The newly named trilobite species Flexicalymene trentonensis, which can be found in parts of upstate New York and southeastern Canada.© Melanie Hopkins
In January 2022, Museum Curator Melanie Hopkins was looking through boxes of historic trilobite specimens slated to be included in the Museum’s yet-to-open Louis V. Gerstner, Jr. Collections Core when she noticed something strange.
The labels indicated that the specimens were all the same species, Flexicalymene senaria, a common and often well-preserved trilobite. But to Hopkins’ trained eyes, some of those fossils were different from the others.
“I quickly realized that not all the specimens in the boxes were the same species,” said Hopkins, who is the chair of the Museum’s Division of Paleontology. “So I started reading some of the history of this species, and it turns out that I wasn't the first to notice this.”
Hopkins found that as early as 1842 and as recently as 2002, researchers around the country had questioned whether there was more than one species being catalogued under a single species name.
“For decades, scientists were using the same name for two different species without realizing it, so it became difficult to untangle,” Hopkins said. Further complicating things: there was no original type specimen for Flexicalymene senaria. Type specimens ensure that scientists have a single reference point when referring to a particular organism.
With the help of collaborator Markus Martin, Hopkins examined the existing literature as well as new and historical fossil collections at the Museum, the New York State Museum, Paleontological Research Institution, and the Harvard Museum of Comparative Zoology. The research team also conducted fieldwork in the Mohawk and Black River Valleys of upstate New York.
Their resulting study, published today in the journal American Museum Novitates, gives a name to the new species: Flexicalymene trentonensis. The name was inspired by Trenton Falls, NY, which is close to the quarry where exceptional examples of these trilobites have been found, as well as by the geologic unit in which they are found, the Trenton Group.
Hopkins and Martin’s work also determined the geographic distribution of the new species, and reassessed previously reported patterns of skeletal change. F. senaria is more widespread than F. trentonensis, including across parts of upstate New York, northern Michigan, Virginia, West Virginia, Ontario, and Quebec. F. trentonensis is only found in small patches of upstate New York and Quebec, in places with the species for which it was once confused.