In the image on the left is Moilanen arc among other halos. On the right is similar looking halo (arrow), but its V is more pointed and it is also closer to the sun, about 7 degrees above it. These are stacked images, the inset image is a single frame showing the same arc (and also a weak Moilanen arc above it).
This halo seems to be what could be called a "reflected lower sunvex Parry arc". It was Walt Tape who suggested this kind of explanation for the arc. I will later add a post with simulations, crystal figures and raypaths. Pictures of the halo were published today in Tähdet ja avaruus magazine in Finland.
*** addition 5 December: see the upcoming posting on Les Cowley's site ( 1 ), which lights up the formation of this arc ***