One of the most iconic images from Jurassic Park is that of a mosquito trapped in amber, engorged with dinosaur blood. But while it makes sense that parasites bugged the dinosaurs back in their day, actual evidence has always been lacking: no one has ever actually found a blood-sucker from the “Age of Dinosaurs” preserved alongside dinosaur remains.
Well, step aside, mosquito – a new study in Nature Communications has finally revealed the real deal: a piece of Burmese amber with a tick inside, still grasping onto the feather of its dinosaur host.
Unlike the fictional mosquitoes of Jurassic Park, this tick can’t give us the secrets of dino DNA – in the real world, DNA breaks down far too quickly to survive that long, and no ancient DNA has ever been successfully extracted from amber of any age – but at around 99 million years old, this is by far the oldest evidence of a blood-sucking bug fossilised with the remains of its host. What’s more, birds like we know them today hadn’t evolved at that time, so this feather must have belonged to another group of feathered dinosaurs.
“The fossil record tells us that feathers like the one we have studied were already present on a wide range of theropod dinosaurs, a group which included ground-running forms without flying ability, as well as bird-like dinosaurs capable of powered flight,” said study author Ricardo Pérez-de la Fuente of the Oxford University Museum of Natural History in a press release.
It’s difficult, therefore, to know for certain what kind of dinosaur this tick was climbing around on. Dinosaurs with that style of feather included cassowary-like oviraptorids, predatory dromaeosaurs like Velociraptor, long-gone ancient bird groups like the enantiornithes, and others.
This particular tick belongs to a known species called Cornupalpatum burmanicum, but it apparently wasn’t the only dino-biter around. In the same study, the international team of amber researchers also named a brand new extinct tick species – Deinocroton draculi (you can guess what inspired that name!) – from specimens found in other pieces of amber.
Two of the Deinocroton ticks were found together in the same piece of amber; one other was massively swollen, engorged with blood from a recent meal. Within the same golden nugget were bristles from skin beetles, insects that frequent animal nests to eat loose skin, hair and feathers. Since Burmese amber so commonly contains feathers, the researchers suspect these ticks were congregating around feathery dinosaurs.
“The simultaneous entrapment of two external parasites – the ticks – is extraordinary, and can be best explained if they had a nest-inhabiting ecology as some modern ticks do, living in the host’s nest or in their own nest nearby,” explained study author David Grimaldi of the American Museum of Natural History.
We may not be able to recreate the movies, but discovering cases of ancient parasitism holds exciting possibilities for our understanding of prehistoric animal lifestyles and evolution. For example, how did dinosaurs deal with their parasite problems?
“The most common ectoparasites that you see in birds are feather lice,” said Amanda Falk of Centre College in Kentucky, who wasn’t involved in this research. “Birds will do a number of different behaviours, things like ant-bathing and dust-bathing, to try and cut down on the number of feather lice. [Some birds] will rotate nests every year or couple of years to try and cut back on feather-lice infestations.”
So, might ancient dinosaurs have had similar strategies for avoiding ticks and other pests? And what about diseases? “Ticks are infamous blood-sucking, parasitic organisms, having a tremendous impact on the health of humans, livestock, pets and even wildlife, but until now, clear evidence of their role in deep time has been lacking,” said study author Enrique Peñalver of the Spanish Geological Survey.
Today, ticks are notorious vectors of such pathogens as the bacteria that cause Lyme disease and the viruses that cause Rocky Mountain spotted fever. And, believe it or not, prehistoric diseases have been discovered before! Biting flies in Burmese amber have been identified with internal remnants of microbes associated with diseases such as malaria, leishmaniasis and trypanosomiasis. More parasite discoveries might provide clues to dinosaur diseases.
To answer these and more questions, the researchers are hoping to find more preserved parasites, especially now that they have a sense of what to look for.
The ticks were found in chunks of amber that belonged to private collectors James Zigras and Scott Anderson, who generously donated them to the American Museum of Natural History in New York and the Carnegie Museum of Natural History in Pennsylvania. “[T]his work can be considered a success of the communication between the private collector community and researchers,” Peréz-de la Fuente said via email, “which sadly is not the norm at all in palaeontology!”
But amber might not be the only place to look for parasites. There are fossil sites in places like China that produce birds and other dinosaurs so well preserved that the remains of feathers can be seen clearly surrounding the bones. Could there be ticks and other creepy-crawlies waiting to be found within?
“It’s certainly a possibility if you do get a very rapid death,” Falk said, “like something gets buried in a mudslide because everything on that [dinosaur] would probably die with it. But it all would depend on the circumstances of death, and then what the preservation is going to look like after that.”
That means dinosaur fossils formed under the right conditions to preserve identifiable parasites are probably very rare indeed.
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