The longest known theropod skull

[Vladimír Socha]

Good day!

I was wondering, what is currently the longest known theropod skull on record? There are many contradicting data and it seems like Giganotosaurus carolinii type specimen had a skull that would be about 163 cm long, while Spinosaurus aegyptiacus (largest specimen) would have a skull some 160 to 169 cm long. There is also rumour about 180 cm long Mapusaurus roseae skull and of course the second specimen of Giganotosaurus (dentary, about 6.5 % larger than the holotype). Thank you in advance! VS.

References:

Calvo, J. O.; Coria, R. A. (1998). New specimen of Giganotosaurus carolinii (Coria & Salgado, 1995), supports it as the largest theropod ever found. Gaia. 15: 117–122.

Henderson, D. M. (2023). Growth constraints set an upper limit to theropod dinosaur body size. The Science of Nature. 110 (1): 4.

Hendrickx, C.; Mateus, O.; Buffetaut, E. (2016). Morphofunctional analysis of the quadrate of Spinosauridae (Dinosauria: Theropoda) and the presence of Spinosaurus and a second spinosaurine taxon in the Cenomanian of North Africa. PLOS ONE. 11 (1): e0144695.

Therrien, F.; Henderson, D. M. (2007). My theropod is bigger than yours...or not: estimating body size from skull length in theropods. Journal of Vertebrate Paleontology. 27 (1): 108–115.

[Tristan Stock]

I know the Giganotosaurus skull reconstruction has been criticized by various authors. Your Dinosaurs Are Wrong did an excellent summary of that various reconstructions in their Giganotosaurus video, but tldr the older models that makes the skull very long seem to be due to reconstructing the hindskull like that of an abelisaur with an angled quadrate, rather than the straight quadrate we know carcharodontosaur skulls have. Angling it backward makes the whole rest of the skull artificially longer, which produces the very high length estimates. In reality it’s probably closer to 1.5 meters or lower, although detailed figures of all the skull material would be appreciated to sort this out.

Milan specimen of Spinosaurus is probably from the longest published theropod skull, but it is just a snout with everything past the nares missing. We know a lot about spinosaur skulls so the length is probably close to accurate, but if you want something we have the a much better skull from, Sue is still very much a contender, even if their head is squashed. Tyrannosaurus certainly has the most massive skull of any known theropod, even if it’s not as long.

As for Mapusaurus, as with most things in academia I’d refrain from rumors until something is published.

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[Thomas Richard Holtz]

Another issue here is that you have to be specific as to what measurement you use for "skull length". Is it the tip of the snout to the back of the occipital condyle, or the tip of the snout to the posteriormost point of the quadrate? Both are legitimate uses of the term "skull length", but these two numbers will be different for the same skull. So you need to verify with your sources which method was used for which skulls.

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[Chaos Soahc]

So any claims of theropod skulls exceeding 1.5 meters other than spinosaurus is false? 

[Thomas Richard Holtz]

Not necessarily false. Two issues:

1) Are the substantiated by measurements in the primary literature, taken by people who have measured the specimens and not just looked at restored pictures of them?

2) Which measurement for "length" was used?

If either of these two points are unclear, you shouldn't regard the claims as more than rumors. Possibly true, but not substantiated.

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