Monday, December 9, 2013

Siats: Prehistoric Animal of the Week

Allow me to apologize for the delay.  Yesterday I had been on a plane and when I arrived home I sat at my computer to complete this post...and fell asleep at the keyboard.  Normally I sleep on planes but that time I had not for some reason.  Again I apologize.

This week belongs to yet another recently discovered dinosaur!  Only described last month, check out Siats meekerorumSiats was a large, meat-eating dinosaur that lived in what is now Utah, USA, and lived during the middle Cretaceous period, about 98 million years ago.  The individual found would have been about thirty feet long from snout to tail.  Experts believe this specimen was only a juvenile, however, and that Siats could have pushed forty feet as a fully grown adult!  Its genus name is after a man-eating monster from the local Native American mythology, called a siats. 

How a living Siats meekerorum may have looked.  Illustration by Christopher DiPiazza.

Unfortunately the known remains of Siats are only fragmentary but enough bones were salvaged for experts to identify it as a member of the the allosauroid family.  It would have been closely related to dinosaurs such as Acrocanthosaurus, and to a lesser extent, Allosaurus and Saurophaganax.  These predatory dinosaurs typically had three fingers on each hand tipped with long hook-shaped claws.  They also had serrated blade-like teeth adapted for slicing chunks of meat off carcasses...or still living victims.

Some of the bones unearthed belonging to Siats.

Siats was an important find because of its allosauroid status.  All the known large predatory dinosaurs from later times in North America were Tyrannosauroids like Teratophoneus, Lythronax and eventually at the very end of the Cretaceous, Tyrannosaurus rex to name just a few.  All the large predators known before it, however, were other allosauroids.  Before the discovery of Siats, the middle Cretaceous of North America was sort of a mystery ecosystem which paleontologists had not found many fossils from at all.  Siats brings us one step closer to knowing what it was really like back then by telling us that allosauroids were going strong and were as big as ever at least until 98 million years ago. 

That's all for this week!  Join us next Sunday for another prehistoric animal of the week!  Hopefully it will be yet another newly discovered species!  (if I can paint it fast enough)  As always comment below or on our facebook page!


 Zanno, L. E.; Makovicky, P. J. (2013). "Neovenatorid theropods are apex predators in the Late Cretaceous of North America". Nature Communications 4. doi:10.1038/ncomms3827.

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