Spiky Dinosaur May Have Been a Softy

Soft-tissue remains on an armored dinosaur may indicate a role other than warfare. Incidentally, how old are those red crusts, really?

Nature News shows the skull of an armored dinosaur that still has remains of keratin on its head spikes. “The thick body armour on some dinosaurs seems perfectly engineered to foil hungry predators,” Traci Watson writes, agreeing with most people’s intuitions. “But the remains of a newly discovered armoured dinosaur hint that its spiky suit had another role: showing off to potential mates and rivals.” Are those mean-looking spikes just a fashion statement? And what about that soft tissue?

The bony plates of armored dinosaurs often preserve well, but in life they were covered with a protein called keratin (the same insoluble protein found in fingernails, skin and hair). Theses proteins could have created attractive patterns of color, scientists at the Royal Tyrrell Museum of Palaeontology in Canada surmise. What they found on this beast, named Borealopelta markmitchelli, “exhibit the same growth pattern as antelope horns and other structures used for both defence and display,” according to museum experts.

The details add up to suggest that the evolution of B. markmitchelli’s flashy spikes was driven by the demands of social communication. The adornments might have provided a warning to potential foes, a lure to potential sexual partners —or both.

The argument that dinosaur armour had a role beyond protection makes sense, says vertebrate palaeontologist Thomas Holtz of the University of Maryland in College Park. “This is a nice indication that there is more to armour than absorbing damage,” he says.

Credit: Royal Tyrrell Museum of Palaeontology

Writer Traci Watson nowhere explores the obvious question: how could keratin protein survive for over a hundred million Darwin Years? All she does is describe it:

Fossils generally don’t reveal much about the size of a dinosaur’s spines when it was alive. Armoured dinosaurs were sheathed in bone plates, but that bone was also crowned by more flexible tissue made partly of keratin. Such soft tissue is seldom preserved in the fossil record, leaving researchers uncertain of the size and variety of these keratin caps.

But researchers got a rare glimpse of this soft tissue with the 2011 discovery in Canada of the first specimen of B. markmitchelli, which lived 110 million years ago. The exquisitely preserved fossil allowed Brown to measure both the keratin caps and bone plates from the animal’s snout to its hips. He found that the flatter bone plates closer to its tail were covered with a thin crust of keratin. But the keratin on the tusk-like spines protruding from the animal’s shoulders was much thicker, making up one-third of the spines’ length. Chunky keratin ornaments also capped the bone spikes on the animal’s neck.

Inverse Science reported in August that the keratin indicates that the dinosaur had a reddish hue.

Your precocious students can help confirm Darwinism! Here are science projects for their next school Science Fair:

1. Cut off a fingernail. Hide it in soil in a pot. Wait 110 million years, then check on its condition.
2. Wear a spike hairdo. See if it works better at attracting mates or defending against predator attacks.
3. Put the ‘demands of social communication’ on your pet cat. See if they drive the evolution of adornments.
4. Paint armadillos red, green, and yellow. See which colors the females like best.

After all, good science should be testable, shouldn’t it?