The Rachitrema dinosaur is very unknown. To be honest, the Rachitrema may not even be a dinosaur. Even though a major fraction of paleotologists claim that it is a dinosaur there are some who say that it was a ichthyosaur (ancient marine mammal).
The Rachitrama was described in 1982 by Sauvage and is very inconclusive. The fossil findings were so mimimal to the point that this dinosaur/reptile/mammal could not be classified yet. There were some parts that resembed the ichthyosaur and others that more resembed the an ancient reptile.