Found in Montana, the skeleton is the most complete ankylosaur unearthed to date
DANIELLE DUFAULT/© ROYAL ONTARIO MUSEUM
Zuul is back. But don’t bother calling the Ghostbusters. Zuul crurivastator is a dino, not a demon. A 75-million-year-old skeleton unearthed in Montana in 2014 reveals a tanklike dinosaur with a spiked club tail and a face that probably looked a lot like its cinematic namesake.
The find is the most complete fossil of an ankylosaur, a type of armored dinosaur, found in North America, researchers report May 10 in Royal Society Open Science. It includes a complete skull and tail club, plus some preserved soft tissue, says study co-author Victoria Arbour, a paleobiologist at the Royal Ontario Museum in Toronto. “It really gives us a good idea of what these animals looked like.”
The bones reveal that Z. crurivastator had spikes running all the way down its tail, not just on the club itself. That arrangement means the weaponry was more than just a “massive sledgehammer,” Arbour says. The club was a formidable weapon. The term crurivastator comes from the Latin for “shin destroyer.”
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Arbour previously created mathematical models to calculate the force with which similar ankylosaurs might have swung their tails. These appendages provided a winning combination: good at absorbing impacts and able to smack an opponent hard enough to hurt, she says. Despite their armor and fearsome tail, ankylosaurs were plant eaters. So they probably used their tails to smack predators or compete with other ankylosaurs.
Arbour and museum colleague David Evans plan to investigate the thin sheet of fingernail-like material covering the bony plates on the tail, along with other details of the fossil that are typically lost in such old specimens. The rare, preserved soft tissue might even let scientists extract ancient proteins, Arbour says, providing insight into how these building blocks of life have changed since the days of dinos.
Having all this material in hand, she says, “kind of pushes the envelope about what we can identify in the fossil record.”
UNSQUISHED SKULL Zuul’s skull got crushed a bit during fossilization. This 3-D reconstruction shows what the skull probably looked like when the dino was alive. Julia Hulme/© Royal Ontario Museum
V.M. Arbour and David C. Evans. A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation. Royal Society Open Science. Published online May 10, 2017. doi: 10.1098/rsos.161086.
S. Milius. A fly called Iyaiyai. Science News. Vol. 159, May 26, 2001, p. 330.