French auctioneer Alexandre Giquello next to an Allosaurus skeleton at the Drouot auction house in Paris on Friday. More than 150 million years old, the rare skeleton of an Allosaurus, one of the oldest dinosaurs and considered by palaeontologists to be the "grandfather" of the legendary T-Rex, will be up for auction on Tuesday at the Drouot Hotel. Almost 10m long and 3.5m high, the Allosaurus skeleton is estimated to fetch between €1 million and €1.2 million (S$1.6 million and S$1.9 million).