The Spinosaurus – a plunge into the depths.

Being obsessed with dinosaurs as a child is a common occurrence, but as we grow older many people all but forget about these creatures, moving on to other interests. For this reason, most people probably have the same notion of what dinosaurs look like now than they did when they were 5 years old. The issue is that, whilst most dinosaurs themselves haven’t seen much action in at least 66 million years for reasons we are all familiar with, new archaeological discoveries mean that our ideas of what these beasts might have looked like are ever evolving.

One dinosaur that has suffered very notable changes recently is the Spinosaurus. In the last century, the accepted notion of what this dinosaur looked like has gone (in very rough terms, just to give you an idea) from T-rex with a spiky back to terrifying duck on steroids:

Classic perception (1900s):

Source: https://www.britannica.com/animal/Spinosaurus

Modern perception (2025):

Source: https://news.nationalgeographic.org/new-fossils-rewrite-the-story-of-dinosaur-evolution-and-ecology-and-change-the-appearance-of-spinosaurus/

Whilst the hardcore dinosaur fans aren’t too pleased with the Spinosaurus’ plunge into the depths, it is interesting, nonetheless, to investigate the role that physics had in shaping this new notion of one of the world’s most famous dinosaurs. But first, a bit of context:

In 2015, a team of investigators led by University of Detroit Mercy palaeontologist Dr. Nizar Ibrahim returned to the site where parts of a Spinosaurus skeleton had first been uncovered in 2008 (in the Kem Kem region of the Moroccan Sahara). In a previous study, the Spinosaurus had been identified as a fish-eating dinosaur with adaptations for an amphibious lifestyle. Suggestions that it may have been a truly water-dwelling dinosaur were met with opposition, however, because the partial skeleton provided little to no evidence of the propulsive structure needed to move such a giant dinosaur through water. Between 2015 and 2019, however, Ibrahim’s team recovered many more fossils of the skeleton, including a fin-like tail capable of extensive lateral movement and characterized by extremely long spines.

After preparing all the fossils, the team used photogrammetry to digitally capture the anatomy of the tail. Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena:

Source: https://www.factum-arte.com/pag/1345/PHOTOGRAMMETRY

To assess the performance of the tail a flexible model was produced and attached to a robotic system that mimicked swimming movements. They then compared the swimming performance of the model Spinosaurus tail to model tails from other animals, including crocodiles and other dinosaurs. The results were fully consistent with the idea of a truly water-dwelling, tail-propelled, “river monster”. “This dinosaur … probably spent most of its life in the water,” concluded Ibrahim.

This discovery points towards the possibility of an invasion of aquatic habitats by relatives of Spinosaurus. Discoveries such as these leave room for a world of further transformations of our notion of dinosaurs, so hold on to your childhood memories whilst you can…

Thanks for reading.

References:

Original news story: https://news.nationalgeographic.org/new-fossils-rewrite-the-story-of-dinosaur-evolution-and-ecology-and-change-the-appearance-of-spinosaurus/

Photogrammetry definition: https://lumenandforge.com/photogrammetry-history-and-modern-uses/