Monday, July 16, 2018

Helveticosaurus: Beast of the Week

This week we will be checking out an unusual reptile with anatomy that continues to stump paleontologists.  Let's check out Helveticosaurus zollingeri!

Helveticosaurus was a marine reptile that lived during the Triassic period, about 242 million years ago, in what is now Switzerland.  From snout to tail it measured a little over six feet long.  To be honest, I cannot find where this creature got its name from since the paper describing it from 1955 doesn't seem to be available in English.  But doing a little research I was able to find a translation to "Hell Reptile" from Norwegian.  If anyone would like to correct me I would love to know the true meaning of this animal's name if what I came up with is off.

Life reconstruction of Helveticosaurus in watercolors by Christopher DiPiazza.

Helveticosaurus is known from an almost complete articulated skeleton.   Because of this we have know a lot about its anatomy.  However, its combination of features is so unusual that scientists are still unsure as to what Helveticosaurus was, beyond a kind of diapsid reptile.  Diapsids have two openings in their skulls beyond their nostrils and eye sockets.  It's a vast grouping of animals, so it doesn't really narrow down what Helveticosaurus was closest related to.

Helveticosaurus skeleton on display in the Paleontology Museum of Zurich, in Switzerland.

Helveticosaurus had a long tail that was flattened laterally.  This would have been ideal for swimming.   It probably used its tail, powered by large muscles at its base, as its main mode of propulsion in the water.  However, unlike a lot of other marine reptiles, Helveticosaurus also had proportionally long, and very powerful arms.  It may have used these arms, tipped with long fingers which may have been webbed in life, to help steer while swimming.  It has also been suggested that these arms could have been another source of propulsion.

Close up of Helveticosaurus' skull.  It was broken and crushed sometime in the 242 million years since the animal died, but you can clearly make out the extremely long teeth.

The skull of Helveticosaurus is also uniquely short, almost box-shaped and its teeth were long, curved, and pointed.  The longest teeth growing from the front of the snout.  This is an especially odd combination of adaptations since most marine animals with teeth like that possess long snouts to better capture swimming prey.  Most marine animals with short snouts, like Marine Iguanas, have small teeth, that when paired with the blunt snout, are ideal for clipping underwater plants and algae.  It has also been suggested that the short snout, which allows for more concentrated power when biting down, was an adaptation for eating shelled mollusks and crustaceans, like modern walruses do.  However, animals that eat that kind of prey have blunt, wide teeth, for crushing.  Helveticosaurus' long, narrow teeth look like they'd break if they were trying to crush hard shells.  Does this mean Helveticosaurus was an evolutionary failure?  Absolutely not.  It simply means we haven't figured out how it was feeding yet.  Hopefully a new discovery or idea will help us find out in the future!  As of now, most scientists agree that Helveticosaurus was eating meat in some form, based on its teeth.  Exactly which kind and how is still a mystery.

That is all for this week!  What do you think Helveticosaurus was using its odd combination of traits for?  Leave your ideas in the comments below!

Refereces

Bernhard Peyer (1955). "Die Triasfauna der Tessiner Kalkalpen. XVIII. Helveticosaurus zollingeri, n.g. n.sp.". Schweizerische Pal√§ontologische Abhandlungen72: 3–50.

Naish, D. (2008). "One of so many bizarre Triassic marine reptiles." Weblog entry. Tetrapod Zoology. 13 September 2008. Accessed 24 July 2009.

Neenan, J. M.; Klein, N.; Scheyer, T. M. (2013). "European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia". Nature Communications4: 1621

Friday, July 13, 2018

Dinosaurs at Nerd Nite Philadelphia

I had the privilege of being a speaker at Nerd Nite Philadelphia this week.  If you are not familiar, Nerd Nite is an organization that has people in a certain science, or other "nerdy" topic come into a bar and speak in front of an audience of other nerds about their field. 


I came in and talked about paleontology, different beasts that need more recognition, and particularly my experiences as a paleoartist and how depicting long extinct creatures certain ways can have positive, or sometimes detrimental, effects on how the public thinks about them. I also went into how it's a field that is always changing and that a hard-worked painting can become obsolete in a matter of seconds if a new, groundbreaking discovery is made.  (which is annoying, but ultimately still exciting.)


It was a lot of fun and I hope Nerd Nite decides to have me back soon.  Until then, here are a few snippets of video from the night.  


Sunday, July 8, 2018

Mastodon: Beast of the Week

This week we shall be checking out a popular prehistoric mammal that has integrated itself into much of our pop culture, from Power Rangers to Heavy Metal, and even played a role in American History.  Let's look at Mammut americanus, or as it's more commonly known as, the American Mastodon!  (I will from here on out be referring this animal as Mastodon, even though Mammut is the official genus, because Mammut includes many other species that will probably be covered in the future, and will therefore be less confusing.)

A female American Mastodon in the Pleistocene marshes of what is now New Jersey.  Watercolor reconstruction by Christopher DiPiazza.

Mastodon was a member of the group of mammals that includes modern elephants, called probiscidea, that lived in what is now North America, mostly the eastern coast of the United States, between 3 million and as recent as 11 thousand years ago, during the Pleistocene.  The largest specimens could grow to be over ten feet tall at the shoulder with sixteen-foot long tusks.  Average size, however, seems to hover a bit over seven feet tall at the shoulder.  Mastodon, like modern elephants, was sexually size dimorphic, with the males typically being larger than the females.  The males also tended to have longer, and more dramatically curved tusks than the females.  The original genus name, Mastodon, translates to "Breast Tooth" because of all the cool things you could name a totally awesome prehistoric beast, Georges Cuvier, French zoologist, and founding father of paleontology, apparently just really wanted to name something after boobs back in 1817.

I don't see the resemblance.

Mastodon earned its name because its back teeth were very different from the teeth of modern elephants, and even the teeth of Woolly Mammoths, both of which had teeth that had shallow winding ridges on their surfaces for grinding up soft plants.  Mastodon's teeth were more similar to molars, and possessed tall peaks on the tops of them, which were arranged in rows. (which apparently looked like breasts to enough people in the 1800s)  Mastodon teeth were better suited at processing a wider variety of plant material, including tough twigs and pine needles.  This makes sense because these kinds of plants were abundant in Mastodon's East coast forested habitat back in the Pleistocene.  Further, Mastodon's habitat would have experiences more dramatic seasonal changes, with different plants being present during different parts of the year, so Mastodon would have needed to have food sources all year.

American Mastodon skeleton on display at the Rutgers Geology Museum in New Brunswick, New Jersey.

Other than the teeth, Mastodon had a number of other characteristics that set it apart from its relatives.  Overall its body is longer and lower to the ground, with shorter, stocky legs.  It skull was more elongated, and less tall than other elephants, and it also possessed a prominent hump over its shoulders, where big muscles that helped to support the massive skull would have been attached.  Mastodon's tusks were longer than those of an modern elephant's, and curved slightly upwards and inwards.  These tusks were probably used for a variety of jobs, just like they are in modern elephants, but because they were so long and stretched out in front of the animal, they probably were better at moving trees and brush out of the way as the animal moved through the forest.  This ensured that the sensitive trunk and eyes were less likely to get poked by a branches and thorns. These tusks were also probably used for combat between Mastodons and also helped defend it from potential predators, which would have included humans.

Mastodon also would have had a coat of bushy fur covering most of its body.  This coat probably wasn't as thick as that of a Woolly Mammoth's, but it was certainly warm enough to keep Mastodon warm during the Coastal Winters.  

Mastodon is present in American history because Thomas Jefferson, one of the United States' founding fathers, was fascinated by them.  He collected Mastodon bones, along with the fossils of as many other prehistoric animals he could get his hands on, and studied them extensively.  In fact, when Lewis and Clark were about to embark on their journey into the previously uncharted (by Europeans) Western United States, Jefferson warned them to be on the lookout for possible living Mastodons, since he believed there was still a chance they could be alive in the wilderness somewhere.  Of course, they didn't find any living Mastodons, since they had indeed gone extinct thousands of years prior, but it's cool to consider that this prehistoric elephant used to be part of cryptozoology, like Sasquatch and the various lake monsters that some people continue to hunt for today. 
No longer a cryptid due to being extinct, but still a real animal!
That is all for this week!  As always feel free to comment below!

References

Agusti, Jordi & Mauricio Anton (2002). Mammoths, Sabretooths, and Hominids. New York: Columbia University Press. p. 106.

Fisher, D. C. (1996). "Extinction of Proboscideans in North America". In Shoshani, J.; Tassy, P. The Proboscidea: Evolution and Palaeoecology of Elephants and Their Relatives. Oxford, UK: Oxford University Press. pp. 296–315.

Giaimo, Cara. “Thomas Jefferson Built This Country On Mastodons.” Atlas Obscura, Atlas Obscura, 1 Sept. 2017, www.atlasobscura.com/articles/thomas-jefferson-built-this-country-on-mastodons.

Green, J. L.; DeSantis, L. R. G.; Smith, G. J. (2017). "Regional variation in the browsing diet of Pleistocene Mammut americanum (Mammalia, Proboscidea) as recorded by dental microwear textures". Palaeogeography, Palaeoclimatology, Palaeoecology. 487: 59–70. 

Larramendi, A. (2016). "Shoulder height, body mass and shape of proboscideans" (PDF). Acta Palaeontologica Polonica. 61.

Lepper, B. T.; Frolking, T. A.; Fisher, D. C.; Goldstein, G.; Sanger, J. E.; Wymer, D. A.; Ogden, J.G.; Hooge, P. E. (1991). "Intestinal Contents of a late Pleistocene Mastodont from Midcontinental North America". Quaternary Research. 36: 120–125.



Sunday, July 1, 2018

Gallimimus: Beast of the Week

Today let's check out a famous member of the ornithomimd family of dinosaurs.  Make way for Gallimimus bullatus!

Gallimimus was a theropod dinosaur that lived in what is now Mongolia during the late Cretaceous, about 70 million years ago.  Adults could grow to about twenty feet long from beak to tail.  The genus name translates to "chicken mimic" because the neck bones were particularly similar to those of modern chickens and other galliform birds, like pheasants and turkeys.  The species name is in reference to a bulla, a locket-like piece of jewelry worn by young boys in ancient Rome.  The back part of Gallimimus' skull reminded some scientists of the shape of these pieces of jewelry.  When alive, Gallimimus shared its environment with other dinosaurs, including Therizinosaurus, Tarbosaurus, and fellow ornithomimid, Deinocheirus

Life reconstruction of Gallimimus in watercolors by Christopher DiPiazza

Gallimimus was a member of the family of theropod dinosaurs, called ornithomimidae.  Ornithomimids all had long arms, long necks, and proportionally small heads.  Most of them also had long legs and a sleek build, suggesting they could run fast.  Struthiomimus, which lived what is now North America, is another famous member of this family.  (Deinocheirus, the largest known ornithomimid, was an exception to the sleek part of the description.)  Gallimimus was probably a very fast runner when it was alive, using its long powerful legs to take huge strides and its proportionally long tail to keep balance as it ran.  Like birds today, Gallimimus had hollow chambers in its bones, which would have been filled with air sacs in life.  These sort of adaptation allows the dinosaur to intake more oxygen into its body than it would if it was only relying on its lungs.  Gallimimus also probably had a one-way breathing system, where fresh air cycled through its body in one direction, instead of in and out like the respiratory systems of mammals.  Having a more efficient way to oxygenate the body means that Gallimimus could likely run faster for longer periods of time before it got tired.  Being able to outrun predators, like Tarbosaurus, was probably Gallimimus' primary defense.

Gallimimus is known from adult and baby individuals.  What is interesting is that the baby Gallimimus, have different skull shapes than the adults, with a much shorter snouts and proportionally larger eyes.  This is consistent with many baby animals today that are cared for by their parents.  Baby crocodilians and baby birds being the two best examples to compare here. 

Baby Gallimimus skeleton on display in Cosmo Caixa Science Museum in Barcelona. Photo credit Edward Sola.

As an adult, Gallimimus had a very long, toothless snout which was tipped with a beak.  The shape of Gallimimus' beak is more broad than those of many other ornithomimids, like Struthiomimus.  The underside of the beak possessed a series of thin tube-shaped structures, which some paleontologists suggest were adaptations for filter feeding water plants and small aquatic animals, since modern ducks and geese have similar structures in their beaks for feeding this way.  Other paleontologists think the structures in Gallimimus' beak were more adapted for cutting through tough vegetation on land, instead.  In addition to plants, Gallimimus, may very well have also eaten meat in some forms, like insects and other small animals it was able to snap up.  Gallimimus also had large eye sockets, suggesting it had good vision, which it probably used to help pick out food and look out for potential predators.

Adult Gallimimus skeleton on display at the Natural History Museum in London.  Photo credit" Drow male.

The arms of Gallimimus were proportionally long, but its fingers were short compared to the fingers of other known ornithomimids.  Its arms also don't show signs of being as strong as those of other ornithomimids either.  This means that unlike many of its relatives, which probably relied on their arms and hands for manipulating food more, Gallimimus may have relied on its beak and neck for foraging more. 

That is all for this week!  As always feel free to comment below!

References

Hurum, J. 2001. Lower jaw of Gallimimus bullatus. pp. 34–41. In: Mesozoic Vertebrate Life. Ed.s Tanke, D. H., Carpenter, K., Skrepnick, M. W. Indiana University Press.

Makovicky, P. J.; Kobayashi, Y.; Currie, P. J. (2004). "Ornithomimosauria". In Weishampel, D. B.; Dodson, P.; Osmolska, H. The Dinosauria (2 ed.). Berkeley: University of California Press. pp. 137–150.


Nicholls, E. L.; Russell, A. P. (1985). "Structure and function of the pectoral girdle and forelimb of Struthiomimus altus (Theropoda: Ornithomimidae)". Palaeontology. 28 (4): 64 –677.


Osmolska, H.; Roniewicz, E.; Barsbold, R. (1972). "A new dinosaur, Gallimimus bullatus n. gen., n. sp. (Ornithomimidae) from the Upper Cretaceous of Mongolia" (PDF). Palaeontologia Polonica. 27: 103–143.