OK, found this as a link within the Wikipedia page:
H. antecessor has been postulated as an evolutionary link between H. ergaster (1.9–1.4 Mya) and H. heidelbergensis (0.7–0.3 Mya). It is an open question whether H. antecessor is the last common ancestor of Neanderthals and anatomically modern humans, if it is entirely within the Neanderthal lineage, or an extinct lineage of its own.[3] Some authors consider H. antecessor an early form of H. heidelbergensis, which by the taxonomic principle of priority would extend the range of H. heidelbergensis to 1.2–0.3 Mya.[4]
The classification as a separate species is especially open to debate because no complete skull has been found, with only fourteen fragments and lower jaw bones known. Since the anatomical parallels to Homo sapiens were found in juveniles or children, the possibility has been argued “that H. antecessor adults didn’t really look much like H. sapiens at all”.[2][5]