SCIENCE LAB SPECIAL : HARDHEADS GIRAFFES

Among ancient giraffes, hardheads had the edge :

The necks of giraffes have long been a textbook example of evolution. The theory goes that as giraffe ancestors competed for food, those with longer necks were able to reach higher leaves, getting a leg - or neck - up over shorter animals.

But a bizarre prehistoric giraffe relative reveals that fighting, in addition to foraging, may have driven early neck evolution.

In a new study, paleontologists described Discokeryx xiexhia, a giraffe ancestor, as having helmet-like headgear and a bulky neck vertebrae.

Discokeryx was adapted to absorb and deliver skull-cracking collisions while wooing mates and vanquishing rivals.

''It shows that giraffe evolution is not just elongating the neck,'' said Jin Meng, a paleontologist at the American Museum of Natural History in New York and co-author of the study.

Dr. Meng and his colleagues discovered the fossils in an outcrop of rock in northeastern China called  the Junggar Basin. While exploring the bone bed in 1996, Dr. Meng stumbled across a hunk of skull. 

He could tell it was a mammalian braincase, but the top was flattened like an iron press.

In recent years, more fossilised material began to surface. According to Dr. Meng, both the creature's teeth and it's inner ear structure were reminiscent of modern giraffes.

They determined that Discokeryx was one of the earliest giraffds, an ancestral group of hoofed mammals that give rise to giraffes. Discokeryx most likely resembled an okapi, a cousin of modern giraffes.

Its neck was long, but nothing like a modern giraffe's, and researchers have yet to pinpoint how the animal's anatomical features connect with its counterparts today. [Jack Tamisiea]