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Top 10 Open Access Fossil taxa of 2017: Zuul crurivastator

There is no Net Neutrality, only Zuul.” – Ajit Pai, December 2017.

Tied in 4/5th place with nothing less than the world’s oldest fossil mushroom comes Zuul crurivastator, first named and described by by Victoria M. Arbour and David C. Evans in Royal Society Open Science after the villain in the 1984 blockbuster hit, Ghostbusters.

Zuul hit the headlines in 2017 with every possible Ghostbusters-related pun possible. The fossil, despite not being located in a refrigerator, was exceptionally well-preserved for something so old.

The half-metre long skull is a beautiful sight to behold, despite being entombed in rock for around 75 million years. It also has much of its tail preserved, coming in at almost 3 metres in length. This size makes it one of the biggest ankylosaurs currently known.

Zuul, nicknamed ‘Sherman’ by the original gatekeepers, Theropoda Expeditions, was actually found back in 2014, during dinosaur hunting season, and completely by accident. A loading truck, while excavating a specimen of the giant theropod Gorgosaurus accidentally bumped into an errant ankylosaurian tail club. The specimen went to the Royal Ontario Museum (Toronto, Canada) in 2016, where researchers promptly began to fire lasers at it.

It manifested into the modern world, revealing itself to subcreatures Arbour and Evans, who began the process of digitising and describing the specimen. Generally you don’t see this kind of preservation in a major dinosaur group.

Artist rendering of Z. crurivastator. (Credit: Danielle Dufault, Royal Ontario Museum)

Zuul factfile:

  • What: Ankylosaurinae (Ornithischia).
  • Where: Hill County, Montana.
  • Diet: Plants (and souls).
  • Length: 6 metres (20 feet).
  • Weight: 2.5 tonnes (5,500 pounds).
  • When: Campanian (Late Cretaceous), Judith River Formation, Coal Ridge Member (76.2-75.2 million years old).
  • Defining features: Fricking awesome.
  • Scientific value: First known ankylosaurine with a complete skull and tail club. Also preserves osteoderms, skin remains, and keratinous sheathes on the body!

Paleontologists Victoria Arbour and David Evans working tailsde of the Zuul specimen. (Credit: Brian Boyle, Royal Ontario Museum)

The weighty club of aknylosaurs is usually thought of as a defensive weapon, being swung at predators who dared to get too close. I ain’t afraid of no T. rex. The club is surprisingly rare to find intact with the rest of the body in ankylosaurs, which makes Zuul a great opportunity to explore this use in more detail. The bony coverings that transformed ankylosaurs into a tank are also beautifully arranged in place, allowing researchers to know exactly what Zuul looked like in real life.


Arbour VM, Evans DC. 2017 A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation. R. Soc. open sci. 4: 161086.

Featured image: Danielle Dufault, ROM.

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