Pitekunsaurus macayai

Coria defined it as Aeolosaurini, but I don't agree since the caudal material doesn't appear to support this, in fact it's more in agreement with a lognkosaurian affinity, the anterior caudal looks like a Malawisaurus one. The extreme retrograde tilt in Aeolosaurini is totally absent here, as is the extreme elongation of the prezygapophyses like antennas that are a defining feature of aeolosaurini.

Comparing the dorsal and cervical vertebrae with all known titanosaurs, the closest correlation is with Puertasaurus and Futalognkosaurus in all aspects - centrum, neural spine, diapophyses, the compression of the anterior dorsals, the lack of bifid spines like opisthocoelicaudia or extreme backsweep of the neural spines as in "regular" saltasaurs and aeolosaurini. The femur head is the same way, similar to lognkosauria especially Futalognkosaurus in the high placement of the lateral bulge. It does not have the extreme deflection of the shaft sideways as in derived lithostrotia.

BTW Coria has been incorrect a few times before (most notably about putting Epachthosaurus in Andesauridae in the 1993 Argentinosaurus description paper). Epachthosaurus is quite a bit more derived than Andesaurus, in fact despite the hypantrum, it is likely even more derived than Lognkosauria. Given the fact that theories about relationships in titanosauria often change, the association of two such clearly different animals separated by so many characters would make aeolosaurini paraphyletic, much like Bonaparte and Coria's original definition of Andesauridae was paraphyletic.

With femur proportions, you could be right about the difficulty of brachiosaur mimicry. But that doesn't necessarily negate lognkosaurian affinity. Mendozasaurus is a longkosaur which doesn't "mimic" brachiosaurs and had shorter arms and probably a more horizontal neck posture.