Sometimes paleontologists look at dinosaur bones in the ground and immediately know they've found a new species. An unusual flange of bone, a part of a skull, or other piece can give away something never seen before. But, just as often, new dinosaur species remain hidden in museum collections, waiting for new discoveries to put them into context and new eyes to detect their presence. And there are times when new finds and previously-collected fossils come together to reveal a new dinosaur. That's what happened with Latenivenatrix.

In 2014, paleontology graduate student Aaron van der Reest found the hips of a theropod dinosaur in Alberta's Dinosaur Provincial Park. This was already a significant find. The park is famous for its large dinosaur skeletons and bonebeds, but smaller species are rare. But when van der Reest and advisor Phil Currie set about comparing the hip bones to other theropod fossils, they not only found that this dinosaur was new, but that an old dinosaur name might be valid again.

The taxonomic tale is a little complicated. It involves a dinosaur that's everywhere and nowhere. For decades, paleontologists have been assigning various bones and teeth from Alaska to the Four Corners to a raptor-like dinosaur called Troodon. It's unusual for one dinosaur to have such a wide range, however, and in recent years some of these "Troodon" fossils have turned out to be new species - like Talos from southern Utah.

Latenivenatrix differs enough from previously-identified "Troodon" material to be something new. Aside from anatomical particulars, the dinosaur is substantially larger than its relatives - nearly twelve feet long. And the analysis of this fossil changed something else.

The name "Troodon" was based on an isolated tooth that isn't diagnostic. That makes the name basically useless, as other experts had pointed out before. And because there's a second, smaller relative of Latenivenatrix in the same formation, van der Reest and Currie suggest returning to a name based on bones that had been out of fashion since the 80s - Stenonychosaurus.

There's still some untangling to do. Even though "Troodon" isn't a useful name now, it might be if someone eventually finds a unique skeleton that matches that original tooth. And Troodontidae is still used as the name for this dinosaur family even if the name "Troodon" is on extended suspension. Still, the new study marks a turning point for understanding these rare theropods. In one study, van der Reest and Currie named Latenivenatrix, sunk "Troodon", and resurrected Stenonychosaurus, underscoring the point that we still have a lot to learn about this peculiar family of dinosaurs.

A composite reconstruction of Latenivenatrix. Credit: van der Reest and Currie 2017

Fossil Facts

Name: Latenivenatrix mcmasterae

Meaning: Latenivenatrix means "hiding hunter", while mcmasterae is in honor of van der Reest's late mother.

Age: Cretaceous, around 75 million years old.

Where in the world?: Dinosaur Provincial Park, Canada.

What sort of organism?: An troodontid dinosaur.

How much of the organism’s is known?: A partial skeleton and additional specimens of the skull, hips, and limbs..


van der Reest, A., Currie, P. 2017. Troodontids (Theropoda) from the Dinosaur Park Formation, Alberta, with a description of a unique new taxon: implications for deinonychosaur diversity in North America. Canadian Journal of Earth Sciences. doi: 10.1139/cjes-2017-0031

Previous Paleo Profiles:

The Light-Footed Lizard
The Maoming Cat
Knight’s Egyptian Bat
The La Luna Snake
The Rio do Rasto Tooth
Bob Weir's Otter
Egypt's Canine Beast
The Vastan Mine Tapir
Pangu's Wing
The Dawn Megamouth
The Genga Lizard
The Micro Lion
The Mystery Titanosaur
The Echo Hunter
The Lo Hueco Titan
The Three-Branched Cicada
The Monster of Minden
The Pig-Footed Bandicoot
Hayden's Rattlesnake Demon
The Evasive Ostrich Seer
The Paradoxical Mega Shark
The Tiny Beardogs
The Armored Fish King
North America's Pangolin
The Invisible-Tusked Elephant
The Mud Dragon
The Spike-Toothed Salmon
The Dream Coast Crocodile
Buriol's Robber
Ozimek's Flyer
The Northern Naustoceratopsian
The High Arctic Flyer
The Tomatillo From the End of the World
The Short-Faced Hyena
The Mighty Traveler from Egg Mountain
Keilhau's Ichthyosaur
Mexico's Ancient Horned Face
Mauricio Fernández's Plesiosaur
New Zealand's Giant Dawn Penguin
The Orange Sea Lion
Mongolia's Ginkgo Cousin
The Geni River Frog
Isabel Berry's Dinosaur
The Whale Caiman
The Moab Lizard
Yang Zhongjian's Lizard
The Little Anubis
The Shuangbai Lizard
The Wyvern Dinosaur
The "Need Helmet" Dinosaur
The Jianianhua Dragon
The Liaoning Hunter
The Dalian Lizard
Crompton's Aleodon
Jenkins' Amphibian Serpent From the Chinle
The Large Ancestor Lizard
The Crown Tooth
Currie's Alberta Hunter
The Elephant Bird Mimic
The Crested Thief