H. antecessor remains are: In 1999 two ungulate teeth from TD6 were dated using uranium–thorium dating to 794 to 668 thousand years ago, and further constrained palaeomagnetically to before 780,000 years ago. In 2008 TE9 of the Sima del Elefante was constrained to 1.2–1.1 million years ago using palaeomagnetism and cosmogenic dating. In 2013 TD6 was dated to about 930 to 780 thousand years ago using palaeomagnetism, in addition to uranium–thorium and electron spin resonance dating (ESR) on more teeth. In 2018 ESR dating of the H. antecessor specimen ATD6-92 resulted in an age of 949 to 624 thousand years ago, further constrained palaeomagnetically to before 772,000 years ago. In 2022 ESR and single grain thermally transferred optically stimulated luminescence (SG TT-OSL) dated the opening of the Gran Dolina to roughly 900,000 years ago, and the sediments from TD4 to TD6 to between 890,000 to 770,000 years ago. These three units were probably deposited within a period of less than 100,000 years. Until 2013 with the discovery of the 1.4 million-year-old infant tooth from Barranco León, Orce, Spain, these were the oldest human fossils known from Europe, although human activity on the continent stretches back as early as 1.6 million years ago in Eastern Europe and Spain indicated by stone tools. Classification The face of H. antecessor is unexpectedly similar to that of modern humans compared to other archaic groups, so in their original description, Castro and colleagues classified it as the last common ancestor of modern humans and Neanderthals, supplanting H. heidelbergensis in this capacity. The facial anatomy came under close scrutiny in subsequent years. In 2001 French palaeoanthropologist Jean-Jacques Hublin postulated that the Gran Dolina remains and the contemporaneous Tighennif remains from Algeria (usually classified as Homo ergaster [=? Homo erectus], originally "Atlantanthropus mauritanicus") represent the same population, because fourteen of the fifteen dental features Castro and colleagues listed for H. antecessor have also been identified in the Middle Pleistocene of North Africa; this would mean H. antecessor is a junior synonym of "Homo mauritanicus", i. e., the Gran Dolina and Tighennif humans should be classified into the latter. In 2007 Castro and colleagues studied the fossils, and found the Tighennif remains to be much larger than H. antecessor and dentally similar to other African populations. Nonetheless, they still recommended reviving mauritanicus to house all Early Pleistocene North African specimens as "H. ergaster mauritanicus". In 2007 primatologist Esteban