The newly discovered Spiclypeus Shipporum and the Machairoceraptops Cronusi species in Montana and Utah respectively have allowed scientists to learn more about the family of Ceratopsian, which is comprised of horned herbivorous dinosaurs that roamed the earth during the Cretaceous.

Both species had beaks as mouths and spikes on their foreheads, and much like the widely known Triceratops, they also had a shielding bone structure on the back of their skulls.

The Machairoceraptops Cronusi was unearthed from the Wahweap Formation in the Grand Staircase-Escalante National Monument and the Spiclypeus Shipporum from the Judith River Formation in Montana.

The newly discovered species of the family of Ceratopsian, much like the Triceratops, they had a shielding bone structure on the back of their skulls. Photo credit: Biology Pop
The newly discovered species of the family of Ceratopsian, much like the Triceratops, they had a shielding bone structure on the back of their skulls. Photo credit: Biology Pop

Horned herbivorous giants

Although both species belong to the same family of Ceratopsia, they are not closely related. The Machairoceraptops being a Centrosaurine and the Spiclypeus a Chasmosaurine. Species coming from the Chasmosaurine lineage had longer horns on their brows while Centrosaurine species had shorter brow horns with spines circling their crown. The iconic Triceratops is a specimen from the Chasmosaurine branch.

Although scientists are not yet sure why di Ceratopsian dinosaurs had horns and frills, the most widely-discussed theory is that they used these structures to defend themselves against predators, specifically the Tyrannosaurus, as a Triceratops fossil was found with a bitten horn and Tyrannosaurus tooth marks.

Dinosaurs from the Ceratopsia family are known to have originated in Asia due to the oldest fossils being found in that continent. Many fossils have also been found in North America, thus implying that the dinosaurs probably migrated along the Bering Strait in the mid-Cretaceous period.

Spiclypeus Shipporum and Machairoceraptops Cronusi

The Spiclypeus Shipporum gets is lineage name from the Shipp family, who owned the land in the proximity of Winifred, Montana, where the fossil was discovered. The horns of the Spiclypeus Shipporum point to the sides rather than the front. The specimen seemed to have undergone severe bone infection and arthritis; paleontologist are not yet sure how the bone became infected but they theorize that it rendered the dinosaur unable to walk, causing it to die from predators or starvation.

The fossil found in Montana was the first and only species of Spiclypeus that has been found to date. Its name refers to the Latin words for shield and spike. Over half of the dinosaur’s skull was found among the remains, showing its wrinkled nose bone and six frill horns. The cause of the specimen’s death is theorized to be due to a confrontation with a rival dinosaur; it appears that the unearthed Spiclypeus was at least ten years old.

On the other hand, the Machairoceraptops Cronus was found by researchers from Ohio University and the Natural History Museum of Utah, who managed to find a large portion of the skull in the excavation. These species are estimated to have been at least eight meters long, sporting a weight of two tons.

The discovery of these species is significant for the scientific understanding of the ceratopsid dinosaurs, as most of the confirmed fossils have been found in the northern part of the country. Finding the Machairoceraptops Cronus in Utah allowed paleontologists to confirm that ceratopsid dinosaurs were able to reach the southern hemisphere of the United States, providing information on a 4 million year evolutionary gap that remained hidden up to this day.

Source: PLOS One