The Triassic  update 060303

Early Triassic

The Permian extinction killed of 90% of all land species.  This left a limited fauna for the Early Triassic with much lower diversity than in the Permian.  The Dicynodonts  especially Lystrosaurus are the most common members of every land based community and to a lesser extent the early Cynodont Thrinaxodon.  There was a major revival of the amphibious Labyrinthidonts.   

Lystrosaurus has been found on every continent including Antarctica.  It was an important part of proving the theory of continental drift.

Kaiyodo gives the Lystrosaurus from its Dino Tales line a sprawling reptilian look.

Lystrosaurus  was a sheep sized dicynodont that survived the Permian extinction and filled the empty habitats.  Originally seen as a aquatic animal like the modern hippo, it had no special adaptations for aquatic life.  Tasmanisaurus was an Australian version of Protersuchus.   

Lystrosaurus and Tasmanosaurus from Cadbury Yowies.

 The early archesosaur Euparkeria was a minor component of the Early Triassic fauna..  Diaspids had not been especially prominent in the preceding Permian.  The evolution of this group seems to have been inhibitated by the Pelycosaurs ( Dimitrodon and relatives) and their descendants. They seem to have filled filled specialized aquatic and flying niches waiting for their chance.   

 

(Scroll right ) Popular figure companies have largely ignored the Triassic.  The Starlux company from France is the exception.  Starting on the left is Euparkeria once thought to be a dinosaur ancestor.  Then there are the Labyrinthidonts and a Mastodonsaurus.  In the lower left a paper Thrinaxodon and upper right the aquatic paper Protersuchus note the hook at the end of the snout.

At the close of the Early Triassic or it may actuall be Middle Triassic, following the Lystrosaurus interlude, a new fauna characterized by the large carnivore Cynognathus and the large herbivore dicynodont Kannemeyeria. 

 

(Scroll right ) Cynognathus has a long  history  in dinosaur figure sets going back to the Marx playsets.  Above are two figures from the PlayVision mini dinosaur set.  The small green figure is the Mech version with two Panosh dicynodont figures.  The addition of tusks would make the figures more convincing.  Last is the Starlux  Cynognathus.  

In the Middle Triassic the rauschid archosaurs become the top predators. Cynodonts are the most common small to medium size carnivores.   Dicynodonts become specialized as large plant eaters.  The buck toothed rhynchosaurs and armored aetosaur's are the most common herbivores.  Prolacertiforms such as Tanystropheus were cousins to the archosaurs.  The long but inflexible neck was used to dart after fish.

 Late Triassic

The Late Triassic was a time of change.  Dinosaurs formed only a small part of the community initially.  There were two large extinctions in the Late Triassic one at the beginning and another at the end.  In the first the rhynchosaurs, dicynodonts and most cynodonts died out.  In the second the remaining cynodonts and thecodonts died out.  This left the dinosaurs, pterosaurs and crocodiles to fill the vacant niches.

Left the Starlux Protosuchus.  I used a Nabisco copy and a party favor figure to represent the armored Aetosaur's that where the common plant eaters.  Last is a large headed thecodont similar to Rauisuchus. 

The northern hemisphere communities are characterized by the abundance of phytosaurs and labyrinthidont amphibians.  The phytosaurs looked and probably behaved like crocodiles but evolved their features independently.  The distinguishing feature is that the phytosaurs nostrils are placed in front of the eyes instead of on the end of the snout.

This a Schleich gavial customized into a phytosaur by moving the nostrils just before the eyes.  The Mastodonsaurus is a hugh amphibian by Bullyland.

While the ornithisuchids and rauschids continued to share the top predator slot with dinosaurs, dinosaurs take over the small to medium carnivore roles and prosaurapods take over the herbivore category.  

Ornithosuchus the Thunder Beast from Sky Kids and the Play Vision Ceolophysis from their museum line.  Jurassic Park spawned an outstanding line of articulated figures produced by Hasbro.  The Ornithosuchus is the WalMart version and the two Ceolophysis are posable.

The rauschid Postosuchus was the biggest carnivore of its time and Plateosaurus was one of the largest herbivores of its time at 27 feet.  There were numerous similar  looking prosauropods  the 61/2-foot Anchisaurus , the 30-foot Euskelosaurus and the 13-foot Massospondylus.

The Postosuchus is from the new English Toyway line based on the Walking with Dinosaurs Documentary.  The Plateosaurus is from Jasman series of large vinyl figures.  

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