Complex sentence: Generalized weight, based on some studies have historically found extremely low weight estimates for "Quetzalcoatlus", as low as for a individual, a majority of estimates published since the 2000s have been higher, around.
Split into simpler sentences: Generalized weight, based on some studies that have historically found extremely low weight estimates for "Quetzalcoatlus", was as low as for a individual. A majority of estimates published since the 2000s have been higher, around.