I think some reports have pointed to some kind of living Elasmotherium but the long reptilian tale really doesn't add up. Plus natives would surley think of that as a large Rhino and not a completely different creature.
From my research Emela-ntouka AKA Chipekwe is a large horned reptile known to kill Elephants but I'm not sure about eating them. For my cryptid stories I have gone with the theory that it is an animal that has evolved from the Ceratopsia Dinosaurs.
Most of the time they are described as two different names for the same creature like Big Foot & Sasquatch. At least on all I've read or seen. I am interested in the creature you described, it's also easy to get confused with Ngoubou and a few other dinosaur-esk creatures said to be living in Africa. The science is based on speculation so I can't argue. I should point out however that these a designs for a fictional series of stories I'm working on and I have already taken some liberties e.g I crossed the Loveland Frog and Lizard man, I've made the death worm much bigger and given Nessie legs.