Final answer:
Purussaurus size was estimated using phylogenetic and non-phylogenetic approaches, with variations due to data weighting. Phylogenetic methods consider evolutionary history, unlike non-phylogenetic. The accepted size estimate is 7.6–9.2 meters.
Step-by-step explanation:
The size of Purussaurus, a prehistoric crocodilian, was estimated in the 2022 study using phylogenetic and non-phylogenetic approaches. Phylogenetic methods involve the use of an organism's evolutionary history to estimate its traits, while non-phylogenetic methods do not consider phylogenetic relationships.
The reason why phylogenetic and non-phylogenetic approaches yield different size estimates can be due to variation in dataset weighting. This means that the importance given to different traits or aspects of the specimens may affect the resulting size estimation. External factors such as environmental conditions or preservation state can also impact the estimations, though not explicitly mentioned here.
The currently accepted size estimate for Purussaurus based on recent studies is considered to be between 7.6–9.2 meters, although there may be variability with newer findings or refined measuring techniques.