Q36 - Triceratops Skull Injuries

Theoretical 2 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Some fossilised skulls of triceratops (a type of dinosaur) show injuries sustained while the animal was alive. The figure shows a drawing of a triceratops skull. Injuries in the highlighted bones were assessed across many fossils. The numbers give the number of individuals with injuries found in that bone, out of the total number of individuals in which that bone was analysed. The Squamosal bone is marked with an asterisk.

Two main causes of triceratops skull injuries are attacks by large predators (e.g. T. rex), or combat between adult male triceratops. Note that T. rex stood much taller than triceratops.

Triceratops skull diagram with injury frequencies: A=1/45, B=10/58, C=7/39, D=0/47

True or False?

Q36.1. Nasal bones are the most abundant of fossilised triceratops skull bones.

Q36.2. Triceratops collars were formed as outgrowths of parietal bones (which form the roof of the skull).

Q36.3. The squamosal bone has the highest frequency of injuries compared to all the analysed bones.

Q36.4. The distribution of injuries is better explained by combats between triceratops males, rather than T. rex attacks.

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Question reproduced from IBO 2023, Theoretical Paper 2, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF