Paleo Profile: Spain’s High-Spined Herbivore

A restoration of the sail-backed dinosaur Morelladon. Art by Carlos de Miguel Chaves.
A restoration of the sail-backed dinosaur Morelladon. Art by Carlos de Miguel Chaves.

Sail backs were all the rage back in the Mesozoic. Some spinosaurs had them, with Spinosaurus itself bearing one of the most ornate of all, as well as the herbivorous Ouranosaurus, the shark-finned Concavenator, and the strange Deinocheirus, among others. And now, thanks to paleontologist José Miguel Gasulla and colleagues, another high-spined dinosaur has joined the club.

The Early Cretaceous herbivore, named Morelladon beltrani, didn’t have the most ornate ornament of the various sailbacks. The tall spines would have given it more of a high, narrow bump, superficially similar to the midline ridge of the carnivorous Acrocanthosaurus that was terrorizing North America around the same time.

What has continued to puzzle paleontologists, however, is why so many lineages of dinosaurs repeatedly evolved tall backs. No one knows for sure. The answer isn’t environmental, as high-spined dinosaurs lived in disparate habitats, and hot-running dinosaurs did not require sails to heat up, as early hypotheses supposed. The frontrunner right now is that they evolved for decoration, either to impress potential mates, intimidate rivals, or help members of the same species identify each other at a distance.

The latter possibility might be a good fit for Morelladon. During the Early Cretaceous, Gasulla and colleagues write, the Iberian Peninsula was home to a diverse group of dinosaurs that were variations on the theme of Iguanodon. They were so similar to each other that paleontologists have only just started to recognize how many different species and genera there were within a collection of bones that used to bear the Iguanodon title, and so it may be that the high spines of Morelladon helped the dinosaur stick with its own kind and avoid embarrassing encounters like approaching the wrong species come mating season.

The high spines of Morelladon. From Gasulla et al., 2015.
The high spines of Morelladon. From Gasulla et al., 2015.

Fossil Facts

Name: Morelladon beltrani

Meaning: Morelladon means “Morella tooth” in reference to the place the dinosaur was found, and beltrani honors Victor Beltrán “for his involvement and collaboration in the localization of the different fossil sites at the Mas de la Parreta Quarry.”

Age: Around 125 million years old.

Where in the world?: Castellón, eastern Spain.

What sort of critter?: An ornithopod dinosaur related to Iguanodon.

Size: About 20 feet long, similar to its relative Mantellisaurus.

How much of the creature’s body is known?: A tooth, six nearly-complete vertebrae and additional fragments of spine, the sacrum, most of the hips, a tibia, rib fragments, and two chevrons.

Reference:

Gasulla, J., Escaso, F., Narváez, I., Ortega, F., Sanz, J. 2015. A new sail-backed styracosternan (Dinosauria: Ornithopoda) from the Early Cretaceous of Morella, Spain. PLOS ONE. doi:10.1371/journal.pone.0144167

Previous Paleo Profiles:

The Unfortunate Dragon
The Cross Lizard
The South China Lizard
Zhenyuan Sun’s dragon
The Fascinating Scrap
The Sloth Claw
The Hefty Kangaroo
Mathison’s Fox
Scar Face
The Rain-Maker Lizard
“Lightning Claw”
The Ancient Agama
The Hell-Hound
The Cutting Shears of Kimbeto Wash
The False Moose
“Miss Piggy” the Prehistoric Turtle
Mexico’s “Bird Mimic”
The Greatest Auk
Catalonia’s Little Ape
Pakistan’s Butterfly-Faced Beast
The Head of the Devil
Spain’s Megatoothed Croc
The Smoke Hill Bird
The Vereda Hilarco Beast
The North’s Sailback
Amidala’s Strange Horn
The Northern Mantis Shrimp

4 thoughts on “Paleo Profile: Spain’s High-Spined Herbivore

  1. Hello all,

    Personally I suspect that the reason so many prehistoric creatures had dorsal sails was essentially to keep predators from jumping onto their backs! This “leap and lacerate” method was used by many ferocious theropods in order to sharply bite their victim’s neck, piercing vital veins or arteries which would have swiftly killed their prey. The presence of strong, spiny dorsal sails would have prevented such lethal attacks and would have probably intimidated predators as well, as the sails did indeed give the impression of greater corporal volume.

  2. It seems most of these critters lived in or around water. This applies to the sailfinned lizard and basilisk today as well.

    IMO the sail is a locomotive device for moving in water. This also explains why Spinosaurus has the biggest sail of all-it’s the most aquatic.

  3. Mary, I think sails evolved to intimidate enemies not repel them. I’m not aware of any evidence that theropods leaped onto the backs of prey. It’s noteworthy that Spinosaurus was the only known spinosaur with the sail. Unlike its close relatives Spinosaurus was quadrupedal, hence lower and–without the sail–more vulnerable looking. Greater height, conferred by the sail, compensated for a lower stance. K. Carpenter suggested Stegosaurus plates evolved for the same reason. Spinosaurus clearly needed means to deal with enemies as it faced the big Carcharodontosaurus. While Stegosaurus had plates for intimidation, it had a thagomizer as a real weapon if the facade failed. Likewise Ouranosaurus and Morelladon had thumb spikes in case their sails failed to prevent attack.

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