hmm, so... given that sidonia no kishi, winged armor suzumega and abara do actually share the "gauna", the end of humanity and so on, i think these connections are more than just messing around with names and characters. and sidonia no kishi is kind of a sequel of abara trough suzumega.

sure, but ABARA - Winged Armor Suzumega - Sidonia no Kishi are sequential in time. altough centurys passed between the three. my opinion is, that in ABARA the destroyed earth and the Gaunas that appeard are the same as later in Suzumega, the gigantic Gaunas and the long lost home planet. and in Sidonia, the same but in a serialized form. and with more emphasis on the mecha.

Could very well be, though just the reuse of one term doens´t neccesarily mean continuity. Like in the case of Blame and Biomega, both had Toha industries, remember?

yes, but my point is: not only a name, or a character is reused. it's the a new civilization what we see in Suzumega after the apocalypse in Abara, and Sidonia that war of the new human civilization is depicted in space. centuries after the destruction of 'home' and the rise of the Gaunas.
point is: it makes sense this way! nihei may be creating a new universe. would be good :]

Personally, I doubt there is any relation other than the term 'Guana' other than perhaps Suzumega perhaps being the inspiration behind Cyndonia. There was this same confusion with Biomega and BLAME!, as both worlds share 'Toha Heavy Industries.' We also see this sort of link between one-shots and longer series quite often. Digimortal=Abara (we even got Digimortal in the back of Abara Vol2) Deadheads=Biomega, and now Suzumega=Cyndonia.

Abara cannot take place on Earth, at least as we know it, as at the very end we see what their world is: a flat stretch of rock floating in space and by no means a planet.

But really, even if the universes are linked, what would this knowledge accomplish? Until there is some sort of refference that leaves a loose end, possibly that ties in to one of the other mentioned stories, attempting to link the stories together essentially serves no purpose.

Abara, Suzumega and Sidonia could be all part of the same universe without any problem. First, because "Gauna" is not only a name common in all of them, but is also a kind of creature with the same powers, structure, concept, etc. Second, in all of them, at least in Sidonia and Suzumega, Earth is missing and was destroyed by the Gaunas; in Abara, if the Earth wasn't destroyed the scenario is much like the other two: a bunch of humans floating in space in a weird kind of spaceship fighting against Gaunas.

But none of this means they all are part of the same universe or any kind of temporal succession between them, if they really are. Actually I think that Suzumega is to Sidonia what Digimortal is to Abara, an essay or early concept that was amplied later.

In the end probably I will be wrong and at Blame's 30rd aniversary we will all discover that Blame, Biomega, Abara, Suzumega, Sidonia and Zeb-Noid are all part fo the same universe, just like a crap Gundam series made in 1999. ;D

http://en.wikipedia.org/wiki/Cameo_appearance
try thinking about that