I think personally it was an Acrocanthasaurus an early creatacous dinosaur from North America there's an Acrocanthasaurus in A Jurassic Park Video game called Warpath which has a similar build and color pattern to the unknown sharptooth plus the arms are to long for a Carnotaur which had even stumpier forelegs than a t-rex, there are carnotaurs in Dinosaur although in Dinosaur they're too big. As for the sharptooth in season six I figured it was subspecies of t-rex or a different tyrannosaurid like albertosurus as the jaws are different than the green t-rexes in the movies.
