Size comparisons

[DinoFan83]

To display an interesting case of what seems to be convergent evolution, I put together some size comparisons. Here are the preserved/extrapolated skull and forelimb elements of an equivalently sized Megalosaurus and Yutyrannus, specimens BMNH 36585 and ZCDM V5001 respectively. Note that both specimens would be about 447 kg in life.

*This image is copyright of its original author

*This image is copyright of its original author

We can see that both of these animals display a number of similar features which suggests they may have had similar lifestyles. Both have quite large heads for their size (80 and 85.2 cm) that would have been quite wide and robust, and both display rather large and strong forearms for their size as well (humerus lengths 34.1 and 35.6 cm respectively), tipped with long, sharp claws, proportionally similar to many carnivorans that rely largely on their forearms for prey capture.

Another potentially interesting feature is the fact that both Megalosaurus and Yutyrannus are markedly different from their more famous relatives, the giant spinosaurids and tyrannosaurids, with their combinations of large arms and massive, robust skulls. Like Yutyrannus, tyrannosaurids would have retained a massive, strong skull, but would have had short, useless forearms. Likewise, spinosaurids shared large and powerful clawed forearms with Megalosaurus, but did not have a robust and massive skull as it did, instead having skulls much more similar to modern fish-eating crocodilians.

I think that from these comparisons, it can be concluded that both of these species would have had multiple very efficient to attack prey (mauling it with their deadly bites while simultaneously controlling and clawing it with their large clawed forearms), that because both evolved these to be very similar proportionally their hunting strategy must have been rather similar in some way, and interestingly, they both differ from relatives in similar ways due to the possession of these features. Reply