But it wasn't always like that; I knew Knight's painting reflected the view of the theropod as a dynamic, active predator and I wanted to dig into some literature and find where this began. It's not a completely thorough review of every mention of Laelaps, but I think I've dipped into enough from the era to give a good impression of just how dynamic a predatory dinosaur was thought to be. One quick note: I'll use both Dryptosaurus and Laelaps in this post, the former when discussing the modern knowledge about it, the latter when referring to it in a historical context.
As noted in the previous post and its comments, Knight was not an artist who did his own research, as Gregory S. Paul does today. Knight followed the most contemporary knowledge of the paleontological community and his individual patrons, which in this case was Cope. Indeed, in an early account of his work in The American Naturalist, Cope himself would invoke a modern analog when discussing Laelaps when he wrote that the long legs of the dinosaur...
...joined with the massive tail points to a semi erect position like that of the Kangaroos while the lightness and strength of the great femur and tibia are altogether appropriate to great powers of leaping.Hardwicke's Science-Gossip, a short-lived 19th century pop-sci magazine, echoed this in an 1891 story and added a bit of gory detail:
The Laelaps was forty feet long, stood twenty-five feet high on its hindlegs, and was built like a kangaroo. It was the most astonishing jumper that ever existed, with teeth for cutting and sharp claws on the front feet, evidently designed for tearing out its adversary's eyes.Taking it even further, Sir John William Dawson wrote a colorful passage on Laelaps in his 1873 pop-sci book The Story of Earth and Man, culminating with this image:
Had we seen the eagle clawed Laelaps rushing on his prey; throwing his huge bulk perhaps thirty feet through the air, and crushing to the earth under his gigantic talons some feebler Hadrosaur, we should have shudderingly preferred the companionship of modern wolves and tigers to that of those savage and gigantic monsters of the Mesozoic.Dawson accorded Laelaps an even higher standing than mammals, a comparison that would be considered a bit absurd once dinosaurs fell from grace. Even today, when theropods are generally considered to be the "peers" of today's dynamic mammalian predators, few paleontologists would conjure the image of a large one leaping thirty feet.
A more modern look at Dryptosaurus, the artist formerly known as Laelaps. By Frederik Spindler, via Wikimedia Commons.
We now understand Dryptosaurus to be a primitive throwback compared to its more advanced tyrannosaur contemporaries; while the best known Late Cretaceous North American tyrannosaurs are from the west, Dryptosaurus lived on the other side of the Western Interior seaway that split the continent in two, on a land mass called Appalachia. Unlike its western counterpart Laramidia, we have precious few geological windows into this time in the eastern US. Dryptosaurus is an intriguing critter. Why did it preserve more primitive tyrannosaur features? What was its environment like? The Earth's geological processes have unfortunately hidden many of these answers from us, then made the region attractive to human settlement, limiting our access to Mesozoic rock further.
I can't end this without contrasting the taxonomic change of Laelaps to Dryptosaurus with Torosaurus being possibly absorbed into Triceratops. While Scannella and Horner have their work cut out for them if their lumping of the two genera is to be accepted, at least they don't have to deal with the level of rancor that existed between Marsh and Cope. After all, renaming a species because its name is already taken is pretty cut-and-dry, and requires little evidence to justify: just show that it's been given to an organism in the scientific literature, and the matter is settled. But notice that a couple decades after Marsh reassigned it to Dryptosaurus, Knight still chose Cope's original Laelaps for his title.