Source: The Guardian

Dinosaurs may have been fearsome and intimidating creatures that dominated the prehistoric earth – but it did not stop them having their feathers ruffled by parasites, researchers have found.

Scientists have discovered ancient pieces of amber, dating from about 99m years ago, that contain dinosaur feathers riddled with louse-like insects. One of the feathers even shows signs of having been nibbled.

The team said it is the first time feather-eating insects have been discovered from that era – despite many non-avian dinosaurs and early birds having been identified as having plumage.

“This is the earliest recorded, or formally documented, [instance of] lice or louse-like insects feeding on feathers,” said Dr Chungkun Shih, a visiting professor at Capital Normal University in China and co-author of the research.

The discovery pushes back the origin of feather-munching insects by about 55m years. They were not the only parasites that might have troubled dinosaurs; previous research has shown that the beasts also endured blood-sucking ticks.

Writing in the journal Nature Communications, Shih and colleagues revealed how they found 10 tiny louse-like insects alongside two dinosaur feathers inside Burmese amber believed to date from about 99m years ago – or possibly earlier.

The team said the insects belonged to a previously unknown species, dubbed Mesophthirus engeli, and were nymphs – an immature stage of insect development. Among their features, the insects had tiny wingless bodies, of 0.14mm–0.23mm in length, strong chewing mouth parts with at least four teeth, and short, sturdy antennae. The team estimate that the insects would have reached about 0.5mm in length in their adult phase.

Shih said the size of the insects was a surprise, since fleas from the era were much larger than their modern counterparts. “Based on our studies of fossil fleas, we thought that if we were looking for lice, the size may be bigger than today’s lice, but [they] turned out to be very small,” he said. “That can explain why on compression fossils [in rocks] we cannot find any lice.”

Even within ancient amber, the insects are rare. Shih said the team looked at up to 1,000 pieces containing preserved bird or dinosaur feathers before making their discovery.

They said the insects in the amber seemed to have been feeding on the feathers, noting that one of the pieces of amber had four insects preserved on the feather, and another five near it, with one of the lice “preserved with its legs tightly hugged [around] a feather barb”. The feather itself shows signs of damage, with holes in the vanes that the team said were consistent with an insect chewing on them.

“This finding demonstrates that feather-feeding behaviours of insects originated at least in the mid-Cretaceous, accompanying the radiation of feathered dinosaurs including early birds,” the authors wrote.

The team said analysis of the two feathers, which were 12.7mm and 13.6mm in length, suggest they were likely to have come from two types of dinosaur, one of which was probably a pennaraptoran – a birdlike theropod – although it is possible that they are two different types of feather from the same species..

“This is the first evidence that a feathered dinosaur actually suffers from a parasite which chews on their feathers,” said Shih.

Michael Benton, professor of vertebrate palaeontology at the University of Bristol, welcomed the study. “It’s amazing, and extra convincing that in a single specimen they find nine lice of the same species, each only a fifth of a millimetre long, clinging on to different parts of the feather trapped in amber,” he said.

The damage to the feathers, he added, showed parallels to that made by modern parasites, with the study suggesting that such insects evolved alongside the development of feathers. “Parasites get going as soon as they have the chance,” he said.

Source: The Guardian