It's arguably one of the most famous sequences in an already famous movie. Trapped on a mysterious island, the beautiful actress Ann Darrow (played by Fay Wray) is menaced by a gigantic predatory dinosaur. Her only hope of survival comes in the form of King Kong, the massive titular ape that battles the carnivore in a brutal fight to the death that ends with the ruler of Skull Island dispatching the tyrant via breaking its jaw.

Time and again, this battle has been homaged and parodied by many knock offs and media throughout the years. The image of a gorilla battling a dinosaur may as well be ingrained in pop culture, all the way up to 2021 with the release of Godzilla vs. Kong.

Throughout it all, a single burning question remains:

Just what the heck is this guy?

While general consensus and history has described it as a Tyrannosaurus, there's another popular theory that it might actually be an Allosaurus due to the three fingers instead of the more traditional two associated with T. rex.

Now obviously when discussing stuff like this it's good to look at the words of the creators...except even the creators are divided on what it is. According to King Kong: The History of a Movie Icon from Fay Wray to Peter Jackson by Ray Morton, director Merian C. Cooper referred to it as an Allosaurus. By contrast, stop motion animators Willis O'Brien and Marcel Delgado describe it as a Tyrannosaurus. The script itself doesn't help since it only refers to as a Meat-Eater, a title which was adopted on its page by Wikizilla.

Feel free to take a look at the script with this link if you're interested:

In short, we've got conflicting ideas one what it is, and it's up to the viewer to decide. Personally, I do think it's possible to come up with a definitive answer when you consider the general perception of theropod dinosaurs at the time as well as the real inspiration that went into what we'll refer to as the Carnosaur for now.

These days when you look at a depiction of a Tyrannosaurus and Allosaurus side by side, you can tell them apart. Back then though when dinosaurs were still new and were still being properly classified, it was believed that the two species were closely related. This is reflected in contemporary depictions, where the two were depicted as looking a lot like one another.

As seen above in a pair of beautiful paintings done by the legendary Charles R. Knight, both look very similar to one another. There are some key differences of course, particularly with the slimmer build of the Allosaurus and the stubbier arms of the Tyrannosaurus, but to an untrained eye they do look very similar to each other. So, the confusion between the two can be understandable.

What helps us was that these paintings helped inspire Willis O'Brien with his depiction of both species in The Lost World (1925). While the Allosaurus was the primary big carnivore, a Tyrannosaurus DID make an appearance hunting and killing an Agathaumas (a ceratopsid that's now considered a dubious genus).

Again, we can see the difference here. The Allosaurus is a bit slimmer and has longer arms. While admittedly I couldn't find a clearer image of the Tyrannosaurus model, we do see that it is a bit bigger and has much shorter arms.

If we compare these two images side by side, we can see that the Carnosaur from King Kong resembles the Tyrannosaurus from The Lost World. Both have a bulkier build than the Allosaurus, and both have shorter arms. Admittedly they are being depicted with three fingers which has led to some confusion, but this is also easily explained since T. rex was believed to have three fingers at the time. The very first mounted skeleton of a Tyrannosaurus Rex at the American Musuem of Natural History (AMNH 5027), featured the three fingers.

This particular specimen in my mind helps cinch the view that the Carnosaur is in fact a Tyrannosaurus. According to Ray Morton again, this display at the American Museum of Natural History, this was the display that served as a model for the animal seen in King Kong. All the evidence, from a look at the models to how predatory dinosaurs were depicted during the time all points to the animal being a T. rex.

That being said, the confusion between the two species is understandable. They weren't depicted as being as distinct as they are nowadays. But it is important to remember how dinosaurs were depicted back then by the scientific community to better understand how they were depicted in movies and popular culture released at the same time.

A big thanks to Wikizilla for providing a bit of a roadmap for this post.