Lice put bite on T-Rex relatives

Lice may have been feeding off the blood of Tyrannosaurus Rex’s feathered relatives more than 65 million years ago, scientists believe. New evidence suggests early forms of the insects had evolved before the extinction of the dinosaurs.

If so, they might well have plagued dinosaur species which sported primitive feathers.

The US research, based on fossil and molecular data, is published in the Royal Society journal Biology Letters.

“Our analysis suggests that both bird and mammal lice began to diversify before the mass extinction of dinosaurs,” said study leader Kevin Johnson, from the University of Illinois at Urbana-Champaign.

“And given how widespread lice are on birds, in particular, and also to some extent on mammals, they probably existed on a wide variety of hosts in the past, possibly including dinosaurs.”

Present-day birds are widely believed to be descended from carnivorous two-legged “theropod” dinosaurs such as Tyrannosaurus Rex, some of which are known to have been feathered. They may also have inherited their lice, Dr Johnson believes. The research also lends support to the theory that major groups of birds and mammals had already appeared before dinosaurs vanished. The “terrible lizards” are thought to have been killed off by a giant meteorite that smashed into the earth 65 million years ago.

Dr Johnson’s team built a partial family tree of lice by comparing the DNA sequences of genes from 69 present-day louse lineages.

The way changes in gene DNA accumulate over millennia can be used to create a “timeline” of the evolution of related groups of organisms.

Knowing how lice have evolved also provides clues about the evolution of the hosts they have fed upon. Lice are specialists that adapt themselves to particular hosts, whether they are feathered or furry. A fossil described by scientists in 2004 showed that lice much like those living today were around 44 million years ago.