An article published in the journal “Scientific Reports” describes a new species of lizard now extinct that lived in present-day Wyoming, in the USA, about 52 million years ago, in the Eocene period. Simon Scarpetta, a paleontology student at the University of Texas (UT) at Austin, named it Kopidosaurus perplexus because the various analyzes carried out on the available fossil skull give different results regarding its classification. The relationships also vary considerably depending on the type of analysis conducted, underlining the difficulties and uncertainties that may exist in both paleontology and biology field.