In the journal Nature, a group of Chinese scientists report and describe several fossils of giant fleas. Actually, the largest of the giant fleas is only about 2 cm in length. Compared to our modern fleas, which are half that size, these fleas are giants. The flea fossils are dated about 160 million years ago. It is not certain what they used as hosts, but it may have been large dinosaurs. The giant fleas are flattened side to side like our modern fleas. However, the hind legs are not modified for jumping. The giant fleas likely crawled from host to host.
The giant fleas more closely resemble scorpion flies than do modern fleas. Fleas are most closely related to scorpion flies and true flies. These fossils provide additional data to help establish the flea lineage.