A re-examination of a fossilized bone that had been lost in a drawer for decades has scientists amazed at the actual size of one to the most feared predators in prehistoric times, according to UPI.

The femur, from a dinosaur called an abelisaur, was recently re-examined by researchers at Imperial College London, and their calculations say the meat-eating predator weighed almost two metric tons, and stretched almost 30 feet in length, making it about the size of a double-decker bus.  The measurement estimations, if correct, will make this specimen one of the largest abelisaurs ever uncovered.

Abelisaurs lived in what is now northern Africa and fossil records have shown them living as far back as 170 million years ago, and as recently as 66 million years in the past.  The fearsome predators had tiny, pretty much useless forelimbs, but made up for the lack of arm strength with massive hindquarters and extremely potent sharp teeth.  Discoveries at other sites have suggested the abelisaur may have been an inland hunters, somewhat different from its cousins that preferred a fish diet.

Study co-author and researcher, Allesandro Chiarenza, said in a press release, that smaller fossils of the abelisaur had been found, but this recent discovery reveals how massive the flesh-eating predators had become.  Chiarenza adds the creatures may have looked a bit odd, since they were likely covered in feathers, with the tiny forelimbs, but they were unmistakably fearsome hunters and killers.

The fossil was originally discovered in an area of Morocco, known as Kem Kem Beds, that is famous for an abundance of dinosaur remains.  Scientists are somewhat confused about the number of bones discovered in the area, since they find it unlikely so many predators could co-exist in such a limited area.  Recent discoveries seem to suggest the area has been subjected to violent geologic conditions, and that may have jumbled up the fossil records and chronology of the finds.

Study co-author and researcher at the University of Bologna, Andrea Cau, said the study showed the importance of museums in the preservation of specimens of scientific value, and sometimes, the most unexpected surprises can be uncovered.