|Sinorthosaurus - with grooved teeth for venom|
The venom-spitting dinosaur in Jurassic Park may have been fictional, but in a great case of life imitating art, scientists have discovered evidence of a real venomous dinosaur that walked the earth in China over 120 million years ago. Sinornithosaurus is the first confirmed venomous dinosaur, but there is evidence that venom is even older than this most recent discovery--that creatures from up to 500 million years ago could also have been venomous. These ancient venomous creatures are giving us reason to believe that, evolutionarily speaking, not being venomous may actually be more noteworthy than being venomous.Venomous dinosaurs? Why not? If you need something dead to eat, venom seems like an obvious way to assist.
David Burnham, a paleontologist at the Kansas University Natural History Museum, was hunting for raptor fossils in rural China when he and his colleagues stumbled across a new fossil skeleton with grooved teeth and an inexplicable gap in its skull. They puzzled over what these two clues could mean. And then one day, while examining the skulls of venomous komodo dragons, it suddenly clicked. The cavities in the raptor skull very closely resembled areas in the komodo dragon skull reserved for their venom glands. Burnham began to wonder, was it possible that this ancient raptor was also venomous?
Most of us tend to think of venom as something unique that only belongs to a small subset of animals. We've certainly never seen a venomous sparrow, so we imagine that venom evolved recently enough to be confined to creatures like reptiles and spiders. The venomous conodont is changing the way we think about the uniqueness of venom among animals. Rather than spontaneously appearing in more modern reptiles, it seems that venom was there all along--and was just lost along several paths of the evolutionary tree, including our own.But what would the Dino Babe's have to say about a poisonous dinosaur?
Burnham sees this idea as a game-changer. He points to our recent revelation that there are far more venomous creatures out there than we previously thought. Just a few years ago there were only 200 species of fish described as venomous. Now there are over 1,200 and counting. Fossils of animals like the conodont and Sinornithosaurus help confirm the growing notion that venom is actually the rule rather than the exception, especially when it comes to more ancient creatures. Instead of asking why a particular species is venomous, Burnham now thinks, "The real question is, why isn't something venomous?"