Green River Formation Cricket and Cranefly Insect Fossils

The Green River Formation deposits of Wyoming, Colorado, and Utah are best known for their immaculately-preserved fish, but other examples are known as well, as this specimen attests. This is an example of association plaque of a pair of craneflies, and a very detailed cricket. The cricket is most likely Pronemobius sp, possibly Pronemobius smithii, and shows that there has been little change in these insects over the past 45 million years or so. The presence of an ovipositor shows this fossil to have been a female. The craneflies are members of the Limoniidae, a family typically smaller than the the family Tipulidae.