Megalodon

[brandem]

Hey all, since wild safari seems to be releasing thier own C. megalodon figure next year inspired by great whites:

(wild safari Megalodon)

(Monterey Bay Great White)
and I recieved such a good reaction about my post suggesting Megalodon may have a body shape similair to that of sand tigers I thought I would share some of my past research into the body shape of Megalodon.

Carcharodon vs. Carcharocles
When first discovered Megalogon was attributed to the genera of carcharodon, which is fair, Megs had teeth very similair to great whites and predated on mammals very similair to great whites, because of this researchers and the public have long held the belief the Megalodon and Great Whites were closely related. However if we look at the teeth on more than just a macroscopic level we see that the serrations of the whites teeth are far larger and more irregular than Megs, and both have differing patterns of nerve and vein connections to name a few differences. In addition, some recenct discoveried have drawn the two apart:
Tracing the Ancestry of the Great White Shark, Carcharodon carcharias, Using Morphometric Analyses of Fossil Teeth
Kevin G. Nyberg, Charles N. Ciampaglio and Gregory A. Wray
Journal of Vertebrate Paleontology , Vol. 26, No. 4 (Dec. 11, 2006), pp. 806-814
Published by: Taylor & Francis, Ltd. on behalf of The Society of Vertebrate Paleontology
Article Stable URL: http://www.jstor.org/stable/4524633
this linking of great whites to the anchient broad toothed makos (isurus) pulls its' evolutionary lineage away from megalodon and leaves megalodon at the terminal end of the Carcharocles'(megatooth sharks) lineage with no living associated species in its genera,

Otodus to Megalodon
this would have us believe that Megalodon is more closely related to the ancient shark otodus than to great whites.  At first glance this seems unlikely, as otodus, though having large teeth, had several features that separate it from Megalodon i.e. two large cusplets and a very narrow uncerrated main tooth.  However a more complete fossil record has show possible transitional giant sharks between otodus and megalodon:

as we can see this suggests that from the Palaeocene to the Miocene evolution may have adapted Otodus' teeth to better exploit the whales that have moved from apex predators(basilosaurus) to mostly (excluding Livyatan melvillei) harmless filter feeders.

So Why A Sand Tiger's Body?
well if we accept that Megalodon is in the lineage of Otodus or at least within the same family(Otodontidae),  then maybe we can get an idea of what they look like by taking a look at what is proposed to be their progenator:Cretolamna

which kinda has the body shape of a Sand Tiger, and thats not really a suprise, within Lamniformes(the shared order of all the afore mentioned sharks) the Sand Tiger body pattern has appeared in at least four families (Mitsukurinidae, Pseudocarchariidae, Odontaspididae, Otodontidae), all of whom are different sizes and filling different niches, while the great white body form(with a tapering caudal peduncle supported by stout, lateral keels, with tiny second dorsal and anal fins, and a lunate caudal fin) has appeared in just one genus. 
So we are left with the decent possibility that Megalodon may have had a body shape reminiscent of Sand Tiger Sharks:


In Closing
Now im not trying to say Megalodon absolutely was not shaped like a great white (I was dead set on the idea as a kid), and im no Elasmobranchologist my degrees are in hominid evolution, and if anyone out there has more up to date research on Megalodon evolution please forward it to me I'm a junkie for the stuff, But also be sure to keep an open mind in science and don't let yourself get bogged down in dogmatic concepts.

Thanks all

[Balaur]

Hominid evolution? Thats awesome! Anyways, I do find your idea interesting. I actually like the idea of a it being shaped like that, but I don't know enough so I'll wait till there is more evidence.

[brandem]

Oh yeah more evidence is always good, if only we had a more intact vertebral column, there is so much left to learn about Megs and other ancient sharks, glad you're keeping an open mind too