The first ocean and the largest ever, the Pre-ancient Pangeael Ocean was the home of billions of living things.  The Itchysaurs are one of he largest reptiles in the ocean.  However the Megaladonshark is the largest and can eat almost anything existent of its time.  Small whales such as the Pigmy Sperm Whale had already begun to evolve, which is not that much of a problem for the Megaladon as it is the size of a sperm whale.  The Pangeael Ocean was actually a very rough ocean to live in with storms that raged for weeks, the animals living in it had too evolve to much larger sizes. The Pangeael Ocean was begging to be split up because of the fact that during the Permian period, the sun was so hot it burned out lakes and rivers to nothing-ness.  Only once a year would the rains come and this wasn’t enough to stop the ocean from drying and splitting up.  Fortunately in the Mid-Jurassic there was a rain that lasted for days which caused the ocean to rise and a great flood to occur.  However after the flood, the oceans were not the same; there were now 3 oceans which were called The Three First Oceans.  The 3 oceans were the Tethys, The Boreal and still, because of its massive size, the Pangeael Ocean.  Today’s Pacific Ocean is actually only 1/4 of the size of the SMALLER Pangeael Ocean.