Giant Labyrinthodont Amphibian of the Late Permian Period. Known from Germany, hence the reference to the Rhine in its name. It was over 2 metres long.

It represents the plight of the older Amphibian linneages that had once run riot in the lush, humid and by far wetter Carboniferous Period. In the expanding deserts of the Pangaean Supercontinent, these once mighty Lower Vertebrates, were clearly outclassed by the tougher and more adaptable Reptiles that had even begun to supplant them by the end of the Carboniferous Period. Rhinesuchus is important, because is was once regarded as the very last of the older Labyrinthodonts. However, more recent finds show that not only did at least some relatives of the not so lucky Rhinesuchus survive into the Triassic Period - by enduring the full horror of the Permo-Triassic Mass Extinction Event - and do fairly well in this new Mesozoic Era, (until largely overthrown by Phytosaurs and Crocodiles) but indeed by some fluke of environmental and climatic isolation, one huge Labyrinthodont called Koolasuchus, survived until as recently as 100-90 million years ago at least. These then, are some of the most slippery characters in all of evolution.