Fossilized grasshopper eggs found at John Day Fossil Beds National Monument/NPS

A clutch of fossilized grasshopper eggs, believed to be the first ever found, has been discovered in John Day Fossil Beds National Monument in Oregon.

As reported in the journal Parks Stewardship Forum, Jaemin Lee (University of California, Berkeley), Dr. Nicholas Famoso (John Day Fossil Beds National Monument), and Angela Lin (University of Oregon) used micro-CT scans to study the internal structure of over 50 fossilized insect eggs and an intact egg pod from the park's Sheep Rock Unit.

The eggs had been previously found in isolation and were identified as ant pupae or ant eggs. The discovery of the intact nest in 2016 resulted in confirmation that these were not made by ants. The shape of the eggs is consistent with modern grasshoppers that lay their eggs in underground nests. Never before has a fossil egg pod of grasshoppers been found and described on Earth, attesting to their rarity and the exceptional preservation of the John Day fossil beds, a park release said.

The fossilized egg pod is named Subterroothecichnus radialis, while the individual eggs are named Curvellipsoentomoolithus laddi. Both names speak to the shape and nature of the trace fossils and egg fossils, but the eggs are named posthumously after the first National Park Service superintendent of John Day Fossil Beds National Monument, Benjamin Ladd. Ladd began the protection and resource management and science programs at the park that study and protect these specimens, which are currently only known from within National Park Service boundaries. 

The new study, “Microtomography of an enigmatic fossil egg clutch from the Oligocene John Day Formation, Oregon, USA, reveals an exquisitely preserved 29-million-year-old fossil grasshopper ootheca,” can be found online in Parks Stewardship Forum: Fossil Grasshopper Eggs