Around 165 million years ago on a coastal floodplain in what is now Morocco lived one of the most extreme dinosaurs on record, lavishly adorned with armor and spikes - some about three feet (one meter) long - unlike that of any other known creature.

Researchers on Wednesday described extensive fossilized remains discovered in the Atlas Mountains near the Moroccan town of Boulemane of a Jurassic Period dinosaur named Spicomellus. Roughly 13 feet (four meters) long and weighing perhaps one to two tons, Spicomellus is the oldest-known member of a group of tank-like armored dinosaurs called ankylosaurs, squat and slow-moving plant-eaters that walked on four legs.

"The armor of Spicomellus is jaw-droppingly weird, unlike that of any other dinosaur - or any other animal alive or dead - that we've ever discovered," said vertebrate paleontologist Richard Butler of the University of Birmingham in England, co-leader of the research published in the journal Nature.

"Not only did it have a series of sharp, long spikes on each of its ribs - unknown elsewhere among animals - but it had spines the length of golf clubs sticking out in a collar around its neck," Butler added.

The extravagant armor may have served dual roles - as defense against large meat-eating dinosaurs and as display to attract mates.

"The armor surely had some defensive function, but it's difficult to imagine how the meter-long spikes around the neck were used for defense. They seem like enormous overkill," Butler said.

In living animals, structures that tend to have no obvious function and look like they might be a bit annoying to carry about - like a deer's antlers or a peacock's tail - are usually associated with sex, according to vertebrate paleontologist and study lead author Susannah Maidment of the Natural History Museum in London.

"They could be used in courtship or territorial displays, or to fight against members of the same species during competitions for mates. Spicomellus' armor is totally impractical, and would have been a bit annoying in dense vegetation, for example. So we think that it is possible the animal evolved such elabora...