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Paleozoic and Mesozoic Seas

Paleozoic Diorama More Diorama

from the Dinosaur Collector update 121110

at the end of the Permian there was a major change in the worlds oceans.  The last of the trilobites had  become extinct, brachiopods are now a found primarily in extreme environments like cold water and caves.  Reef building stops and the corals from from the Paleozoic become extinct.  By the Middle Triassic the dominate Paleozoic Seas fauna were either extinct or only existed as a few species.  The modern sea fauna largely evolves replacing the community of stationary filter feeders characteristic of the Paleozoic to one dominated by active swimmers.  Diaspid reptiles have often returned to sea, the latest being the Marine Iguana.  Their side to side walking motion on land converts easily an efficient fish like motion for life in the water.   The Mesozoic starts in the Triassic and ends with Cretaceous.  Not everything big and dead is a dinosaur.

Mesozoic Seas

Dino Boyz

Dino Boyz Sam and Taliesin with the Under Sea action set.

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Sea Life Diorama

Prehistoric Marine figures have never been common.  The MARX company produced a Kronosaurus that was copied by MPC and other toy companies.  The figure was pretty inaccurate even for the 60's.  The SRG metal figures that were sold in Museum gift shops produce a Mosasaur and a Dunkleosteus figure.  Some small headed long necked plesiosaurs and nothosaurs were also produced by minor toy makers.  The Starlux, Invicta , Schleich, Bullyland, CollectA, Kinto and Safari companies included prehistoric sea creatures in their lines.  In the last few years Procon, Kaiyodo Dino Tales and Yowies series have produced an explosion no only in number of figures but in the species represented.  The Walking with Dinosaurs Documentary made the pliosaur Liopleurodon a house hold name and a popular figure.

The Triassic Seas were initially populated by the survivors of the Permian extinction, the first ichthyosaurs, Grippia and  Utatsusaurus are found in the Early Triassic.  Placodonts and nothosaurs appear in the fossil record in the Early Triassic.  By the Middle Triassic reefs were once more being built, Tanystropheus is established as an aquatic predator and the new  seas fauna began to take on a modern character .  The Nothosaurs relatives the Plesiosaurs develop in the Late Triassic.                        


In the Early Jurassic, Pangaea breaks up and the sea expands  to cover many Triassic Deserts. The flowering of the ichthyosaurs and plesiosaurs.


The Late Jurassic Seas see two major groups of plesiosaurs.  The long necked small headed plesiosaurs ate smaller sea creatures.   The pliosaurs get really big the size of modern whales.  Modern fish (telosts), sharks and ammonites populate the sea.  Several members of the crocodile family go to sea and the first family of turtles goes to sea.

Early Cretaceous seas are dominated by the famous pliosaur Kronosaurus . Giant squids and ammonites are common. modern Sharks and boney fish are evolving into new types. Ichthyosaurs are decline suddenly and there may have been changes in the ocean circulation that made the depths oxgen deprived. The long necked Jurassic plesiosaurs die out and are replaced by elasomsaurs thought to be descended from pliosaurs. The early mosasaurs appear.


In the Late Cretaceous Seas new reptiles take to the seas. Shallow seas spread over many of the continents.  Some birds will give up flight to become dedicated swimmers.  The mosasaurs relatives of today's monitor lizards go to sea as do some crocodiles.   They get big and mosasaurs give birth to snakes who may be the only descendants of the great Mesozoic aquatic diaspids to leave descendants. Turtles made it out of the Mesozoic also but they are classed as anaspid reptiles.      



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