Like A. planci, however, its distinctive traits include being disc-shaped, multiple-armed with multiple madreporites, flexible, prehensile, and densely spined, and having a large ratio of stomach surface to body mass.

Its prehensile ability arises from the two rows of numerous tube feet that extend to the tip of each arm.

Madsen (1955) reviewed the taxonomy of the genus Acanthaster and concluded that there were three species: the Indo-Pacific A. planci(L.); the short-armed, blunt spined eastern Pacific A. ellisii (Gray) and A. brevispinus Fisher.

[7] They considered it sufficiently different from the holotype in some features to describe it as A. brevispinus seyshellesensis nov. subsp.

Scallops would seem to be difficult prey for slow-moving starfish with their rapid swimming by 'flapping' their valves and with 'eyes' on their mantle edges.

After trapping a scallop, the starfish fed and digested it while adopting a characteristic arched posture.

[6] In 1973, Lucas and Jones conducted a hybridization experiment to investigate genetic relatedness between A. brevispinus and A. planci.

Specimens of A. brevispinus were obtained by trawling in December of that year, near the approximate time of annual gamete release by A. planci in Great Barrier Reef waters.

The larvae were reared according to the methods employed for A. planci[8] and developed through the typical larval stages of bipinnaria and brachiolaria.

The hybrid starfish reached sexual maturity at the end of their second year (summer spawning season in the field).

Further crosses were undertaken with these F1 generation hybrids to determine the extent to which gene flow through interbreeding could occur between the two species.

Although high fertilization rates were achieved again, without evidence of gamete incompatibility, survival was poor through early development and some morphological abnormalities occurred that had not been seen previously in batches of juvenile starfish.