Giant Killer Fish of water kingdom

In yet another fascinating story of archeology, scientists have discovered a fossil of a fish, that could be the water version of the giant killer T-Rex. Dating back to 85 million years, this extraordinary fossil of a Prognathodon has a special fins on the tail that could propel the animal at astonishing speeds across the ocean. With a streamlined body like a shark, this giant killer fish grows upto 17 meters in length and could weigh up to 20 tons. Definitely, this should have been the ruler of the oceans during its times.


Being caught in the jaws of a Prognathodon meant almost certain death, although the lizards were still vulnerable to attack themselves, with one fossil bearing the marks of a shark bite in its spine.


The latest and best specimen was dug up from rocks in central Jordan, with part of its soft tissue preserved, including the perfect outlines of its tail fin and flippers. A member of the mosasaur family, the marine reptile discovered measured just five feet long and was a juvenile when it died. It would have ended up six times its size had it lived.


This led to the idea that they were slow swimmers but the new fossil described in Nature Communications has a crescent-shaped tail fin similar to whales and extinct marine reptiles called ichthyosaurs that resembled dolphins.


The latest and best specimen was dug up from rocks in central Jordan, with part of its soft tissue preserved, including the perfect outlines of its tail fin and flippers, which indicates the lizard was a highly efficient swimmer


Dr Johan Lindgren, of Lund University in Sweden, said they were similar swimmers to sharks, ‘a finding that significantly expands our understanding of the level of aquatic adaptation achieved by these seagoing lizards.’ He described the skeleton, which is complete save for the head and part of the tail, as ‘extraordinary’.


Dr Lindgren said: ‘The bones are generally in a pristine condition and retain their original three-dimensional shape, although some skeletal elements were fractured or lost during the excavation of the fossil; the latter are now represented by natural moulds.


‘In addition, plant rootlets have penetrated and partially dissolved a string of vertebrae near the end of the tail.


‘The exposed elements of the pectoral girdle and rib cage are somewhat disturbed and the latter structure has suffered slight crushing; otherwise, the skeleton is in nearly perfect articulation, preserving, for example, a virtually complete, hydrofoil-like forelimb surrounded by skin impressions.’


The terrifying creatures could grow up to 17 metres long, weigh as much as 20 tonnes and would have spent most of the day swimming near the seabed stalking their next meal from the cover of seaweed and rocks


Mosasaurs breathed air, were powerful swimmers and were so well adapted to living in the warm, shallow seas prevalent during the Late Cretaceous period that they gave birth to live young, rather than return to the shore to lay eggs.


Dr Lindgren said: ‘The findings in the present study on Prognathodon, along with recent previous work on the streamlined body shape, keeled scales and modified limbs provide compelling evidence derived mosasaurs were hydrodynamically advanced animals capable of high efficiency swimming.


‘Moreover, the emerging evidence suggests aquatic adaptations evolved relatively quickly within the group, that is, within less than 10 million years.’

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