When Oak Bluffs firefighters responded to a fully involved fire on Barnes Road late Wednesday night, they knew that they had more than just a house to save. A quick response by volunteer firemen saved both the summer home owned by Dr. Henry J. Kriegstein and a rare seven-and-a-half foot tall prehistoric dinosaur skull that was inside.

The foyer at the Kreigstein home.

“We had prior knowledge of that fossil being in there so we were able to protect that pretty quickly,” said Oak Bluffs acting fire chief John Rose. Dr. Kriegstein, an eye surgeon with a fossil collecting hobby, said the triceratops skull in his Oak Bluffs home is one of few that exist in the world and is believed to be more than 43 million years old.

The fire call came in around 9 p.m. on Wednesday. Oak Bluffs volunteer firefighters responded within minutes. Mutual aid came from Edgartown, Tisbury and West Tisbury. Police from Oak Bluffs as well as state police arrived at the scene and directed traffic. Barnes Road was blocked off for almost two hours from Concord avenue to Oak Wood Lane.

“The exterior of the house was burned pretty severely but we saved the inside of the house; there really wasn’t much damage to the inside of the house,” Chief Rose said Thursday after spending much of the day at the scene.

The chief said the house was vacant at the time of the fire. The cause remains under investigation but is believed to be combustion from materials connected to a floor refinishing project. “The preliminary investigation is pointing toward the origin and cause of the fire being sawdust and materials used to refinish floors catching on fire,” Chief Rose said.

It took firefighters around an hour to get the blaze under control. Barnes Road reopened just before 11 p.m. and firefighters left the scene by 11:30 p.m.

The incident occurred in a week when the town water supply was operating differently due to the fact that the standpipe is being painted. A temporary connection to the Edgartown water supply is in place. Coincidentally, earlier Wednesday evening firefighters in Oak Bluffs and West Tisbury had held a drill to practice drafting from tanker trucks to provide water for structure fires.

“We had mutual aid from West Tisbury to make sure we had a sufficient water source to fight a fire,” Chief Rose recounted.

“And then we had a structure fire.”

He said no problems were encountered at the scene. “We had more than enough water to fight the fire,” the chief said. But he said it was challenging, with the temperature at 27 degrees, and smoky conditions. “There was a lot of firefighter rehab. EMS was there the whole time,” the chief said.

And firefighters had the added task of protecting the rare dinosaur skull.

“We were careful with water use inside the house and made sure the fossil didn’t tip over or anything like that,” Chief Rose said. “It’s a very rare fossil. Only a couple like it in the world. Very insane.”

The rare prehistoric relic came to the Island a decade ago after Dr. Kriegstein collected it from a ranch outside of Baker, Mont.

“Collecting fossils is definitely a hobby,” Dr. Kriegstein said when reached by telephone Thursday afternoon at his office in Plymouth. “Heads and tails and arms and legs of different animals.”

A 2004 story in the Gazette recounted how after taking a trip with his daughter to collect the fossilized skull, Dr. Kriegstein assembled a team of local builders, contractors and heavy machinery to transport the triceratops skull from a rural Montana ranch to his Island summer home. Once it arrived atop a Hinckley’s Lumber truck, it was moved inside the home, where Island builder Tom Burke customized a foyer for the skull.

Dr. Kriegstein said he learned of the fire from his wife Joan who received a call from the fire department. The Kriegsteins live in Hingham.

“My wife spoke to Chief Rose but I didn’t,” Dr. Kriegstein said. He said one of the first things his wife told him was that the fossil was saved.

“I am so glad somebody driving by saw it and called it in. It could have been a lot worse,” he said.“But it wasn’t. And we are both so grateful.”