The link does not mention his training, though it can be found in the French version. He studied for a while at Prague's fine arts academy, but was mostly self-taught. Since his father was an architect, he was exposed to illustration techniques while young. That said, his technique changed little over his long career.
He was a very good illustrator with a feeling for action and atmosphere. Wikipedia notes that once his work became known outside Czechoslovakia, it became influential in the field of paleontology illustration.
The images below show that his versatility extended beyond dinosaurs.