Thromidia

Thromidia is a genus of starfish in the family Mithrodiidae.

Description and characteristics
These are unusually massive sea stars with five sausage-shaped arms, containing probably the heaviest species of Asteroidea, up to 6 kg.

Species
There are four recognized species according to World Register of Marine Species:
 * Thromidia brycei Marsh, 2009 – Western Australia
 * Thromidia catalai Pope & Rowe, 1977 – West Pacific
 * Thromidia gigas (Mortensen, 1935) – South-west Indian ocean
 * Thromidia seychellesensis Pope & Rowe, 1977 – Seychelles