WOODLAND PARK — Surrounded by a collection of fossilized sea creatures with huge, menacing teeth, the prehistoric fish head a little larger than a man’s hand doesn’t look like much.
But the fossil of a Rhinconichthys is one of only three now known in the world, Bruce Schumacher, a U.S. Forest Service paleontologist, said Thursday. “It doesn’t have a wow factor like T-Rex, but there are lots of those fossils. What it lacks, it has to the nth degree in terms of scientific significance.”
Schumacher unveiled the fossil, and a cast made from it, to the assembled media at the Rocky Mountain Dinosaur Resource Center, where the cast will be on display.
The center’s curator, Anthony Maltese, prepared the fossil, which was displayed in a hall that is home to fossils of predatory sea creatures with gaping jaws and large teeth.
The fossil itself will be part of the Denver Museum of Nature and Science’s collection.
Unlike mosasaurs, marine reptiles, and other sea creatures that lived at the same time as this fish during the Cretaceous period, this creature had no teeth.
It did have large eyes and an “underbite so severe it looked like it couldn’t close its jaws,” Maltese said.
With a lower jaw that was longer than its upper jaw, the animal wouldn’t have been able to close its mouth easily, and probably held it wide open most of the time.
The fish — with its gaping mouth and huge eyes — reminds Maltese of the Muppet Beaker, earning it the nickname “muppet fish.”
When feeding, it strained food particles from water using a specialized filtering structure, similar to that used by some sharks, baleen whales and other sea creatures.
Before the Rhinconichthys’ fossils were found, scientists didn’t know there were any prehistoric filter feeding fish.
Schumacher found the fossil in September 2012, while on a geologic survey in the Comanche National Grassland in southeastern Colorado, as he walked through a dry wash in the Purgatoire River Valley.
He spotted an unusual bulge in the rock wall and cracked it open with a hammer. Then he noticed what had been the rays of a fish fin.
The fossil is a thin, delicate, structure, and ends at the back of the head. “It is basically a 3-D hard water stain,” Maltese said.
Scientists believe the animal’s spine was cartilage. Researchers took 150 hours to free the fossil from surrounding rock.
The fish apparently lived throughout the world. The two other fossils were found in Japan and the United Kingdom, Schumacher said. The casts can be sent to researchers elsewhere in the world.
