|Can Deinocheirus do kung fu? Or is Mongolia to far away?|
Deinocheirus is perhaps the embodiment of dinosaurian diversity itself. It shows a variety of different features, including:
- Hooked thumb claws (present in Spinosauridae)
- Duckbill (present in some of Hadrosauridae)
- A heavily enlarged mandible (present in Shantungosaurus)
- Elongated arms (present in Therizinosauria)
- A pygostyle (present in Oviraptorosauria and Aves)
- A dorsal sail/ridge/hump (present in Spinosauridae, some of Carcharodontosauridae, and Ouranosaurus)
- Shortened legs (present in Majungasaurinae, Metriacanthosauridae, Spinosaurinae, and Therizinosauridae)
- Strongly arched dorsal series (present in Hadrosauridae)
So, more or less, it's basically a display case of Theropoda's weirdest and a few odd ornithopod features chucked in there. To truly appreciate how strange it is, it might be nice to show it with some other giant Asian theropods.
|Same image as before, but Deinocheirus now has a few friends (and enemies... get outta there, Tarbosaurus)!|
Let's go through them one-by-one:
Therizinosaurus: This guy rivals Deinocheirus in mass, but was definitely shorter (in length), although apparently taller. With its stubby tail and pot belly, Therizinosaurus was one of the most devoted non-avian herbivorous theropods. Therizinosaurus has immense arms that were about 3.5 meters long (a good meter longer than in Deinocheirus), and they were tipped with sword-like claws. The peculiar thing about these two browsers was that they were contemporaries, both sharing the Nemegt Formation. Perhaps the lack of Asian titanosaurs had something to do with theropods moving in?
Tarbosaurus: If Tyrannosaurus was king, then Tarbosaurus was emperor. The biggest specimens could exceed lengths of 10 meters, and it would have been a formidable beast. This giant theropod was also a resident of the Nemegt Formation, and probably was the main enemy of Deinocheirus (and Therizinosaurus, too). Tarbosaurus is interesting since it has a proportionately bigger head than Tyrannosaurus. It also had a close relative called Zhuchengtyrannus that lived in China. Deinocheirus seems to have been longer and heavier (although I might do a follow-up post on the validity of this statement).
Yangchuanosaurus: For whatever reason, Yangchuanosaurus is often overlooked in arguing over who was the biggest theropod. But this odd theropod was quite large, reaching lengths of 10-11 meters. It was from way back in the Jurassic, and one of the largest theropods of that time, too. It had somewhat shorter legs than other allosaurs, and a rounder head.
Gigantoraptor: This is yet another theropod that grew to giant sizes and assumed an herbivorous lifestyle. At 8 meters long, it was not very big compared to Deinocheirus, but considering that the next largest oviraptorosaur (Anzu) was not even half as long as Gigantoraptor, it was by no means small (unless we start talking about sauropods). The eggs of this giant were each half a meter long and were laid in nests 3 meters across! Unlike Deinocheirus and Therizinosaurus, Gigantoraptor retained long legs.
Ichthyovenator: This enigmatic beast from Laos is a spinosaurid. This critter had a peculiar bifuricated ridge/sail/hump on its back. Like other spinosaurs, Ichthyovenator would have spent its days around or in large bodies of water, hunting a variety of prey items, especially fish. While Deinocheirus was primarily herbivorous, it also ate fish (based on gut contents).
Gallimimus: This slender, cursorial omnivore was a giant among its fellow ornithomimids, at 6 meters long. Gallimimus had very long legs for a theropod, although they actually were on the short side for ornithomimids. It probably was not as fast as Ornithomimus or Struthiomimus, but it still was a dinosaurian speed demon. Ornithomimids are unusual, since they entirely lost their hallux (commonly referred to as a dewclaw). This is one of the many features that allies it with Deinocheirus, and, perhaps surprisingly, is the closest relative of Deinocheirus out of all the theropods in the second image.
Monolophosaurus: The earliest and most basal theropod in our little collection is Monolophosaurus. This five and a half meter long carnivore had an unusual crest on its head, composed of the ridges on its snout. This crest would have been used for display. Monolophosaurus is from the Middle Jurassic, and is one of many odd crested theropods, with the Asian Sinosaurus and the Antarctic Cryolophosaurus also having bony head crests.
Achillobator: This 5 meter animal was a dromaeosaurid, the family of dinosaurs that includes several of our favorite feathered non-avian friends, including Velocriaptor, Deinonychus, and Utahraptor. While not as big as Utahraptor, Achillobator was still huge for a dromaeosaur (although the South American Austroraptor surpassed them both in length). Achillobator seems to be a fairly typical dromaeosaurid, albeit a very large one.
|MPCD-100/127's willing to talk but /18 and /128 are still trying to figure out what that puny biped is. These size comparisons sure can look a little odd sometimes!|
So there you have it. There were several large theropods that roamed Asia in the Mesozoic Era, but Deinocheirus actually seems to be the biggest of the bunch. So what does this mean?
- Give Deinocheirus the honor of appearing in your mega-theropod size chart (which we're all doomed to make someday) ;)
- Even among the giants, theropods still displayed incredible diversity. Wings, tail fans, and herbivory clash with the stereotypical view of claws, teeth, and insatiable carnivory. But that isn't a bad thing. It shows that even among the tyrants and the carchars, it's hard to ignore how mindbogglingly successful dinosaurs were as a whole.
It's a real shame that these wonderful giants are eclipsed by the giant theropods from elsewhere. Rarely do we get to appreciate the levels of diversity achieved by Asian theropods.
- Paul, Gregory S. The Princeton Field Guide to Dinosaurs. 2nd ed. Princeton, NJ: Princeton UP, 2016. Print. ISBN 9780691167664
- Since WP:OR doesn't apply to the world of blogging, I've taken the liberty to really closely compare these creatures and draw some parallels.
Without these guys, I'd be helpless and this post would never exist. Special thanks to the work of all those skeletal drawers out there!
- Scott Hartman: Deinocheirus, Gallimimus, and Monolophosaurus.
- Jaime Headden: Therizinosaurus and Achillobator
- Franoys: Tarbosaurus
- Greg Paul: Gigantoraptor
- SpinoInWonderland: Yangchuanosaurus
(NOTE:The Ichthyovenator was taken from my old image here. If you're looking for a skeletal of this guy then this one by PaleoGeekSquared is rather good.)