We now have some solid evidence that ticks really did suck
the blood of dinosaurs – something scientists and sci-fi writers have
previously suspected – thanks to the discovery of a 99 million-year-old piece
of Burmese amber. Inside the amber, researchers found a hard tick grasping a
feather, thought to be from one of the feathered dinosaurs of the Cretaceous
period, 145 to 66 million years ago. It's very rare to find fossils of
blood-sucking bugs preserved alongside whatever they fed on, and this is the
oldest such sample to be discovered yet, putting ticks and feathered dinosaurs
in the same time frame and confirming the feeding link between them. "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," says lead
researcher Enrique Peñalver, from the Spanish Geological Survey (IGME). If
you've seen Jurassic Park, you'll know that the movie shows dinosaur DNA being
recovered from a mosquito encased in amber. We know ticks, mosquitoes, and
other blood suckers were around at the time of the dinosaurs, thanks to the way
some of them have been preserved by getting trapped in tree sap, but the
question has remained about what exactly they have fed on. Dinosaurs were
probably included in their blood diet, based on what we know about the bugs of
today, but up until now this was just a hypothesis. The new discovery puts
feathered dino remains and a tick in the same block of amber, which means the
link is now confirmed, even if Jurassic (or Cretaceous) Park remains an
impossibility – amber just doesn't preserve DNA well enough for that. Studied
tick pieces and extant 5mm hard tick for comparison. (Penalver et al., Nature
Communications) Even if a dinosaur theme park is still out of the question
though, the findings can teach us more about the mammals and insects living on
Earth some 100 million years ago. "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," says
one of the researchers, Ricardo Pérez-de la Fuente from the Oxford University
Museum of Natural History in the UK. "So although we can't be sure what
kind of dinosaur the tick was feeding on, the mid-Cretaceous age of the Burmese
amber confirms that the feather certainly did not belong to a modern bird, as
these appeared much later in theropod evolution according to current fossil and
molecular evidence."
In another block of amber, the researchers identified a new
species of tick they're calling Deinocroton draculi, or "Dracula's
terrible tick", but here the link to dinosaur blood is indirect – while
the bug is engorged on blood, it's impossible to determine from which animal it
is. The fact that two of these ticks were preserved together with evidence of
hair, however, suggests these were dinosaur blood-suckers as well – no mammal
hairs have ever been found in Cretaceous amber, so we're probably looking at
feathered dinosaurs again. It's an incredible find, all made possible because
of the preserving qualities of amber, and showing dinosaurs really did have
annoying blood-sucking parasites to worry about.
"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," says one of the team, David Grimaldi of the
American Museum of Natural History in New York.
Source : Nature Communications
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