Diference between altum and scalare.besides,?

besides the markings/stripes,what are the other physical differences between pterophtlum altum and scalare?

Wild types can be tricky to differentiate and they even vary from where they are collected.

Wild-type scalare:
http://www.fishbase.org/Photos/PicturesS...

Wild-type altum:
http://www.fishbase.org/Photos/PicturesS...

The head shape on the altum is a little different to the scalare. I believe altums are a bit taller than scalare's when full grown. Altums are also more sensitive to water parameters in captivity.