Ancient Greeks refer in some of their myths to creatures called griffins. These strange beings had the bodies of lions, but the beaks of eagles and were associated with the guarding of treasure. From then on, griffins were used to represent divine power, including in English heraldry.

The griffin as it is typically represented (for example with large wings) never existed. However, it is hypothesised that there may have been a tangible cause for the myths: the stories originated from a time when the Greeks first encountered a nomadic people, the Scythians, who had travelled from areas where protoceratops were found.

Protoceratops were the forerunners of dinosaurs including triceratops which, whilst lacking their famous horns, bore some resemblance to them, and had both a beak-like mouth (and distinctive neck frill) and a body as similar to a lion as anything alive at the time.

Protoceratops skull

A well-preserved protoceratops skull is now heading the dinosaur fossil section of Heritage's January Natural History auction, estimated at $45,000-55,000. It is not distorted, has a fine set of teeth and good bone texture.

The auction has live floor bidding on January 17 2010, but you can put in a bid now over the internet.

Dinosaur fossils can be extremely valuable, with the obvious example being the T. Rex which sold for $5m several weeks ago, but a complete protoceratops skeleton from the same auction sold for $440,000.

In this auction, there are a number of other excellent pieces for a dinosaur collector including some from the protoceratops' descendents: a triceratops horn in great condition, expected to sell for $8,000-10,000, and an exceptionally large leg which is listed at $18,000-22,000.

Triceratops leg (Click to enlarge)

The leg, at a startling 4.5ft tall, would have been a part of a much larger triceratops than any for which a full skeleton has been discovered.

The sale also boasts a long tail from a species of duck-billed hadrosaur, listed at $14,000-18,000. A complete duck-billed dinosaur sold for $458,000 at the T. Rex sale.

There are also a set of veloceraptor eggs ($8,500-10,000). Buyers may be reassured that they are unlikely to hatch like they do in Jurassic Park.

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Images: Heritage Auctions