Jurassic Waves chapter 2: Big Predator

Period: Late Jurassic (Late Tithonian)

Date: 145,000,000 BC

Location: Central and southern Laurasian islands





That something far, far bigger than Cryptoclidus, Ophthalmosaurus or Metriorhynchus hunts in these waters is obvious from the occasional partial skeleton on the seabed: here and there a complete tail, without a single bone from the rest of the body; elsewhere a head and forelimbs, with no trace of the tail. These are the remains of Animals as much as 20 feet long that have been quite literally bitten in half.
Only a few times in its history has Earth witnessed a predator anything like the size of the culprit. Large male Liopleurodon can reach 33 or more feet long, and there are even close relatives of it, other Pliosaurs, that touch 43-49 feet long – specifically in the larger Pliosaurus. This is almost double the length of the largest land predators of all time. In the sea, though, Animals can grow to be a whole lot bigger and there are one or two other marine Vertebrate predators in the same size range as Liopleurodon. In the distant future of the Quaternary, Sperm Whales will reach 52-67 feet long; and back in the Triassic some Ichthyosaurs knocked on 69-75 feet – specifically in Shastasaurus. But while Sperm Whales and Shastasaurus will prey/preyed on things like Cephalopods, Liopleurodon and its kin are equipped to kill other Animals much larger than themselves (as well as smaller prey).
The head of Liopleurodon alone is 4.1-5.1 feet long and home to a fearsome collection of dagger-like teeth, the longest of which are at the tip of the snout. Eyes on top of its head show that Liopleurodon attacks from below, while its chest shows an Animal engineered for explosive ambush. A reinforced ribcage harbors colossal muscle structures deigned to pull the flippers down in immensely powerful strokes as it launches itself unseen from the depths.
As with any marine hunter, catching prey is not the whole problem – a predator also has got be able to remove chunks of flesh, something that is far harder to do in water than on land. Hypercarnivorous Sharks have solved this problem by having such incredibly sharp teeth that the bite is normally sufficient to remove each mouthful, while Pseudosuchians that are capable of swimming spin in the water to tear off bits of meat. Liopleurodon, and its fellow Pliosaurs, meanwhile has one of the thickest necks, allowing it to thrash tis head from side to side and rip its prey apart.
Reptiles, as a rule, cannot smell underwater – when such kinds as Pseudosuchians or Testudinatans dive, they close off their nostrils completely to prevent water getting in. But Liopleurodon, along with all the Plesiosaurs, has an arrangement that is utterly different and is the key to its success as a hunter. Its sensory system allows Liopleurodon to detect minute amounts of chemicals in the water – traces of blood, excrement, a prey viviparous Animal giving birth – but, most crucially of all, it can tell where these smells are coming from. Liopleurodon smells in the same way that the future Humans will hear: the brain figures out where a sound is coming form through the difference in the sound reaching the right and left ears. For Liopleurodon, it is the smallest difference in the smell reaching its left nostril and its right that signal a scent’s origin and allows it to sniff out its prey before it runs any risk of being seen.

To Be Continued