The Tangasauridae is a family of eosuchians, which contains two representatives, Hovasaurus and Thadeosaurus.
Hovasaurus lived in Madagascar during the Late Permian. The most striking feature of this 50 cm long aquatic reptile was its tail. It was twice the length of the rest of the body and deep and flattened from side to side. each of the tail vertebrae was extended above and below the midline. The result was a tail that formed a broad, stiff paddle, allowing Hovasaurus to swim efficiently. Another unusual feature of Hovasaurus is the mass of pebbles found in the abdominal cavities of most of the specimens recovered. It is thought these reptiles swallowed stones as ballast, to help them sink quickly in the water when diving for fish prey, or to keep them submerged when feeding.
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Thadeosaurus also lived in the Late Permian, in what is now known as Madagascar. This lizardlike creature was about 60 cm long, of which 40 cm constituted its tail. The five clawed toes on each foot were greatly elongated, and so arranged that the longer toes were on the outside. This had the advantage of allowing most of the toes to remain in contact with the ground as the foot was lifted, and so give a strong push of the surface with each step taken. The sternum, or breast bone, was massively developed, to help increase the stride of the forelegs.
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Author: Koen Stein
Last updated: 21/11/2005
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