Groovy teeth, but was Sinornithosaurus a venomous dinosaur?

It's a dinosaur tooth, and clearly one that belonged to a predator - sharp and backwards-pointing. But this particularly tooth, belonging to a small raptor called Sinornithosaurus, has a special feature that's courting a lot controversy. It has a thin groove running down its length, from the root to the very tip. According to a new paper from Enpu Gong of the Chinese Academy of Sciences, it was a channel for venom. Thanks to a certain film that shall remain nameless, a lot of people probably think that we already know that some dinosaurs are venomous. But the idea that Dilophosaurus was armed with poison, much less spat its toxins at its prey, is non-existent. Some scientists had speculated that they were venomous based on their bizarrely notched and allegedly weak jaws. But these notches have since been found in many other species and no one has ever actually measured the strength of Dilophosaurus's jaws. The best sign that a dinosaur was venomous would be the presence of grooved or hollow teeth. With some notable exceptions, most animals with poison bites use grooves like these to channel their toxins from glands in their mouth to whatever they bite. And grooves are exactly what Gong and his colleagues found in Sinornithosaurus's well-preserved skull. Bryan Fry, who discovered venom glands in Komodo dragons earlier this year, says, "It is an absolutely fantastic piece of work. I actually got goose-bumps reading it! Other studies have suggested dinosaurs may be venomous but this is the most solid piece of evidence." Sinornithosaurus (meaning "Chinese bird-lizard") is a small feathered dromaeosaurid (or, more commonly, 'raptor') and an early distant cousin of the birds. Its teeth are unusually large and Gong says that those in the upper jaw are "so long and fang-like that the animal appears to be saber-toothed". They're very similar to the fangs of back-fanged snakes like boomslangs and vine snakes. Gong says that other aspects of the skull in support of his venom hypothesis. His team noticed that Sinornithosaurus has a small hollow on the side of its jawbone that could have housed a venom gland. They also found a thin groove running along the animal's jaw, with small pits at the top of each tooth. They interpret this canal as a "collecting duct" that channelled venom from the gland to the teeth, and each pit could have acted as small, local venom reservoirs. David Burnham, a co-author on the paper, says, "Other fossil animals (dinosaurs, lizards, mammals) have been suggested to be venomous simply on the presence grooved teeth but out work found multiple lines of evidence."