Phalanx question

Why is the Carthaginian phalanx much more coherent? I mean if you group units of the elite african pikemen to create a wall of spears, they have no gaps between them. But if you do this with successor phalanxes, there is a small gap between each unit. Wouldn't that be considered a weakness? I'm wondering if this was made for a purpose or is it just a fluke?

Perhaps the unit doesn't include officer/standard bearer? Those are what cause the "gaps" between hellenic phalangitai, as they stand on the left side of the pikemen.

It's funny you should mention that - another topic elsewhere mentions that the Lybian phalanx has no officer (in some cases?). Could be something related.