Carnivorous dinosaurs were more plentiful than previously thought, as researchers just tripled the number of known species of such dinos in a single swoop.

Before this week, seven species of small, two-legged meat-eating dinosaurs were documented for western Canada and the United States.

Analysis of a huge data set of fossilized teeth revealed at least 16 additional species, for a total of 23, according to a paper in the latest issue of PLoS ONE.

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“Small meat-eating dinosaur skeletons are exceedingly rare in many parts of the world and, if not for their teeth, would be almost completely unknown,” University of Alberta researcher Derek Larson said in a press release.

“We can identify what meat-eaters lived in what geographic area or geologic age,” His co-author, University of Alberta paleontologist Philip Currie, said.  And we can do this by identifying just their teeth, which are far more common than skeletons.”

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The fossils included samples from members of the families to which Velociraptor and Troodon (thought to be the brainiest dinosaur) belong.

The researchers say the increased count shows that, instead of a few species existing for many millions of years, there were actually many small meat-eating species, each existing for shorter periods of time.

All of this happened 85 to 65 million years ago, not long before non-avian dinosaurs bit the dust. Perhaps many different species evolved for microclimates that rapidly changed after the asteroid strike? Many questions remain about the last days of dinosaurs, and these latest findings appear to thicken the plot.

Image: A Troodon, one of the small carnivores characteristic of Alberta dinosaurs, tries to catch a toothed bird. Credit: Jan Sovak, Calgary