These sea stars have extremely elongated spines along their arms, as seen in this one individual from Kahalewai seamount.
Elongated Spines
Image courtesy of the NOAA Office of Ocean Exploration and Research, Mountains in the Deep: Exploring the Central Pacific Basin. Download larger version (jpg, 1.6 MB).

These sea stars have extremely elongated spines along their arms, as seen in this one from Kahalewai seamount.

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