Science: Update

A PARROT that lived more than 70 million years ago has proven that modern-looking birds were flying around at the same time as pterodactyls soared in the skies.

The fossil of the parrot, which has languished as an unclassified museum specimen for 40 years, has been identified as the earliest example of a land-dwelling bird.

Only the fused jawbone or "symphysis" of the bird has survived but it was enough for Thomas Stidham, of the University of California, Berkeley, to make the identification. "This symphysis appears to represent the oldest known parrot and is, to my knowledge, the first known fossil of a terrestrial modern bird group from the Cretaceous [which ended 65 million years ago]," he reports in the journal Nature.

He found the fossil in the university's Museum of Palaeontology about three years ago. "It had the identification `Aves' [bird] in pencil on the label," Dr Stidham said. "Since parrots were present in the Cretaceous, they must have survived the extinction that killed off the non-avian dinosaurs." The finding means that many modern-looking birds must have lived alongside dinosaurs and not, as many biologists believed, largely evolved as a result of the dinosaur becoming extinct about 65 million years ago.

BLIND PEOPLE can be helped to "see" by devices which beam electronic images directly to their retinas, according to doctors at Johns Hopkins Hospital in Baltimore, Maryland. A group of 15 patients with retinitis pigmentosa - in which the rods and cones that sense light degenerate - took part in a trial in which the nerve cells behind the retina were stimulated directly. The early tests were simple - using a five-by-five matrix of electrodes - but were enough for the patients to recognise simple computer- generated numbers, letters and basic shapes. "It was just like switching a light on," said Harold Churchey, 71, who has been blind for 15 years.

BRAIN SIZE isn't about how clever you are, it's about how well you see, according to Robert Barton of the University of Durham. He studied the brain in 45 primate species and found that the varying size was mainly in areas involved in vision. In the Proceedings of the Royal Society he notes that the parts of the brain that detect colour and pattern are disproportionately large in some primates. This agrees with the finding that brain size correlates with the size of a primate's social group, though the arguments continue as to which factor was the driver of brain growth.

ADULT HEIGHT appears to be determined mostly by a single gene, reports a team at the Medical College of Virginia in Richmond. Studies of twins and people with an abnormality that gives them three sex chromosomes found that the "phog" gene accounts for 78 per cent of the variation in people's height. The likely explanation is that the protein produced by "phog" regulates the performance of other genes in bone-growing cells. Data from the twins study suggests that "phog" may control pubescent growth spurts.