New Star at Semakau!?

If someone were to show me the photo below and ask what star is it and my answer probably will be Cushion Star (Culcita novaeguineae).
If you also guess as Cushion Star....the answer is No!
This is the whole photo of the new star that I saw this evening at Semakau. The skin texture looks like cushion star however, the arms are too long to be a cushion star.
The underside do looks like a cushion star too.

Just look at the knob on the back...cushion star will not have such knobs! If you know the id of this sea star, please let me know. I'm so curious to find out the id. :-)