Oh, In my point of view when referring to a band being dinosaur means that they are still great, making good music and still rocking nowadays.
Hum...dinosaurs doesn't exist anymore... it's a good point, but dinosaurs are big! Geez, how my english is poor...sorry. many times when it comes to discuss something I feel I don't have the knowledge.
Anyway, dinosaur or not, they still are on the road!