Cyrus Crabb is the son of Lee Crabb from the Dinotopia miniseries, portrayed by David Thewlis. He shares many of the characteristics of his father, primarily that he has not accepted Dinotopian ways. He is well known in the miniseries for referring to the dinosaurs as "Scalies", and for his wooden leg, a replacement for his real leg that was bitten off by the "Scalies" when he was "exploring a sacred temple". He also owns an antiques shop in Waterfall City named Crabb's Curios.
He first appeared trying to find sunstones in a Tyrannosaur skull cave, using dynamite. Later, he becomes a friend to the Dolphinbacks David and Karl Scott. He heavily influences Karl's perception of Dinotopia, and also convinces him that his brother is, in a sense "gone".
He is shown to have spent twenty years researching the World Beneath, and for a way out of Dinotopia. He gets Karl to steal a book of a chart of a ship that escaped, and tries to get him to steal a sunstone, sabotaging Karl's boat, while Karl also gives him a rock instead of the Hatchery sunstone. While the dinosaur Zippeau is examining a scroll describing an entrance to the World Beneath known as the Diamond, Cyrus attempts to kill him after he notices the items that Cyrus had stolen.
He is driven out of Waterfall City at one point by Mayor Waldo for scaremongering in court.
Eventually, Cyrus rallies the support of Karl, David, Marion and Zippo in order to find Arthur Denison's journal and escape Waterfall City. He shows them Denison's submersible and then, he Karl and David set off for the World Beneath. They arrive at the south entrance, and discover the Sunstone Cave. Cyrus then turns on the brothers, intending to escape with the sunstones. Frank Scott intercepts and prevents Cyrus from severely injuring Karl, but not from shooting him in the leg with an old flintlock pistol. Cyrus escapes the cave, but then realizes that Karl took the sunstone used to power the submarine out of the engine. In desperation, he tries to fit another sunstone in, while the submersible begins to leak, his own pistol contributing by partially cracking the glass. Cyrus desperately tries to regain control, until the Fish, the cave's guardian, arrives and kills him by charging at, and swallowing the submersible. Karl sees his wooden leg float to the surface.