Patagotitan was a massive plant-eating dinosaur that lived in what is now Argentina during the early Cretaceous Period, about 101 million years ago. It was gigantic, measuring about one hundred twenty two feet long from snout to tail! The genus name, Patagotitan, translates to "Patagonia titan" in reference to where it was from in Argentina, Patagonia, and the fact that it was freaking huge...because "titan" means big. The species name, mayorum, is in honor of the Mayo family, the people who owned the land on which this dinosaur was found and excavated.
|My watercolor painting of a sick Patagotitan in the place where its bones, and the bones of its kin before it (also pictured) will be dug up by humans 101 million years later.|
Patagotitan is an amazing dinosaur. First of all, it was gigantic, definitely one of the largest land animals (let alone dinosaurs) to ever live. It was a member of the group of sauropod dinosaurs called Titanosauria. Titanosaurs were sauropods, that unlike many other kinds of long-necked, large-bodied dinosaurs, like the diplodocids or brachiosaurids, survived into the very end of the Mesozoic. On top of that, the very largest dinosaurs that we currently know, all happen to be titanosaurs, Patagotitan being near the top of even that list. Even more specific, all of these largest titanosaurs, including Patagotitan, also happen to have lived in what is now Argentina! Something about that part of the world during the Cretaceous favored extremely large body size in these dinosaurs. That something is still very much a mystery to paleontologists. The knee-jerk reaction to answer this question would be that these dinosaurs evolved so large as a defense against predators. However, even the largest known meat-eating dinosaurs would stop becoming a threat to a healthy sauropod once it reached a certain size, like say.... seventy feet, like Brontosaurus, or a whopping eighty-five feet, like Giraffatitan. But Patagotitan was one hundred twenty two feet long! Seems like overkill, but growing to that size would have taken a lot of nutrients and energy. Natural selection doesn't cause such extreme cases like this to just pop up randomly. There were reasons. We just haven't discovered them yet!
In order to be so large, Patagotitan had some special features about it that prevented it from simply collapsing under its own bulk when alive. First of all, its bones, despite being so large (the thigh bone is the size of a couch) were hollow inside with lots of air pockets. This did two things for the animal. First, it allowed it to be lighter, therefore raising the ceiling of how large it could become without being too heavy to move. (Birds have the same feature in their bones for lightness too, but they used it to fly, instead of gaining size. In fact, since birds are also dinosaurs, it is most likely that having hollow bones was originally an ancestral trait for dinosaurs.) Second, these air chambers were connected in life to its respiratory system, so when the animal was breathing, it was easier for the oxygen to get to where it needed to go throughout its vast body. Patagotitan's hips were particularly wide, and its legs were also pretty widespread. This was to help spread out its weight as much as possible when it was standing or walking. Being that large would have been taxing on an animal, so almost every part of its physiology had to take part in making sure it could support itself.
|The arm and shoulder blade of Patagotitan on display at the American Museum of Natural History in New York. These are some of the actual bones and have since gone back home, to Argentina.|
Another awesome thing about Patagotitan is that it is actually known from several specimens, six to be exact, not just one, which is what we usually get when we find a gigantic dinosaur. Between these six individuals, paleontologists were able to put together a pretty accurate skeleton of this dinosaur, only leaving about thirty percent of the skeleton still a mystery. Sadly, the skull was one of these missing parts, but skulls of sauropods rarely preserve because they are very delicate, compared to the rest of the body. Another detail is that by looking at the geology of the dig site in which they were found, paleontologists found out that these six Patagotitans all died years apart from one another. So something about that specific area was attracting dying Patagotitans. Perhaps it was near a river, that dried up from time to time and thirsty dinosaurs would come there looking for water during the dry season and died? It's a mystery.
|Patagotitan's butt. Note how wide set the back legs are to support its weight in life.|
So what's up with that size? Was Patagotitan the largest dinosaur ever? Well, that's a little complicated. The paleontologists who discovered this dinosaur initially thought so. They measured the height of one of Patagotitan's back vertebra and compared that number to a back vertebra of the dinosaur that was at that time thought to be largest, called Argentinasaurus. Patagotitan turned out to have a taller vertebra, mostly because of a taller neural arch (the crest-like piece of bone that sticks out of the top of the vertebra. If you run your finger down the center of your back, you can feel your own neural arches.) Going on those numbers alone, which is all that was really released to the public at the time, it would appear that Patagotitan was the largest of the two. But there's more to this story, than vertebra, however.
It turns out that despite having a taller vertebra than Argentinasaurus, many of the other bones of Patagontitan's bones that could be matched and compared to Argentinasaurus' were the less massive of the two. So While the Patagotitan may have been taller in some areas, Argentinasaurus appears to have been more massive. So it depends on what your definition of size really means. It's like comparing a giraffe to an elephant. The giraffe is certainly taller, but the elephant is definitely more massive. In addition to this, keep in mind that Argentinasaurus is only known from a few bones, and it is very difficult to get an idea of exactly how long its entire body was. So it is possible that Argentinasaurus was entirely larger in any sense of the word, than Patagotitan.
Another thing about size to keep in mind is that none of the Patagotitan specimens were fully grown when they died. At the same time it is possible that the fossils we have of Argentinasaurus may not have been from the largest individual of its species either...oh the debate goes on! See what I mean when I say it's complicated?
THAT BEING SAID...At the end of the day it is important to step back and look at this for what it is. Patagotitan was a really cool, almost completely known dinosaur that was gigantic! Worrying too much about if it may have been a little larger than the other known gigantic dinosaurs, as if it were some kind of contest, is pointless when there are way more exciting things to take away with the discovery and now publication of Patagotitan!
That is all for this week! What do you think about Patagotitan? Feel free to comment below or on the facebook page!
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José L. Carballido; Diego Pol; Alejandro Otero; Ignacio A. Cerda; Leonardo Salgado ; Alberto C. Garrido ; Jahandar Ramezani ; Néstor R. Cúneo ; Javier M. Krause (2017). "A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs". Proceedings of the Royal Society B: Biological Sciences. 284 (1860): 20171219. doi:10.1098/rspb.2017.1219.
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Ortiz, Edward, and Reuven Blau. “Meet Patagotitan Mayorum, the Biggest Beast in the City.” NY Daily News, 9 Aug. 2017, www.nydailynews.com/news/national/meet-patagotitan-mayorum-biggest-beast-city-article-1.3397477.