December 13th

Box #13 in our count down is Rhomaleosaurus…

Days 1-5 of the count down.
Days 6-10 in the count down
Days 11-15 of the count down
Days 16-20 of the count down
Days 21-25 of the count down
Rhomaleosaurus, a giant, early pliosaur with a very keen sense of smell

Rhomaleosaurus: the “Strong Lizard”

Rhomaleosaurus was one of the earliest large marine reptiles to achieve the status of apex predator, and prowled the seas of early Jurassic England. First named in 1874, this prehistoric creature has a long and proud history, with the added benefit of having a complete skeleton and skull. Unfortunately, the original description was rather short, and it wasn’t until the skull was fully prepared in 2006 that the giant predator could finally be fully described and studied.

Rhomaleosaurus grew to about 23ft long (7m), and lived alongside a variety of plesiosaurs, smaller pliosaurs, crocodilians (including those specialized for lives at sea), fish, and pterosaurs. From the pristine preservation of its skull in glorious 3D, paleontologists can propose that it could hunt in the water by smell. Passages in its skull show it had sensory organs very much like sharks, which allowed the animal to pick up scents in the water.

Of course, hunting would only be one benefit, and one can look to modern animals for inspiration on other behaviors. In fact, many animals that have a keen sense of smell not only detect the scent itself, but also the “shape” of the smell. When an object moves through air or water, it emits its scent in a sort of cloud that trails and dissipates behind that object, like how the movement of a hand can form a shape of turbulence in smoke or mist.

The shape of the “scent cloud” can give an animal a lot of information about the size of the creature it is tracking and where it is going, may it be potential food or a mate. It is also very useful in finding one’s birth place to raise young (or abandon them in a nursey place). It is not so much the smell of the scent itself, but all the information the animal gets from the “shape” of the scent that is so valuable to the creature in every day life.

Even though extinct and modern animals are very different from each other, we can still learn a lot about possible behavior by discovering what is similar. In this case, the organs that detect scent in the water and what all animals with a keen sense of smell have in common.

4 thoughts on “December 13th

  1. Rhomaleosaurus is now more intriguing thanks to this. I had no idea that it would take such a long time for proper description but Quetzalcoatlus has faced a similar fate. Maybe it was different for both, but you get what I mean.
    For today, my critter of focus will be Isotelus, a trilobite from the Ordovician of the Northwestern United States and Canada. This trilobite was first named in 1824, and the species I. rex (not to be confused with the Indominus Rex from Jurassic World) is currently the largest trilobite ever found as a complete specimen. Additionally, the species Isotelus maximus is the state fossil of Ohio.


    1. Yes, it’s unfortunate how many fossils get set aside. There are so many things that people want to accomplish, and so many things that can somehow delay or make certain tasks almost impossible.

      At some point I need to make a whole series of trilobite stickers. Like Ammonites, Trilobites can also use a little more attention. 🙂


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