Big John is the greatest Triceratops known to date. On its huge collar, a keyhole has puzzled paleontologists. Bone analysis reveals what may have been one of the last major traumas endured by this giant.
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The Triceratops were they pugnacious fighters of the Cretaceous as shown by the countless illustrations in books dealing with paleontology? This question remains legitimate because the assumption that the Triceratops Upper Cretaceous (100.5 to 66 million years ago) were fighting among themselves is based in particular on the presence of their large bony collar decorated with three horns. The two supraorbital horns were the longest while the shortest was the nasal horn.
If the frill and the horns were, according to some paleontologistsallow individuals to identify themselves, they certainly protected the rear of the skull assaults from congeners. One of the indices of this defensive function is the presence of Windows abnormalities in the collarette of the Triceratops. These windows are actually holes, the shape and location of which suggest that they were caused by one or more traumas. However, in order to confirm that a concussion has indeed taken place, it is necessary to note that the bone has indeed attempted to repair itself after such an event.
A healing wound
Big John is the name given to the greatest fossil of Triceratops known. Its skull is about two meters long and two meters wide, and its supraorbital horns are over one meter long. the fossil was discovered in 2014 in the Hell Creek Formation in the United States which dates from the Late Cretaceous, and belongs to the species Triceratops horridus. During the reconstruction of Big John’s skeleton in 2021, a window was identified on his frill, at the level of the right squamosal bone. On closer examination of the structure, an Italian paleopathologist noticed that the edges of the hole were irregular and unusual. A bone sample was therefore taken from this area for research before Big John was sold at auction for over seven million dollars to a private individual. The results of the analysis of this sample are published in a study published in the journal Scientific Reports.
The microscopic analyzes reveal marks which may have resulted from a inflammation, as may occur after trauma in areas where skin and bone are very close together. The authors of the study also indicate that the bone tissue present around the window has been newly formed, that it is porous, covered with blood vessels and in the process of mineralization. The authors also highlight the presence of lacunar spaces similar to those observed when a human bone is remodeled.
The bone was in the process of repairing itself at the time of the death of the ceratopsid
They conclude that the window in Big John’s collarette is indeed the result of trauma and that the bone was in the process of repairing itself at the time of the ceratopsid’s death.
In addition, the wound measures approximately five centimeters at its widest point, has a keyhole shape and is located on the right of the collar. The authors therefore conclude that the injury was caused to Big John by one of his congeners whose supraorbital horn impaled the collarette from behind and tore the bone downwards, thus generating this particular form of injury. The authors estimate that Big John died six months after this event.
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