One of a very rare discovery! The discovery is considered to be one of the oldest-known tumors ever found in a fossil. The said beast is among with the many species that prowled Tanzania 255 million years ago as dated by scientists.

The tumor was not sought, the researchers of the University of Washington is studying unrelated aspect of the jaw when they found the benign tumor composed of miniature tooth-like structures embedded next to the root of the creature's enlarged canine tooth. University of Washington paleobiologist Megan Whitney said that before they cut open the jaw there was no indication that there was a tumor. "It was pure luck that we found the tumor", he added.

According to Mobile Reuters, the researchers identify the tumor as compound odontoma. A condition in which benign dental tumor grows within the gums or other soft jaw when people get one it require surgery in order to remove it.

The creature was a member of gorgonopsians (Gorgon face) an extinct suborder of therapsid sinapsids, it is at one time called mammal-like reptiles or stem mammals. They grow up to 3 meters long, though the said jawbone belongs to a smaller one.

These species lived during the Permian period, until they were wiped out by the largest mass extinction on Earth. What appeared to be remarkable with the tumor is that whether malignant or benign, it usually involves soft tissue so it could be rarely fossilized but this one includes hard enamel and dentin. Christian Sidor , paleobiologist of University of Washington said, "ancient tumors generally need to affect hard parts such as bones and teeth in order to be preserved in the fossil record."

Similar discoveries were also found before but tumors not in mammals, only in fish such as in a 300-million-year-old fish and a 350-million year-old armored fish but with some disputes, as Q102.7 reported.

The relevance of the study and this discovery is for deeper understanding of diseases. As Whitney said, "Fossils allow us to understand the evolution of diseases in deep time and have the potential to provide clues as to the causes of diseases that afflict humans."

The research appears in the Journal of the American Medical Association Oncology.