Sandra, its true there are different types of yoga. But when a model goes to a casting for a yoga shoot, there are some common yoga poses they are expected to be able to do.
As a photographer who has shot dozens of yoga magazine covers over the past nine years, I have been at more castings than I can remember. Maybe it would be helpful to models reading this to know the poses they may be asked to do for digital polaroids at a casting:
Standing split (UrdhvaPrasaritaEkaPadasana)
Handstand pose of some kind
Wheel or upward bow(UrdhvaDhanurasana)
Various pigeon poses