WWD: Allosaurus fragilis

The lion of the Jurassic. The most common large predator of the Morrison Formation, or well, in WWD, the ONLY large predator of the Morrison Formation (sorry Torvosaurus and Ceratosaurus). This species is known from dozens of fossils, several nearly complete, so this is one of the most well-known dinosaur species.

One issue that that has always plagued Allosaurus is estimates on its maximum size. Often, earlier size estimates often put it at twelve or even thirteen metres in length, which is the measurement used in WWD. However, the vast majority of adult Allosaurus fragilis fossils correspond to animals of between seven and nine metres in length, with 8.5 metres considered average, although there are very rare individuals of greater size. The largest probable A. fragilis, specimen AMNH 680, corresponds to an individual slightly over thirty feet long, which is the approximate size illustrated. I won't get into Saurophaganax/A. maximus for this, because it would be getting rather egregious in spectacle over realism choosing that over the far more common A. fragilis, especially when Diplodocus is already the bigger species. Either way, there's no evidence for any T. rex-sized Allosaurus ever being around.

I chose The Ballad of Big Al colouration design to help break up the monotony of greenish-yellow dinosaurs in the episode and also because it's objectively superior. This is not actually Big Al (MOR 693) though, since that's since been classified as a different species, A. jimmadseni, which lived chronologically earlier in the Morrison Formation. Also, a currently unpublished paper indicates Big Al was actually an ovulating female and died at 16 years old, rather than male and dying at six in the special. Weirdly, Al fell into the normal size range for a typical subadult Allosaurus, at only 7.5 metres long, but the program chose to depict him at a staggering ten metres in length and still growing at the time of death.

An oddity of the design for Allosaurus in the series is giving it a rather blunt skull, and with the horns over top the eyes rather than being in front, making it look almost Carnotaurus-like. The former can be explained by the design being primarily based on a badly damaged skull (USNM 4734) that was poorly restored, rendering it much shorter than a normal Allosaurus skull, and the latter was fixed for the redesign in The Ballad of Big Al. It also had the very, very strange decision to give them tympanum fenstrae, making them look frog-like, but I, and probably nobody else on Earth, thinks they're likely so I don't think anyone will be upset that I did not include them.