Sauroposeidon: Beast of the Week

 This week we will be checking out a huge dinosaur with an equally impressive name.  Enter Sauroposeidon proteles!

Sauroposeidon was a sauropod dinosaur (long neck) that lived in what is now Oklahoma, Texas, and Wyoming, USA, during the early Cretaceous period, about 113 million years ago.  Its genus name translates to "Lizard Earthquake God" after the Greek god, Poseidon, who in addition to his more famous association with the ocean, was also the god of earthquakes in Greek mythology. Since not a full skeleton is known, it is difficult to tell exactly how long this dinosaur could get (because necks and tails vary so much in sauropods) but estimates range anywhere between 89 to 112 feet (27-34 m) long, making it one of the largest land animals to ever exist. 

Watercolor of two Sauroposeidon squaring up by Christopher DiPiazza.

Sauroposaidon was originally known from only a few neck vertebra.  That being said these neck vertebra were enormous, the longest of any dinosaur found in fact.  Just one vertebra alone measured 4.6 feet (1.4m)! Later on more bones, including limbs, more vertebra, and even parts of the skull, which were originally referred to as their own genus, Paluxysaurus, were found to actually the same as Sauroposeidon.  Probably the most interesting bit of information regarding this dinosaur's discovery is the fact that some of its limb bones were initially misidentified as fossilized tree trunks!

Photograph of three neck vertebra from Sauroposeidon. (Photo credit: Mathew Wedel)

Sauroposeidon's neck bones were hollow, like those of a bird, and therefore extremely light for their immense size.  This would allow the dinosaur to more easily move its head and neck around without exhausting itself.  This was likely an adaptation for being able to reach leaves at the tops of trees to eat, but also could have been a way for the dinosaur to access a wide range of food without moving its body, thus conserving energy.  Large sauropods, like Sauroposeidon, likely needed to be eating most of the time they were awake in order to fuel their bodies. 

As an adult, Sauroposeidon likely had not predators to worry about.  As a juvenile, however, it may have been preyed on by Acrocanthosaurus, and as babies, it would have needed to watch out for Deinonychus.  It also coexisted with the tiny ceratopsian, Aquilops, and the long-tailed ornithopod, Tenontosaurus.

References

Rose, Peter J. (2007). "A new titanosauriform sauropod (Dinosauria: Saurischia) from the Early Cretaceous of central Texas and its phylogenetic relationships" (web pages). Palaeontologia Electronica. 10 (2). 

Wedel, Mathew J.; Cifelli, R.L.; Sanders, R.K. (March 2000). "Sauroposeidon proteles, a new sauropod from the Early Cretaceous of Oklahoma" (PDF). Journal of Vertebrate Paleontology. 20 (1): 109–114.

Wedel, Mathew J.; Cifelli, R. L.; Sanders, R.. K. (2000). "Osteology, paleobiology, and relationships of the sauropod dinosaur Sauroposeidon" (PDF). Acta Palaeontologica Polonica. 45: 343–388.

Leptoceratops: Beast of the Week

 Today we will be looking at the small ceratopsian dinosaur, Leptoceratops gracilis!

Leptoceratops was a plant-eating ceratopsian dinosaur that lived in what is now Alberta, Canada, during the late Cretaceous period, between 68 and 66 million years ago.  From beak to tail it measured about 6.5 feet (about 2m) and would have been able to walk on four or two limbs when alive. The genus name translates to "small horned face". 

Leptoceratops life reconstruction in watercolors by Christopher DiPiazza.

Leptoceratops was a ceratopsian dinosaur, which means it possessed a strong parrot-like beak and a bony frill on the back of its skull.  Unlike a lot of its larger relatives it didn't have any horns on the nose or over the eyes, but it did have large pointed jugal (cheek) bones which likely supported horns of some kind in life on the tips.  Its lower jaw was extremely deep, implying there were huge muscles there in life, giving it a powerful bite.  In the jaws it sported leaf-shaped teeth which were proportionally the largest of any ceratopsian.  The wear on Leptoceratops' teeth is unique, suggesting its jaws would  have moved back and forth in a circular motion, similar to many herbivorous mammals, but unheard of in any other dinosaur. This unique feeding style, combined with the raw power of its jaws and the sharpness of the beak, may have allowed it exploit a wider range of plant foods since it did not have the height advantage of other larger plant-eaters it coexisted with.  

Diagram of the tooth ware and chewing motion of Leptoceratops from the paper by Varriale et al. referenced below.

Leptoceratops had proportionally shorter but powerful arms, each armed with five strong fingers, the first three of which had claws.  Its hind legs were longer and it was likely capable switching between quadrupedal and bipedal walking and running depending on what suited it.  The vertebra in its tail had long neural arches, forming a tall almost fin-like profile, which may have been an adaptation for display against rivals of the same species or possibly predators, distorting the animal's profile and making it look larger than it really was.  

Two Leptoceratops skeletons on display at the Canadian Museum of Nature

A paper published in 2019 suggests Leptoceratops may have lived underground, thanks to multiple skeletons of different aged individuals found in what appeared to have been a collapsed burrow.  This doesn't seem impossible since Leptoceratop's extremely short frill wouldn't have gotten in the way if it was moving around through tunnels in life.  Sleeping underground is also a great strategy for avoiding predators.  

Despite its size Leptoceratops may have been able to fend off predators by simply being a jerk.  (This is not backed up by any fossil evidence but behavior rarely is.)

When alive Leptoceratops would have shared its habitat with some of the most famous dinosaurs, like Edmontosaurus, Ankylosaurus, Pachycephalosaurus, and Triceratops. It would have needed to watch out for predators like Acheroraptor, Nanotyrannus, and Tyrannosaurus, plus all the crocodilians and large pterosaurs, like Quetzalcoatlus, that were around. (although Quetzalcoatlus may have only been able to prey on babies.)  At first it's easy to imagine little Leptoceratops as nothing more than fodder for these predators since it had no horns or armor, but keep in mind that beak backed up with all that jaw pressure was potentially a devastating weapon.  It's not supported by any true evidence, but I always imagined Leptoceratops as extremely foul tempered and aggressive, even towards animals that dwarfed it, as a defense strategy. Modern Honey Badgers, Wolverines, and even members of the pig family effectively exhibit this strategy today. Even mighty T. rex couldn't have wanted to endure a bite on the toe from a Leptoceratops beak! 

References

Brown, B. (1914). "Leptoceratops, a new genus of Ceratopsia from the Edmonton Cretaceous of Alberta". Bulletin of the American Museum of Natural History. 33 (36): 567–580.

Fowler, D.W.; Wilson, J.P.; Freedman Fowler, E.A.; Horner, J.R. (2019). "The Horned Dinosaur Leptoceratops (Ornithischia: Neoceratopsia) Raised its Young in Communal Nesting Burrows: Evidence from Three New Bonebeds in the Hell Creek Formation (Maastrichtian, Late Cretaceous), Montana" (PDF). Presented Abstracts. Cretaceous and Beyond: Paleontology of the Western Interior. A Symposium Focusing on Cretaceous and Paleogene Vertebrate Paleontology of the Western Interior. 94. North Dakota Geological Survey. Miscellaneous Series: 20.

Maiorino, L.; Farke, A.A.; Kotsakis, T.; Raia, P.; Piras, P. (2018). "Who is the most stressed? Morphological disparity and mechanical behavior of the feeding apparatus of ceratopsian dinosaurs (Ornithischia, Marginocephalia)". Cretaceous Research.

Ryan, M.J.; Currie, P.J. (1998). "First report of protoceratopsians (Neoceratopsia) from the Late Cretaceous Judith River Group, Alberta, Canada". Canadian Journal of Earth Sciences. 35 (7): 820–826.

Varriale, F.J. (2016). "Dental microwear reveals mammal-like chewing in the neoceratopsian dinosaur Leptoceratops gracilis". PeerJ. 4 e2132.