Heterometra sp. (12-7-16 Birch Aquarium)

Description:

This crinoid was kept in a tank at Birch Aquarium (San Diego, California) and it's probably any tropical indopacific species, not necessarily native of California.It's the only time in my life that I see a non-fossil crinoid, so I need desperately a specific ID. The aquarium staff told me the genus, but after two years of asking from time to time about the species, I didn't received replies anymore.