Why is defining the absolute maximum size of Livyatan melvillei inherently statistical rather than definitive?

Because a complete postcranial skeleton has never been recovered, requiring extrapolation.

The primary obstacle to stating a definitive maximum size for Livyatan melvillei is the incompleteness of its fossil record. Paleontologists have only found limited remains, most notably a partial skull and several teeth; a complete postcranial skeleton, which would provide direct length and mass measurements, has never been unearthed. Consequently, scientists must rely on comparative scaling methods using living relatives like the modern sperm whale, or extinct relatives like Zygophyseter. Because the resulting body length estimates can range significantly—from 13.5 meters to 17.5 meters depending on the ratio used—the final conclusion about its absolute maximum size remains inherently statistical and dependent on which anatomical ratio proves most accurate for this ancient lineage.