Question concerning Brachiosaurus and Ultrasaurus

[klausman@rz.uni-sb.de (Klaus Richter)]

I'm recently reading the book "Dinosaur Rediscovered" by Don Lessem -
once again, it's a quite book .
There he tells about Jim Jensen and his Ultrasaurus, and their is a
picture painted by John Sibbick the most of youi probably know - it
shows Ultrasaurus, Supersaurus and Gillettes Seismosaurus.
Ultrasaurus looks like a huge Brachiosaurus.
And if I take a look to the leg reconstructed by Jensen, it looks like
a huge leg of Brachiosaurus, there's almost no difference between Jensen's
leg and the leg of the Berlin Brachiosaurus.
For me - I'm not a palaeontologist, maybe there are differences between
both dinosaurs - these animals should have one name - Ultrasaurus or
Brachiosaurus. What's the actual discussion about it (if there's one)?

Klaus Richter
Universitaet des Saarlandes
Geb. 16, Zi. 2.35
Tel: 0681-302-4614
Saarbruecken