Jaw bone discovered in Ethiopia is oldest known human lineage remains
theguardian.com
theguardian.com
Sparsely sampled distributions will necessarily have tails that are not represented in the sampled data, and for early humans those tails could plausibly go back much, much further than the current record shows.
As such, we can expect that there will be a slow, steady stream of "surprising" early finds that push back hominid evolution to much longer ago than previously appreciated. The same is true of dinosaurs or any other species: the rarity of fossilization events is such that the probability of the earliest surviving fossil being particularly close to the emergence of the species is just not that high.
It would be interesting to do a serious analysis of the fossil discovery distribution to see if we can make a better estimate of the earliest emergence of hominids based on empirical estimates of fossilization and discovery probabilities.
Surely someone's done this? It's reminiscent of the tank problem.
Might be slightly off-topic.
One important thing to keep in mind is that species are hypotheses that can be tested, and the interpretations can vary from person to person and field to field. For example, many molecular geneticists will often discover new cryptic species on the basis of their DNA sequences, that a morphologist might not consider to be a true species. For fossils, of course, there almost always only morphological evidence for species.
The relative roles of anagenesis (change within a species) and cladogenesis (splitting event that creates two new species) in evolution is still being investigated, especially by paleontologists. One of many problems is that the fossil record is extremely incomplete, and so it's difficult to determine whether anagenesis or cladogenesis dominates. For me (as a non-paleontologist) my simplifying assumption about evolution is that anagenetic change doesn't occur, but again this is still an area of active research.
Trilobite fossils are older human lineage remains, or at least plenty of species we know led to mammals, if trilobites didn't descend to us.
The article specifies "... that belong to the genus Homo, the lineage that ultimately led to modern humans," which is probably what the headline meant.