HELICOPRION:SHARK OR AMMONITE?                                                    Is Helicoprion a shark or an Ammonite? As humans we will ever know, all we can do is imagine. The reason I believe that the Helicoprion tooth spiral isn't a tooth spiral at al  is because. All prehistoric shark teeth have cracks in them from being used to kill their prey. But the fossilized teeth have no cracks in it what so ever. And if you were to take a Helicoprion tooth spiral and turn it on its side(see figure 1.1) it would be in the same shape as an Ammonite's shell. The shell would have sharp barbs all over the shell(see figure 1.2) if it really was a Ammonite shell. The barbs would make a great defense against Hybodus the reason(see figure 1.3) I believe Hybodus would be a predator on Ammonites is because it has teeth that look very similar to that of the Bull shark(see figure 1.4) and that is because the Bull shark's teeth are perfect for crushing shells. And to remind you this is only a theory.                         

Figure 1.1



Figure 1.2

Figure 1.4



Figure 1.3















                                       

MEGALODON                                                              

Megalodon  meaning "big tooth", from Greek μέγας (megas, "big") and ὀδον (Odon, from ὀδούς, odous, "tooth")) is an extinct species of shark that lived approximately 28 to 1.5 million years ago, during the Cenozoic Era (late Oligocene to early Pleistocene).
The taxonomic assignment of C. Megalodon has been debated for nearly a century, and is still under dispute. The two major interpretations are Carcharodon Megalodon (under family Lamnidae) or Carcharocles Megalodon (under family Otodontidae).Consequently, the scientific name of this species is commonly abbreviated C. Megalodon in the literature.
C. Megalodon is regarded as one of the largest and most powerful predators in vertebrate history, and likely had a profound impact on the structure of marine communities. Fossil remains suggest that this giant shark reached a maximum length of 14–18 meters (46–59 ft.),and also affirm that it had a cosmopolitan distribution.^[1] Scientists suggest that C. Megalodon looked like a stockier version of the great white shark, Carcharodon carcharias.                                                                                                Source:wikipedia