That is most intriguing. The spores are classic starkeanum. Flora Briofitica Iberica says that sp can have just a basal membrane and no teeth. Does yours totally lack a peristome?
I'll double check for a peristome, but I thought the ornamentation looked more globular than typical starckeanum?
Yes a rudimentary peristome is present on some capsules, so starckeanum is correct thanks.