A restoration of Xenomeryx by Israel Sánchez.

Paleo Profile: Amidala’s Strange Horn

ByRiley Black
January 01, 2016
4 min read

Fossil mammals don’t get the attention they deserve. If you’ve ever been to the sprawling fossil halls of one of the great eastern museums – the American Museum of Natural History, the Field, the Carnegie, the Peabody – you know what I mean. The skeletons of ancient camels, horses, cats, sloths, and their beastly kin are often treated as osteological distractions by visitors who are swiftly moving in the direction of the dinosaurs. And this imbalance holds for news, too. A new horned dinosaur with an unusual arrangement of ornaments is catnip for click-hungry websites, but a fossil mammal with headgear that’s just as strange? You’ll barely hear a peep. And while this post won’t solve this gross imbalance in our attention, it’ll at least highlight a truly strange herbivore just as worthy of headlines as any dinosaur.

The herbivorous mammal, named Xenokeryx amidalae by Israel Sánchez and coauthors, roamed Spain around 16 million years ago. It didn’t look quite like anything alive today. The beast had elongated canine teeth – giving it a sabertoothed look like musk deer and muntjacs – but it also had fur-covered ossicones jutting from over each eye and from the back of its skull.

Xenokeryx wasn’t the only mammal to sport such a strange set of headgear. It belonged to a group called palaeomerycids that all had their own ornamental arrangements jutting from their skulls. For a long time paleontologists were divided on whether these creatures were more closely related to giraffes or to deer, but the new skull material from Xenokeryx, as well as a revision of other species, has allowed Sánchez and coauthors to settle the debate. The palaeomerycids were apparently the closest cousins to giraffes, the two lineages splitting from each other about 30 million years ago.

There aren’t any palaeomerycids left. The last of them went extinct about 4.9 million years ago. That’s undoubtedly part of what makes them so strange. If some of them had survived, they might not seem any more exotic than their living giraffe cousins. But we need to remember these oddities from the more recent stretches of the fossil record. They fill in the more recent chapters of the story that’s still unfolding all around us, showing just what evolution can do when released from the claws of the ruling reptiles.

Skull elements of Xenokeryx. From Sánchez et al., 2015.
Skull elements of Xenokeryx. From Sánchez et al., 2015.

Fossil Facts

Name: Xenokeryx amidalae

Meaning: Xenokeryx means “strange horn”, while amidalae is a reference to Padme Amidala from the Star Wars prequels for the resemblance between her hairstyles and the mammal’s ossicones.

Age: Around 16 million years old.

Where in the world?: Le Retama, Spain.

What sort of critter?: One of the palaeomerycids, extinct relatives of giraffes.

Size: About the size of a deer.

How much of the creature’s body is known?: Elements of the skull, jaws, limbs, and teeth.

Reference:

Sánchez, I., Cantalapiedra, J., Ríos, M., Quiralte, V., Morales, J. 2015. Systematics and evolution of the Miocene three-horned palaeomerycid ruminants (Mammalia, Cetartiodactyla). doi: 10.1371/journal.pone.0143034

[I also wrote about this beast for Nerdist.com]

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