SEATTLE – The fossil has the sexy name of UWBM 96770, but at the Burke Museum in Seattle, they’re pretty excited.

The fossil is not that big – 1 1/2-feet long, weighing maybe 15 pounds.

But it is the first dinosaur bone ever found in Washington.

It was a leg bone from an animal from the T. rex family, but smaller by tyrannosauroid standards – around 36 feet long.

Still, think of a transit bus to imagine its size. Think of a carnivorous transit bus with bone-crunching teeth.

The fossil is a rarity in the state because it goes back 80 million years.

Much of the land mass that encompasses the region didn’t exist in those days. It was mostly under water; obviously, not a place for land-roaming big guys.

That’s why Washington’s official state fossil is much younger.

The Columbian mammoth, with its big, curved tusks, was found in Western Washington until as recently as 10,000 years ago.

This fossil was found in April 2012. Three years later, we have the big unveiling.

“It’ll be a point of civic pride for this state. We’re now the 37th state to have found a dinosaur fossil,” said Brandon Peecock, a University of Washington graduate student and co-author of the paper about the find.

As can happen with such discoveries, it was by accident.

The fossil was found along the shore – at the high-water mark – at Sucia Island State Park in the San Juans.

University of Washington researchers were collecting fossils of extinct marine invertebrates called ammonites. But then the researchers came upon an unusual sight: “A slightly discolored, whitish lump, and they could see spongy bone texture. It was different from the surrounding rock where it was embedded,” said Christian Sidor, Burke Museum’s curator of vertebrate paleontology.

The fossil was chiseled out over a period of hours.