Aged dinosaur
Fossils discovered in NM may represent oldest horned dinosaur, museum says
Anew type of horned dinosaur, whose 82-million-year-old fossilized remains were found near Cuba in 1993, is believed to be the oldest representative of all the horned dinosaurs that have yet been discovered, said Spencer Lucas, curator of paleontology at the New Mexico Museum of Natural History and Science.
The dinosaur has been named Menefeeratops sealeyi, after the Cretaceous rocks of the Menefee Formation, where the fossils were found, and in honor of Paul Sealey, the museum’s research associate who discovered them.
The fossils are expected to be put on display in the museum by late summer, Lucas said.
The newly named ceratopsid dinosaur, a large rhinoceros-like herbivore, was related to the better known triceratops, but at about 15 feet long was half the size.
“There’s a whole group of these horned dinosaurs, and Menefeeratops is basically the most primitive member,” Lucas said Wednesday. “Think of a diagram of an evolutionary tree for the horned dinosaurs, and this one is at the base of that evolutionary tree.”
Sealey discovered the fossilized bones in 1993, and the area was more thoroughly excavated in 1996. The remains have subsequently been studied by teams of scientists from New Mexico and Pennsylvania. The results of those studies and the conclusion that it was a newly described type of ceratopsid were recently published in PalZ (Paläontologische Zeitschrift), an internationally distributed peerreviewed scientific journal based in Germany.
Lucas estimates that no more than about 40% of the fossilized animal was recovered. “We have the lower jaw and parts of the backbone and limbs, but the important thing is, we have a lot of the skull,” he said. That’s significant because the skull is what paleontologists rely on to distinguish the differences among the different species of dinosaurs.
“We know from the rocks that the body was washed along by a river, so it may be that parts of it were lost to the river, and of course you can always speculate that scavengers may have consumed other parts, but we still got a lot of it,” Lucas said.
From the time the fossils were discovered 28 years ago, researchers suspected they came from some type of horned dinosaur, “but we knew a lot less about these kinds of dinosaurs than we know now, thanks to the work of a many paleontologists,” he said.
“What that shows is our understanding of the fossils we collect changes over time, so a lot of them that are now sitting in museum drawers and that people may think are not particularly important, can later become much more important, given our changing understanding,” Lucas
said.
Besides, 28 years isn’t even the blink of an eye in geologic time.
When Menefeeratops voraciously chomped its way through the area more than 80 million years ago, “this was a true greenhouse world, with no icecaps and a very high sea level,” Lucas said. North America was cut in half by an inland sea. The eastern part of what is now New Mexico was under water, and the western part was a hot, wet, tropical jungle.
In fact, Lucas said, New Mexico at the time was probably located near the latitude where southern Mexico or northern Central America currently sits.
It was at the juncture of luck, erosion and practiced observation that Sealey happened upon the fossils near Cuba. Armed with geologic maps and information from a museum colleague about previous bones found in the Menefee, “it didn’t take me long when I ran into about 11 bones that were eroding out of the ground,” Sealey said. “I knew it was important,” and he thought, based on the age of the bones and the geology, that it could be something new.
Sealey, 68, a native New Mexican, has been collecting fossils since he was 16. Including the Menefee fossil, he has discovered four new species of dinosaurs, three of which were named for him. His previous findings included a member of the tyrannosaur family, another in the ceratopsian family, and one in the pachycephalosaurus dome-skulled dinosaur family. He also had an alligatoroid he discovered in the Menefee named for him. Except for the fossils found near Cuba, the others were discovered in the Bisti/De-Na-Zin badlands area in northwest New Mexico.
“You know, having a dinosaur named after you is still exciting, no matter how many times it happens,” he said.