We haven't found all the dinosaurs yet. Not even close. Even at the current breakneck rate of discovery - a new species announced every two weeks ago - we're really only just starting to get a tally on the various "terrible lizards" that used to roam our planet. In fact, even places that have been searched for decades are yielding previously-unknown dinosaurs.

Aepyornithomimus tugrikinensis, one of the latest species to enter the scientific canon, is one such dinosaur. As paleontologist Chinzorig Tsogtbaatar and colleagues describe, the fossils of this Cretaceous creature were found in the Cretaceous Djadokhta Formation of Mongolia. Paleontologists have been working this area for almost 100 years, turning up plenty of ghostly white fossils. Yet Aepyornithomimus is unlike anything found there before.

The dinosaur is only known from a left foot. Nevertheless, the anatomy of those bones show that this dinosaur is an ornithomimid - one of the ostrich-like "bird mimic" dinosaurs - that are extremely rare in these fossil beds. It's only the third specimen of these dinosaurs found in the area. More than that, the bones don't match any previously-known dinosaur. This foot, Tsogtbaatar and coauthors propose, belongs to a new dinosaur that padded around the ancient desert and justify the title Aepyornithomimus for its resemblance to the bones of the extinct, flightless elephant bird. 

It's not as if the fossil record is unlimited. It's only a fraction of a fraction of a fraction of all life that ever existed, and there may come a point in the distant future where paleontological wellsprings start to run dry. For now, though, finds like Aepyornithomimus remind us that we're lucky to have any fossils at all, and that even classic localities paleontologists know like the backs of their hands can still offer surprises. 

Foot bones of Aepyornithomimus. Credit: Tsogtbaatar et al. 2017

Fossil Facts

Name: Aepyornithomimus tugrikinensis

Meaning: Aepyornithomimus means "elephant bird mimic", while tugrikinensis refers to the area of Mongolia the fossils were found in.

Age: Cretaceous, between 83 and 72 million years old.

Where in the world?: Central Sayr, Mongolia.

What sort of organism?: An ornithomimid dinosaur.

How much of the organism’s is known?: An articulated left foot.


Tsogtbaatar, C., Kobayashi, Y., Khishigjav, T., Currie, P., Watabe, M., Rinchen, B. 2017. First ornithomimid (Theropoda, Ornithomimosauria) from the Upper Cretaceous Djadokhta Formation of Tögrögiin Shiree, Mongolia. Scientific Reports. doi: 10.1038/s41598-017-05272-6

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