No dinosaur stands alone. Every time a new species is announced, that dinosaur is placed into the context of all that have come before. It's another evolutionary branch that helps us better understand the shape of the dinosaur family tree. And sometimes, when new dinosaurs emerge, they have unexpected connections.

Earlier this month paleontologist Rafael Royo-Torres and colleagues described a new sauropod dinosaur found in the roughly 135 million year old strata of eastern Utah. The jumble of bones recovered from the site includes most of the species' skeleton, including an articulated foot that hints this dinosaur might have wound up literally stuck in the mud. The researchers have named the dinosaur Mierasaurus bobyoungi. But what's surprising about this dinosaur, Royo-Torres and colleagues suggest, is that it has connections to sauropods that lived far away in space and time.

Mierasaurus is a turiasaur. I know that's not a household name, but stay with me for a second. Turiasaurs were a particular group of sauropod dinosaurs known only from the Late Jurassic rocks of Europe. Yet Mierasaurus - as well as the recently-named Moabosaurus - appear to be members of this group that lived in the Cretaceous of North America.

This surprise has some broad implications for how sauropods evolved and moved around the planet. Maybe there are other, older turiasaurs in North America that have gone unrecognized because no one thought they were on the continent. Or, as Royo-Torres and colleagues write, the Utah skeletons might document that this peculiar group of herbivores found a refuge in North America while going extinct in Europe. Either way, the dinosaurs had to wind up in North America somehow, and this will undoubtedly send experts back to museum collections and outcrops to track how a group that was thought to be strictly European wound up in Grand County, Utah. Chalk up another dinosaur and a whole bunch of questions.

Postcranial bones from Mierasaurus. Credit: Royo-Torres et al 2017

Fossil Facts

Name: Mierasaurus bobyoungi

Meaning: Mierasaurus is named for 18th century explorer Bernardo de Miera y Pacheco, "the first European scientist to enter what is now Utah." The species name bobyoungi is in honor of paleontologist Bob Young.

Age: Cretaceous, about 135 million years ago.

Where in the world?: Grand County, Utah. 

What sort of organism?: A sauropod dinosaur.

How much of the organism’s is known?: A partial skeleton and referred isolated bones including a lower jaw and femur.


Royo-Torres, R., Upchurch, P., Kirkland, J., DeBlieux, D., Foster, J., Cobos, A., Alcala, L. 2017. Descendants of the Jurassic turiasaurs from Iberia found refuge in the Early Cretaceous of western USA. Scientific Reports. doi: 10.1038/s41598-017-14677-2

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
The Hiding Hunter
The Horned Lizard
The Silk Bird
The Sieve-Toothed Plesiosaur
The Defenseless Snout
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The Older One From Melksham
The King of the Miocene Iberian Giraffes