Wow... It's been a minute since my organismal bio studies... But in really, really short terms- Gigantopithecus is not of any relation to the Heidlebergenesis. When I say no relation, I'm sure the phylogeny of it would put them much closer together than a lot of things. But ultimately, the 'G' one was a once hypothesized biped ape that live near Asia(china, india, etc). It was thought to be massive, 9ft+... But because of the lack of fossil remains, and depending on who you talk to it's been theorized that the indigenous people of china likely destroyed many of the remains as they were thought to be 'dragon bones' and were ground up for 'herbal remedies', there hasn't been conclusive evidence on the stature because no lower body fossils have yet to be found. Mostly jawbones etc etc. It has also since been thought that something that massive would be ridiculous, from an evolutionary standpoint, to stand upright, putting an insane amount of stress on a bipedal frame, thus making it more sensible to walk on all fours much like an ape. In contrast, 'H' one is a close link or "filling the gaps" between us (homo sapiens sapiens(no that's not a typo it's the new convention haha)) and H Neanderthalis, if I'm not mistaken. The fossil remains were found in Germany, thus the strangely German name. There is significant evidence of their lifestyle to the recovered remains including, but not limited to, right-handedness, stature 7ft ish, diet, tool making(which is a massive breakthrough) and earbones capable of ranges of sound( which supports the idea that they could communicate. Wow, that was alot. I think I felt it coming on. Clifnotes- g= big old ape, h= big old almost man. Green thumbs up anyone?