Sauropods were the largest dinosaurs on the planet. These long-necked quadrupeds have several very famous species in popular culture thanks to novels and movies like “Jurassic Park.” Brontosaurus, Brachiosaurus or some species of titanosaurs such as Patagotitan mayorum, the largest land animal in history, are some examples of sauropods that are well known among the general public. Precisely, among the sauropods is the family of titanosaurs, the largest known terrestrial vertebrates. And because of this spectacular feature, one of the most frequently asked questions about these dinosaurs is how did they get so big? We will need years of research to answer accurately, but the fossil of a small titanosaur has helped us understand the growth process of these giants.
More than ten years ago a fossil was discovered in Madagascar. The remains were forgotten because no specialist was able to identify exactly what species they had in front of them. Barely the size of a puppy, it was deposited in the warehouses of Stony Brook University in New York. There he remained waiting for some investigator to dare to solve his puzzle again. The occasion came in 2012, when paleontologist Kristina Curry Rogers rescued the mysterious fossil from oblivion . Rogers, from the Department of Biology and Geology at Macalester College in Minnesota, is an expert on titanosaurs and when she looked at the fossil, she saw a titanosaur skeleton but in miniature. It was then that they discovered that the fossil belonged to a hatchling of Rapetosaurus krausei .
The importance of the fossil is that, despite its young age, it has the same proportions as the skeletons of its adult relatives, only in mini size . Based on this evidence, the research team led by Kristina Rogers determined that the babies of these giant dinosaurs were born with the ability to walk and, possibly, feed themselves .
“This pattern differs from that seen in many contemporary dinosaur groups, such as theropods and ornithischians, for which evidence suggests parental care was important.”
Rapetosaurus krausei lived in present-day Madagascar during the Late Cretaceous, from about 70 million years ago, until the mass extinction that wiped out the dinosaurs about 66 million years ago. The fossil shows that the calf died when it was only a month or two old . Paleontologists estimate that he was born weighing about 3.4 kilos, but in the short time he lived he grew to 35 centimeters tall at the hip and about 40 kilos. This growth rate is shocking but logical, since if it had survived to adulthood, the Rapetosaurus calf could have reached 15 meters in length and weighed more than 10 tons .
Depending on the region and the chronology in which it lived, the calf’s death is attributed to starvation due to lack of resources after a devastating drought in its ecosystem. An idea that is reinforced by the thin cartilage that the fossil presents, a common symptom of animals that have gone hungry during their growth stage.
But this circumstance was caused by climatic factors, as far as the way of life of these dinosaurs is concerned, the researchers point out that these offspring had a high degree of self-sufficiency as soon as they were born . These precocious little ones did not need special care from their parents, as is usual in other species, and they are assumed to lead an active and independent life. So, according to these scientific premises, the adventures of Piecito in the movie “In Search of the Enchanted Valley” were not misguided.
The research team published the study on this fossil in the journal “Science” in April 2016. They pointed out that it is possible that other titanosaurs followed the same growth pattern with a skeleton of the same proportions as adults, but there is not enough evidence. to ensure that all giant long-necked dinosaurs were born as self-sufficient. Only the discovery of new fossils and continuous research will be able to clear up some of these doubts.
References:
De Jorge, J. 2016. The baby dinosaur, small but precocious . abc.es
Rogers, K. et al. 2016. Precocity in a tiny titanosaur from the Cretaceous of Madagascar . Science 352, 6284, 450-453. DOI: 10.1126/science.aaf150.
Rosen, M. 2016. Baby titanosaur was parents’ Mini-Me . sciencenews.org.
