True scale of megalodon shark revealed

[Still Waters 50,948]

The enormous size of a prehistoric mega-shark made famous in Hollywood films has been revealed for the first time in its entirety by a UK study.

Previously only the length of the Otodus megalodon had been estimated, but a team from the University of Bristol and Swansea University has determined the size of the rest of its body, including fins as large as an adult human.

The great white shark – depicted in the 1975 movie hit Jaws – is a distant descendant of the megalodon and often measures more than 6 metres in length.

Researchers used mathematical methods and comparisons with living relatives to find the overall size of the megalodon, which lived from about 23m to 3m years ago but has attracted fame more recently in Hollywood movies including The Meg.

https://www.theguardian.com/environment/2020/sep/03/researchers-reveal-true-scale-of-megalodon-shark-for-first-time

Quote

Body dimensions of the extinct giant shark Otodus megalodon: a 2D reconstruction

https://www.nature.com/articles/s41598-020-71387-y

 

[Jon the frog 2,267]

The teeth similarities push in the white shark appearance. But with only the teeth, it's hard to imagine the beast fully. Maybe it didn't have a dorsal fin...maybe it was a flattened ambush predator ? Would be great to find better specimen than a couple of vertebrates and some teeth.

[Carnoferox 6,260]

1 hour ago, Jon the frog said:

The teeth similarities push in the white shark appearance. But with only the teeth, it's hard to imagine the beast fully. Maybe it didn't have a dorsal fin...maybe it was a flattened ambush predator ? Would be great to find better specimen than a couple of vertebrates and some teeth.

There is actually a preserved vertebral column from Belgium with ~150 associated vertebrae which has been studied by the same team.

https://www.palass.org/sites/default/files/media/progressive_palaeontology/2020/posters/poster_2020_175.pdf

All lamniform sharks have the same number of fins, so it's pretty certain that megalodon would've had 2 dorsals, 2 pectorals, 2 pelvics, 1 anal, and 1 caudal like the rest of them. We also know that it would've had an active, predatory lifestyle like a great white so would've had a similar body plan. The only sharks that are flattened ambush predators are orectolobiforms like wobbegongs and squatiniforms like angel sharks.

Edited September 3, 2020 by Carnoferox

[Jon the frog 2,267]

1 hour ago, Carnoferox said:

The only sharks that are flattened ambush predators are orectolobiforms like wobbegongs and squatiniforms like angel sharks.

Yep, but they are species we know of... maybe strange form of lamniform existed before. It's just that the Megalodon image that we have sell well. Does the very partial clue that we have can make us jump to an easy conclusion ? We don't have a lot of shark remains because of their cartilaginous skeleton.

We asume that megalodon is a lamniforme because of

1) teeth :some talk about convergent evolution

2) coprolite that are assumed to be from them and are looking like lamniform ones... 

Still Its genus placement is not in cement, right now some phylogenists talk about putting them in the family Otodontidae who have no living members or either Carcharocles, Megaselachus, Otodus, or Procarcharodon....consensus not done yet.

https://www.floridamuseum.ufl.edu/science/preserved-shark-fossil-adds-evidence-to-great-whites-origins/

We have seen dinosaur fossil turning into something quite differrent when more complete skeleton are found. We can take the Spinosaur for exemple. The tall long legged Spinosaur was a good looking apex predator dinosaur with a long snoot, quite a favorite for a lot of people. Now it's a lot more more a punk crocodile and look a bit funny.

Edited September 3, 2020 by Jon the frog

[Carnoferox 6,260]

2 hours ago, Jon the frog said:

Yep, but they are species we know of... maybe strange form of lamniform existed before. It's just that the Megalodon image that we have sell well. Does the very partial clue that we have can make us jump to an easy conclusion ? We don't have a lot of shark remains because of their cartilaginous skeleton.

We asume that megalodon is a lamniforme because of

1) teeth :some talk about convergent evolution

2) coprolite that are assumed to be from them and are looking like lamniform ones... 

Still Its genus placement is not in cement, right now some phylogenists talk about putting them in the family Otodontidae who have no living members or either Carcharocles, Megaselachus, Otodus, or Procarcharodon....consensus not done yet.

The tooth formula and morphology confirm that megalodon is a lamniform without doubt. The convergent evolution of the dentition is in relation to great whites, not to lamniforms as a whole. The vertebrae also confirm this, as they have the characteristic radial lamellae of lamniforms. The coprolites are irrelevant as there's nothing other than size indicating they're from megalodon; most sharks have a spiral valve intestine so the shape alone is not indicative.

The tooth morphology of megalodon and bite marks on prey bones reveal that it preyed on marine mammals like small whales and seals. The round vertebrae suggest a fusiform body shape, unlike the more compressed vertebrae of flattened sharks. The dermal denticles ("scales") also suggest a streamlined body suited for fast swimming. All the evidence points to a similar ecological niche to the great white, which would result in a similar (albeit larger and stockier) body plan.

It's now widely agreed that megalodon is an otodontid and not a lamnid like great whites, with the debate coming down to the use of the genera Otodus and Carcharocles (Procarcharodon and Megaselachus are rarely used). Essentially there are five species of megatooths currently considered valid, in this chronological order: obliquus, auriculatus, angustidens, chubutensis, and megalodon. Some argue that all five species should just be Otodus since they represent an anagenetic lineage, meaning the species directly evolved into one another. Others argue that the lack or presence of tooth serrations is sufficient enough to split them into two genera, with non-serrated species in Otodus (obliquus) and serrated species in Carcharocles (auriculatus, angustidens, chubutensis, and megalodon). Personally I think all five species should just be Otodus and that serrations are not significant enough to split. This is the taxonomy that the authors of this paper went with and it is quickly becoming the consensus, with seemingly less Carcharocles supporters every year.

Edited September 3, 2020 by Carnoferox

[Cookie Monster 8,030]

Great White sharks dont actually stop growing at any point in their life. We know the same applies to lobsters although I cannot find if it applies to squid as well. In European legends we have giant sea monsters. 

It raises the possibility that we dont find gigantic specimens because we have been fishing the waters heavily for the last 2 or 3 centuries. I`m not aware of them building up a genetic profile of the Great Whites so it might be that Megalodons are very old, very large, great white sharks who had the food available to reach such gigantic sizes.

[Carnoferox 6,260]

Just now, Cookie Monster said:

Great White sharks dont actually stop growing at any point in their life. We know the same applies to lobsters although I cannot find if it applies to squid as well. In European legends we have giant sea monsters. 

It raises the possibility that we dont find gigantic specimens because we have been fishing the waters heavily for the last 2 or 3 centuries. I`m not aware of them building up a genetic profile of the Great Whites so it might be that Megalodons are very old, very large, great white sharks who had the food available to reach such gigantic sizes.

Not likely in the slightest.

Although similar overall, the teeth of megalodon differ from great whites in several key characteristics like the formula, root shape, bourlette, serration density, etc. It is 100% certain that they are not the same species as great whites, and are not even in the same family.

It is true that great whites don't stop growing, but their growth slows significantly after they reach maturity. They do not live long enough to be able to reach megalodon sizes.

[NCC1701 82]

It died out just 2.6 million years ago, so our early ancestors were probably on their menu too.

[Carnoferox 6,260]

On 9/8/2020 at 4:12 PM, NCC1701 said:

It died out just 2.6 million years ago, so our early ancestors were probably on their menu too.

3.6 million years ago, and encounters between sharks and hominins would've been very rare.