This is an Asterina. Number of arms and coloration are not diagnostic, and even seastar experts would have trouble identifying them to species.
As for the link, hmmm. I guess you are right there
and I won't even complain about being asked to change it.
Let me quote
D. Fujita1
The sea star Asterina pectinifera causes deep-layer sloughing in Lithophyllum yessoense (Corallinales, Rhodophyta)
Hydrobiologia Volume 398-399, Number 0 / April, 1999
(1) Toyama Prefectural Fisheries Research Institute, Namerikawa, 936-8536, Japan
Abstract Deep-layer sloughing is a recently described mode of surface shedding in some encrusting coralline algae. Several causative agents or ecological roles have been suggested for its occurrence, but none have been proven. During ecological studies of urchin-dominated barren grounds in southwestern Hokkaido, the dominant encrusting coralline species, Lithophyllum yessoense, was found to be sloughing beneath the sea star, Asterina pectinifera, in shallow waters. The sea stars often stayed long in one position and left body-shaped white scars on the encrusting thalli. Anatomical studies of the scars revealed that a deep layer, well below the vegetative initials and the bottom of submerged conceptacles, was being shed. The upper layer of living columnar cells in the medulla became new vegetative initials, producing new epithallial layers above them. Deep-layer sloughing also occurred on the thalli in running-water aquarium experiments, when thalli were exposed to the sea stars. Althou gh the thalli were heavily covered with small epiphytic algae, clean surfaces were found just below the flakes of the sloughed layer. This mode of surface shedding may play an important role in recovery from damage on barren grounds where bottom feeders are abundant.
Asterina pectinifera - Corallinales - Lithophyllum yessoense - regeneration - sea star - sloughing
