Evidence of pugnacious prehistoric fish unearthed
A nasty bruiser of a prehistoric fish, with sharp teeth jutting from his prominent jaw giving him a pugnacious glower, xiphactinus patrolled the shallow seas of what now is western Colorado some 85 million years ago.
Under circumstances unknown, though, the body of an individual xiphactinus settled, dead, to the floor of the Western Interior Seaway, possibly as a result of a shark attack, sometime in the late Cretaceous Period.
The bits and pieces of xiphactinus lay in the mud of what is now known as the mancos shale until part of the fish turned up about 10 years ago, when one of Susan Webster’s nephews was playing behind her house north of Grand Junction, she said.
Over the years, more bits and pieces were unearthed, enough that Webster contacted John Foster, curator of paleontology at Dinosaur Journey in Fruita, who set up a fish-digging expedition Friday.
Webster and her sons, Will Powell, 5, and Ford Powell, 9, joined Foster, Collections Manager ReBecca Hunt-Foster and several volunteers, who shoveled thin slices of shale and sifted it in search of pieces of bone, tendon, fin and tooth.
Three slightly curved pieces that looked like rib bone were, in fact, part of one of the creature’s pectoral fins, Foster said.
“Bone,” Ford shouted when handed a likely piece of rock from the sifter to run to Hunt-Foster, who was reassembling what she could of the fish on a card table.
Bit by bit, long broken bones fitted together. A chunk of jaw revealed a large empty tooth socket.
“That tooth would have been about the size of my pinkie,” Hunt-Foster said, fitting her finger into the socket.
Many xiphactinus found in places such as Iowa and Kansas are about 10 feet long, though one as long as 20 feet has been found.
The mancos shale yields some fossils, but most of them are oysters, ammonites and other, more simple forms of life.
“It’s nice to find a vertebrate in the mancos,” Foster said, examining one of several chunks of backbone found in the dig.
The search even yielded a clue as to the creature’s passing — a shark tooth evidently shed during feeding.
“I think the fish carcass must have been fed on, the sharks came in started picking on it,” Foster said.
The dig eventually surrendered more than just bits of bone when Foster found what appears to be a lower jaw with several teeth still embedded in the bone.
Xiphactinus will be displayed at some point at Dinosaur Journey, Hunt-Foster said, noting there is much to do with the jigsaw-like task of reassembling the remains of the fish before that.