Photo Courtesy of Deb Labonte
By Anoushka Kuswaha ’24 & Yuyang Wang ’24
Science & Environment Editor | Staff Writer
Mount Holyoke College Professor of Geology Mark McMenamin and his wife, Dianna McMenamin, found a dinosaur bone fossil in the parking lot of the Newman Center in Amherst, Massachusetts, in August 2021.
“We found it on our 40th anniversary, August 8,” McMenamin said. “Dianna does a lot of work making our garden beautiful, and she saw some stones that were … in the dirt, and she wanted to take them home. So, we’re picking up all these stones and rocks and putting them in the back of our car. And one of them was [the] bone of the dinosaur,” McMenamin recalled.
The place where the fossil was found was originally part of the Portland Formation of the Hartford Basin in western Massachusetts. This rift valley runs all the way from Vermont, New Hampshire, all the way down to Connecticut. According to McMenamin, the unique process of the Hartford basin’s formation makes it a perfect place for fossils to be preserved. “Mostly we know about the dinosaur tracks because they’re really well preserved. But the bones have been very hard to find, and we have very, very few of them. [This discovery is] one more piece of evidence about the dinosaurs that were alive — not just their tracks, but their actual remains,” McMenamin said.
The fossil itself is a gray, almost black-colored fossil bone. McMenamin identified the fossil as “the distal, [the] outer, end of the right humerus, the long upper arm, of a large neotheropod,” according to an article about the fossil discovery by Current Science Daily. In an interview with Mount Holyoke News, McMenamin explained that he was able to initially identify the fossil as being the humerus bone of the neotheropod due to the fossil’s “roughly triangular shape” and the fact that “one end [of the fossil] seems to be where the shaft of the bone comes out.” McMenamin went on to confirm his hypothesis that the fossil was in fact a bone through the removal of a small piece of the fossil for scanning in a Scanning Electron Microscope in his laboratory at Mount Holyoke College. The scan results “came up with both [a] phosphorus and [a] calcium peak. So that confirms it as [a] fossil bone,” McMenamin explained.
After successfully identifying the item as a fossil bone, McMenamin “went into the literature,” reading earlier studies in order to find previously discovered “examples of bones of similar shape.” He observed that several discoveries were made of dinosaurs from the early Jurassic period that had preserved humeri that were “broken off in just the same way.” McMenamin identified one genus of large theropod dinosaur discovered in Antarctica, Cryolophosaurus, as having humeri fossils that “look like a pretty good comparison” to the one he discovered.
However, he emphasized that the fossil he discovered is only a partial fossil, “so interpretations could be changed.” Based on comparisons with other early Jurassic period dinosaur fossils, such as those of the similar Dilophosaurus genus, McMenamin was able to conclude that the fossil belonged to a “very large animal.” He estimated that the neotherpod would have been more than 30 feet long, around nine meters.
The dinosaur itself is understood to have been a predatory dinosaur based on McMenamin’s current work with the fossil, particularly with his comparisons to fossils of the Dilophosaurus and Cryolophosaurus genera. McMenamin observed that the dinosaur “has a very dense bone structure, which is oftentimes seen in dinosaurs that spent a lot of time in the water.” Thus, he has drawn the tentative conclusion that the fossil belonged to a swimming dinosaur that was also capable of walking, and most importantly, hunting on land. This conclusion is further supported by “trace fossil evidence … [of] kick marks, in the … strata formed by the hind limbs of a swimming dinosaur,” as well as “large footprints from an unknown animal walking on dry land” in the area surrounding the location where the fossil was found, McMenamin stated.
At present, further investigation and discovery are required in order to completely confirm the theories about the creature’s species, genus and lifestyle habits. Regarding the challenges waiting ahead in the discovery process of this creature, McMenamin expressed that “the best thing … would be to find a more complete skeleton.” McMenamin’s individual searches in the surrounding areas thus far have been unsuccessful in retrieving more of the neotheropod’s complete fossilized skeleton. McMenamin said that there will be opportunities for students at Mount Holyoke College to assist in the further discovery of this dinosaur’s skeleton, and that “there’s a lot more research to do.”
McMenamin remains optimistic that more of the creature will be found, and that the fossil discovery will have a positive impact on current knowledge about the Jurassic period. McMenamin stated that if all of his current analysis and observations are correct, then the fossil bone could have belonged to “one of the largest dinosaurs of its time.” He also estimated that this dinosaur could have been the first dinosaur to have reached its size in the early Jurassic period, “which is still early in dinosaur history.” Forming a conclusion about the dinosaur’s height and lifestyle has the potential to be influential on human knowledge about the early Jurassic period’s ecology and the evolution of height in dinosaurs, McMenamin explained.
Due to the uncertainties associated with any new scientific discovery, the naming of the creature is somewhat in the air. In an effort to pay tribute to the area where the fossil was discovered, McMenamin is hoping to name the dinosaur Massalophosaurus, after the state of Massachusetts. However, he emphasized that the name Massalophosaurus is a nomen nudum, and the official naming of the creature will be decided on after much more research.
The discovery of this fossil comes shortly after the recent naming of Podokesaurus holyokensis, discovered by Mount Holyoke’s Mignon Talbot in 1910, as the first official Massachusetts state dinosaur. The discovery of a potential new species of dinosaur will lend more excitement and interest to “learning about the backstory … of the land that we’re living on here. It has … a fantastically rich history,” McMenamin said.
There also appears to be a connection between these two dinosaurs. McMenamin stated that the dinosaurs “would have been neighbors,” and that both creatures “would have been living in the same environment.” The nature of their relationship, unfortunately for Podokesaurus holyokensis, was likely one between a predator and its prey.
McMenamin expressed that the discovery of dinosaurs is one of the few things that all people on the planet can have in common with one another. He emphasized that there is a lot to learn from paleontology discoveries happening around the world and that we can use that information “to get back to work … learning more about the ancient history and our own local backstory,” all of which will be of “great interest to the entire international scientific community.”