I utilize a device in forensics that promotes theory, no matter the fallout.
Investigations take too long. Why? Generally because they proceed based on fossilized methods of inquiry.
Instead of waiting until the conclusion is "inescapable", the use of imminent analysis encourages all present to think, quickly, and forensically.
The piece is quite obviously ribs, likely because of their proximity to each other, outboard on the wing, and may be in the leading edge domain.
The piece has other characteristics. The gross shape suggests a symmetry found in mountings, "U-shape". Relief of material to save weight, but depending on the resolution of the photography, it also appears heavier than rib material (thicker).
In considering and rejecting discussion, not only is progress attained, but an encouragement to think outside the "box" is instructive.
We do round tables, no opinion is judged, instead it is objectively evaluated.
Many opportunities to find the truth are lost in waiting for the solution to "appear". It is a process, not magic.