The average adult O. megalodon likely had a body shape similar to that of a typical Lamnidae shark, particularly the great white shark. While it is commonly assumed to have a body shape similar to the lemon shark, this is a reconstruction that ignores phylogeny.
This is not an established theory, but a hypothesis I speculated on, and I wanted to share it with you.
This estimate was made based on the assumption that Megalodon's body shape was similar to that of the great white shark. Although the body length has decreased, the mass is similar to recent estimates. The fact that Cretalamna, an ancestor of Otodus, resembled great white and mako sharks, and that Cretoxyrina, which occupied the same ecological niche as Otodus rather than Lamnidae, had a form similar to that of the great white shark, increases the likelihood that Megalodon's form was similar to that of Lamnidae sharks.
Due to the limitations of the fossil record, which consists only of fragmentary teeth and vertebrae, the size of Megalodon has not yet been determined. There is still much controversy, and my writing is merely one opinion.
Otodus megalodon(male)
Otodus chubutensis
Carcharodon carcharias(Deep blue)
Otodus chubutensis is a close relative of Megalodon, and while its teeth are very similar, they have serrated edges on the sides. The largest individuals reached 13.2 meters long, resembling small adult Megalodon size. (average body length is 9m.) The official fossil record spans from the Late Oligocene to the Middle(Late?) Miocene, but according to many fossil collectors, its existence is confirmed to be as early as the Pliocene.
O. chubutensis and Megalodon coexisted for a very long time and are frequently found in the same regions. Due to morphological similarities and simultaneous occurrence, experts have difficulty distinguishing between the two.
It is an undeniable fact that the actual range of Livyatan's holotype specimen exceeds 14 meters and approaches 15 meters, according to the opinions of various researchers and artists. However, it remains unknown whether it actually reached 17.5 meters, as suggested in the 2010 study. Since the paper was published, many people have accepted 15m(49ft) as the established standard, and I do as well. Currently, even if the holotype is estimated to be the largest, it does not exceed 17m(55ft). Nevertheless, the fact remains that it is the largest fossil sperm whale, comparable in size to the average size of extant male sperm whales, even if its dimensions have been reduced.