New species of sawfly described

Yale College junior Leah Mock did fieldwork in a remote quarry in western Colorado that exposes the 50-million-year-old Green River Formation.

Inspired by her work in the quarry, Mock described a new species of sawfly, Anoplonyx rasnitsyni, found by Dick King and gifted to the museum by Jim Barkley. She published her findings with André Nel and Mathieu Boderau of the Institut de Systématique, Évolution, Biodiversité in Paris, France, in the journal Mesozoic.

Sawflies are a type of hymenopteran (the group of insects that includes wasps, bees and ants). This new species of sawfly is distinguished from others by a tiny vertical vein in the scaffolding of the wing and some details of its antennae only evident under the microscope. "The details are so minute. You have to pay attention to what's being preserved," said Mock, who is majoring in earth and planetary sciences with a concentration in paleontology and geobiology.

During the Eocene Epoch, the Green River Formation was deposited as a series of lakes located between several mountains. The discovery of this species of sawfly improved our understanding of animal diversity in that environment, Mock explained.

Mock, a New Haven resident, has long been fascinated by the natural world. She became involved with the Peabody in high school through the EVOLUTIONS program. She has worked in the Peabody's Invertebrate Paleontology division since graduating from high school and has conducted research in the museum's Entomology Division, studying parasites that lived inside other insects.

While researching, Mock found this sawfly specimen, one of over 15,000 Green River Formation specimens housed in the Peabody's collection. The detailed preservation of the sawfly, which was complete except for the legs, sparked her curiosity. "I didn't necessarily think this was a new species. I wanted to know what it was," Mock said.

She reached out to the researchers in Paris and sent images of several specimens for review, including the sawfly. "Nel looked at the sawfly and said, 'This seems different than what we've seen in the fossil record,'" Mock said.

Working with Nel and Boderau, she gained experience writing taxonomic descriptions, the meticulous process of identifying all of the features that differentiate this specimen from other known species. "It was almost like learning a new language," Mock said.

"One of the great things about Yale is that students conduct research on some of the millions of fossils in our collections. Sometimes, that work also takes them into the field to collect new specimens and understand the geological context," said Susan Butts, the Peabody's director of collections and research.

Graduate school is in Mock's future, hopefully at an institution with diverse collections to explore. Paleontology is always going to be Mock's passion, and she is drawn to the study of ecosystem engineering, which is how organisms change their environments. "I am interested in questions about the coevolution of life and Earth—how Earth's processes have affected the evolution of life and how the evolution of life affected the Earth," she said.