Thirty tons of weight, a length of 14 meters and a gigantic jaw with triangular teeth of 20 cm: we are speaking of the greatest raider of the seas, lived up to around 1,5 million years ago.. 

Its name is Carcharodon megalodon, an extinct shark characterized by great teeth (megalodon) thick, triangular, serrated in both the sides, with a length from 15 to 20 cm, 

Of this animal only the teeth and vertebrae have remained, being its skeleton cartilaginous, as that of all the condroittis, and therefore degradable in brief period of time. 

Analyzing the fossils teeth, the dimensions have been established, reaching the conclusion that probably the length of this shark would be of 13-14 ms with a weight of 20-30 tons. 

The study of the rings of growth of the rare recovered vertebrae points out that this animal lived for 35-40 years.
The megalodon shark, because of its dimensions, had to ingest since 600 to 1200 kg of food a day and its preferred preys probably were the prehistoric misticetis, whales from 3 to 6 meters of length and from 9 up to 18 tons of weight.

The presence of the Carcharodon megalodon has been inserted among the Miocene and the Pliocene (between 15 and 1,5 million years ago) and  the motive for the extinction is not certain: the two most accredited hypotheses are those of the lowering of the temperature of the oceans and a diminution of its natural preys.
The two situations could have happened also together also, smaller temperatures of the waters would have brought the shark preys, to new migratory routs decreasing the availability of food of 75%.

Some researchers affirm that the shark survived up to 10.000 years ago. In fact fossils teeth have been found whose analysis of the time, through the manganese accumulation, would bring to the aforesaid results. Some confrontations to these results concern the possibility that the manganese is crusted in following times to the fossilization.. 

Numerous criptozoologis affirm even that this shark is not extinct, but present in deep waters and therefore very difficult to observe..
The writer Steve Alten, in hisbook "MEG", imagines this panorama: a sample of Carcharodon megalodon, survived up to our days to abysmal depth, succeeds in arriving in surface (overcoming the tied up problems to the depth and pressure..) creating the terror among the humans.
Lately, in recent times there have been sightings of enormous creatures, similar to sharks, and the story of S.Alten seemed to have become reality but the animals probably described were calmer and harmless basking sharks .. (Cetorhinus maximus, nourishes him of plankton and overcomes the length of 10 m) 

The great similarity in the morphology of the teeth suggests that the Carcharodon megalodon is a "narrow relative" of the white shark (Carcharodon carcharias), but also here some researchers have considered the idea of the convergent evolution, that is two evolutionary lines that have brought to similar results, inserting therefore the  Carcharodon megalodon in a different genus.
The new scientific nomenclature, for these researchers, would be therefore Carcharocles megalodon.

(recostruction of Carcharodon megalodon jaw)

Tooth of Carcharodon/Carcharocles megalodon,
thick, triangular, serrated in both the sides.

Marco Angelozzi - www.prionace.it

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