Guess who’s back!!!!
After a reasonable hiatus of about 15 months, everyone’s favourite cryptid dinosaur Spinosaurus has returned to scientific literature. In a 79-page study, a research team lead by Nathan Myhrvold and Paul Sereno sought to dispel the long-running theory that Spinosaurus was capable of subaquatic behaviours in search of prey[i]. To do so, Myhrvold and Sereno examine and criticize a study published in 2022 from Fabbri et al. that concluded Spinosaurus was capable of diving based on the density of its bones.
In Fabbri et al. 2022, the bone density of Spinosaurus and two close relatives – the European Baryonyx and the older Suchomimus – were compared to modern animals capable of diving. They found that denser bones, which are observed in Baryonyx and Spinosaurus, were frequently found in diving animals and thus correlated to sub-aquatic foraging. Many thought this was sufficient evidence that Spinosaurus could dive, which I agreed with at the time. As you can guess by the existence of this article, my confidence – and that of the field – would not last.
According to Myhrvold and Sereno, the methodology used by Fabbri was flawed. Their study found inconsistencies in using bone density as an analogue for aquatic behaviours, as animals like elephants – famously not aquatic animals – have similarly dense bones to Spinosaurus[ii]. Overlap exists between bone densities of diving and non-diving animals, meaning it is a poor metric to assess how aquatic Spinosaurus was. Based on their results, the team concluded that the methodology used in Fabbri et al., known as a phylogenetic flexible discriminant analysis (pFDA), is difficult to use in paleontology and that no evidence exists to support Spinosaurus being a diver. If you are interested in reading for yourself, a link will be at the end of this article.
At this point, it seems that Spinosaurus was likely incapable of diving. Even if bone density was a reliable metric for diving capabilities, the biomechanical challenges of swimming with 2-meter-tall neural spines persist. Why would Spinosaurus retain structures that make submerging far more difficult by way of drag? Further, why would Spinosaurus evolve such structures while older genera like Suchomimus and Baryonyx were devoid of them?
It doesn’t seem to add up.
Given the history of Spinosaurus, I wouldn’t be surprised if the pro-diver camp – spearheaded by Nizar Ibrahim – publishes a new study sometime soon. Ibrahim did say that 2024 will be a big year for Spinosaurus. Mind you, he said the same thing in 2023 – and no paper was published. Time will tell to see if team dino-croc has more tricks up their sleeves, but for now, the ball is in the hands of team dino-stork.
I hope you enjoyed this article! If you want a more complete history of Spinosaurus, read “Why are Paleontologists Obsessed with Spinosaurus?”.
A link to Myhrvold and Sereno’s study can be found here: https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0298957&fbclid=IwAR0SvAMfag7xxAT213S6QImeoDqHr6_CggXXFWr-kvBPMzNdli03yW70bmQ#abstract0
I do not take credit for any images in this article, which come courtesy of the artists noted above.
Works Cited:
[i]Myhrvold, Nathan P., et al. “Diving Dinosaurs? Caveats on the Use of Bone Compactness and pFDA for Inferring Lifestyle.” PLOS ONE, edited by Jun Liu, vol. 19, no. 3, Public Library of Science (PLoS), Mar. 2024, p. e0298957. Crossref, https://doi.org/10.1371/journal.pone.0298957.
[ii] “Giant Dinosaur Was ‘Heron From Hell,’ Not a Deep Diver, Says New Analysis.” Biological Sciences Division | the University of Chicago, 6 Mar. 2024, biologicalsciences.uchicago.edu/news/spinosaurus-heron-hell-not-deep-diver.
“Giant Dinosaur Was ‘Heron From Hell,’ Not a Deep Diver, Says New Analysis.” Biological Sciences Division | the University of Chicago, 6 Mar. 2024, biologicalsciences.uchicago.edu/news/spinosaurus-heron-hell-not-deep-diver.
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