurs discovered in antrim
The only dinosaur bones ever found on the island of Ireland have been formally confirmed for the first time by a team of experts from the University of Portsmouth and Queen's University Belfast, led by Dr Mike Simms, a curator and palaeontologist at National Museums NI.

Baby dinosaurs were 'little adults'
Paleontologists at the University of Bonn (Germany) have described for the first time an almost complete skeleton of a juvenile Plateosaurus and discovered that it looked very similar to its parents even at a young age.

Bat-winged dinosaurs that could glide
Despite having bat-like wings, two small dinosaurs, Yi and Ambopteryx, struggled to fly, only managing to glide clumsily between the trees where they lived, according to a new study led by an international team of researchers, including McGill University Professor Hans Larsson.

Some dinosaurs could fly before they were birds
New research using the most comprehensive study of feathered dinosaurs and early birds has revised the evolutionary relationships of dinosaurs at the origin of birds.

Tracking Australia's gigantic carnivorous dinosaurs
North America had the T. rex, South America had the Giganotosaurus and Africa the Spinosaurus - now evidence shows Australia had gigantic predatory dinosaurs.

Ancient crocodiles walked on two legs like dinosaurs
An international research team has been stunned to discover that some species of ancient crocodiles walked on their two hind legs like dinosaurs and measured over three metres in length.

Finding a genus home for Alaska's dinosaurs
A re-analysis of dinosaur skulls from northern Alaska suggests they belong to a genus Edmontosaurus, and not to the genus recently proposed by scientists in 2015.

Can we really tell male and female dinosaurs apart?
Scientists worldwide have long debated our ability to identify male and female dinosaurs.

In death of dinosaurs, it was all about the asteroid -- not volcanoes
Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers.

Discriminating diets of meat-eating dinosaurs
A big problem with dinosaurs is that there seem to be too many meat-eaters.

Read More: Dinosaurs News and Dinosaurs Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.