Hi - There are 4 distinguishing factors that Pogona Barbata (Eastern) have that Vitticeps(Central) don't:
No.1 : 3 grey dots on their nose, 2 at the tip & one behind. Some say only babies have this, but this is by 3 yr old Big Fella.
No. 2 is the triangular head as noted above, very different from the Vitticeps
They also have:
the more symetrically ridged tail, more specific than on the Vitticeps
Big Fella wouldn't accommodate me with opening his mouth, but the distinctive bright yellow mouth, as compared with the pinker colour of the vitticeps, is the 4th & most distinguishing. I have also found from having both species that the Barbata's "Bearding" is not near as spectacular/rounded as the Vitticeps.
If you've had a discussion with someone who is arguing the yellow mouth, not only has BigFella got it, but the 3 wild Barbata we have had in our yard just this yr, in an area where Barbata's live naturally, so I can't understand your confusion there?
Hope that helps! Kathy