The world's tiniest dinosaur was less than two feet long

A tiny neck bone fossil measuring just a quarter-inch long was recently discovered in southern England. Dating back between 145 and 100 million years ago, the dinosaur that this bone belonged to can't have been more than 20 inches long.

That would make this newly discovered dinosaur, which doesn't yet have an official name, the smallest ever discovered. The current record holder is Anchiornis, which was a couple inches longer than this new creature and lived in China between 160 and 155 million years ago.

The discovery itself was a bit unusual. It was initially found back in 2009 by David Brockhurst, an amateur fossil hunter who found the bone in an old brickworks near his home in East Sussex. And then, as he explains, he just sort of sat on it for a while before turning it over to University of Portsmouth paleontologists Dr. Darren Naish and Dr. Steve Sweetman:

"I knew there was something about it that was different but I had no idea what it would turn out to be. It lay in my drawer for a while because I didn't know what to do with it. I couldn't believe it when they told me it was a completely new species. And then to find out it was possibly the world's smallest dinosaur. Amazing."

To put the magnitude (or lack thereof) of this new find in some perspective, North America's smallest known dinosaurs is Hesperonychus elizabethae. That dinosaur was only a foot and a half tall, and it weighed just four pounds. And yet this dinosaur was still a good six inches longer than this new discovery.

Admittedly, it can be tricky to extrapolate the exact measurements of a dinosaur from just a single fossil. This neck belonged to an adult dinosaur, which we know because its neurocentral suture has closed. This feature closes up once the dinosaur reaches maturity. The University of Portsmouth researchers are pretty sure that this dinosaur was feathered, but we can't tell much of anything about what it might have eaten or its other features.

However, the researchers can say with some certainty that this dinosaur was a maniraptoran, which is the group of dinosaurs that is thought to have ultimately evolved into modern birds. You can see an example of a maniraptoran dinosaur in the artist's conception up above - it's the one on the left that's about to be eaten by a bigger dinosaur, which must have been a pretty common fate for this particular species.

In order to figure out its length, the researchers used a couple of methods, although both are highly speculative when there's so little to go on. The first was, as researcher Dean Naish explains, almost wholly intuitive:

The intuitive method involved duplicating modified digital versions of the vertebra to make an 'articulated' neck (the digital vertebrae were modified since vertebrae within a neck are not all the same length). Said neck was then positioned within the silhouette of a generic, oviraptorosaur-like maniraptoran. This is definitely more art than science and I'm sure that it will make some people vomit with rage. It relies on the massive assumption that the silhouette is correct to begin with. I expect to be pelted with fruit, hit in the stomach etc. when next I go on the street. Anyway, whatever, the resulting scaled silhouette was about 45 cm long.

For those who aren't up on their metric conversions, that's about eighteen inches. In an effort to avoid beatings from roving gangs of paleontologists, Naish explains that they also used another, slightly more rigorous method relied on comparing the neck-to-body ratios of related dinosaurs to estimate the dinosaur's total length. That gave a range of about 33 to 50 centimeters, or 13 to 20 inches long.

Cretaceous Research via Tetrapod Zoology. Image via LiveScience.