Ancient insects similar to modern lice parasitized dinosaurs by feasting on their feathers, as evidenced by a pair of fascinating new amber fossils.
Modern birds are sometimes infested by feather-chewing and feather-feeding lice, and as new research published today in Nature Communications shows, their Mesozoic predecessors had a similar problem.
The new paper, led by paleontologist Dong Ren from the Capital Normal University in Beijing, China, describes a previously unknown louse-like insect, named Mesophthirus engeli, that lived 100 million years ago during the mid-Cretaceous. Ten of these individuals were found in two pieces of Burmese amber—both of which contained damaged feathers. It’s guilt by association, but these feathers certainly appear to have been chewed upon by the bugs. It’s now considered the oldest evidence of feather-chewing in the fossil record.
That dinosaurs were tormented by parasites is hardly a surprise. Dinosaurs living during the Jurassic (201 million to 145 million years ago) and the Cretaceous (145 million to 66 million years ago) were afflicted by blood-sucking fleas, and ticks have parasitized dinos since at least the Cretaceous.
The new discovery is different in that it’s now the earliest example of a feather-chewing insect, the previous record belonging to Megamenopon rasnitsyni—an ancient bird louse fossil found in Germany that dates back some 44 million years to the Eocene, approximately 22 million years after non-avian dinosaurs went extinct. The new discovery now pushes back this parasitic behaviour by another 34 million years, which is a big deal.
“It is very rare and difficult to find these earliest louse-like insects in amber,” Chungkun Shih, a co-author of the new study and a scientist from the National Museum of Natural History at the Smithsonian Institution, wrote in an email to Gizmodo. The discovery is significant, he said, because it’s helping paleontologists to better understand the early evolutionary development of these insects’ physical characteristics and feather-feeding behaviours.
In total, 10 specimens of M. rasnitsyni were spotted in two pieces of amber, both of which were found in Myanmar (formerly Burma) and contain dinosaur feathers. Microscopic analysis of these feathers showed they were partially damaged—the kind of damage you’d expect from parasites capable of chewing through the tough barbs and barbules of a feather.
As Shih explained, the newly described nymph featured a number of characteristics consistent with a parasite, including a “tiny wingless body,” a head with “strong chewing mouthparts,” thick and short antennae with long setae (hair-like structures), and “legs with only one single tarsal claw associated with two additional long setae,” among other features. The bug had “strong chewing mouthparts to feed on the feathers” and “leg claws and setae to climb on and cling to the feathers and avoid being removed by the hosts,” said Shih.
Interestingly, the mid-Cretaceous just happens to coincide with the diversification of birds and other feathered dinosaurs, so the timing makes a lot of sense. These parasites were simply taking full advantage of new opportunities—much to the chagrin of Cretaceous dinosaurs.