Name Meaning: Titanic Lizard
Geologic Era: Cretaceous
Location Discovered: Neuquen Provence, Argentina
Range: Worldwide (even Antarctica)
Size: Up to 30+ meters in length
Extinction Date: 65 million years ago (K-T extinction)
Titanosaurs can be said to be the successors to the sauropods of the Jurassic period. In several cases, they exceeded the sauropods in size. The largest known land animals ever found are titanosaurs, with a few species probably exceeding 100 feet in length. Our eggshell pieces come from one of the smaller titanosaurs, at about 40-50 feet in length. The species was not explicitly stated, but I was able to narrow down the possibilities using the little information I was given.
Based on the stated size of the animal, the province found, and geologic era, I believe this shell fragment to have come from either Rinconsaurus or Muyelensaurus. Both of these animals are from the Neuquen Provence, and fit the size parameters given.
Both Rinconsaurus and Muyelensaurus were on the smaller side for titanosaurs, and had a more slender build than some of their larger cousins. Teeth found associated with Rinconsaurus remains are peg like, similar to those found on Diplodocus. This means that Rinconsaurus probably stripped vegetation and swallowed it whole.
Sauropods and titanosaurs did not have the teeth to grind or chew their food. They would have either have had to rely on bacteria in the gut to break down plant fiber, or just have to eat a lot to get the required nutrients. Rinconsaurus is known from three individuals (two adults and a juvenile), so the skeleton is fairly well understood. The only part that is really incomplete is the skull, though we can assume that it probably had a more elongated skull based on some of its close relatives.
Rinconsaurus and Muyelensaurus would have lived alongside some of the largest carnivorous dinosaurs of all time, including Giganotosaurus. They also lived with the unusual Carnotaurus, an abelisaurid theropod. Either of these animals could have been a threat to even an adult Rinconsaurus or Muyelensaurus. Dinosaur size, as far as can be discerned, reached its peak in South America in the mid-to-late Cretaceous.
After that point, dinosaurs began to shrink in size, though one could argue that sophistication and specialization increased as well. Tyrannosaurus, for example, may have been outclassed by Giganotosaurus in size, but Tyrannosaurus had a proportionately larger brain and stronger bite force. It does pose an interesting question to biologists…what might dinosaur life had looked like if it had been allowed to persist 20 million years longer than it did?
Skeleton: “Rapetosaurus” by Lisa Andres from Riverside, USA – Field Museum Mother & Child. Licensed under CC BY 2.0 via Commons – https://commons.wikimedia.org/wiki/File:Rapetosaurus.jpg#/media/File:Rapetosaurus.jpg
Life Restoration: “Rinconsaurus test 2” by I, Steveoc 86. Licensed under CC BY-SA 3.0 via Commons – https://commons.wikimedia.org/wiki/File:Rinconsaurus_test_2.jpg#/media/File:Rinconsaurus_test_2.jpg
onsaurus test 2″ by I, Steveoc 86. Licensed under CC BY-SA 3.0 via Commons – https://commons.wikimedia.org/wiki/File:Rinconsaurus_test_2.jpg#/media/File:Rinconsaurus_test_2.jpg