Odontaster validus is a species of sea star in the family Odontasteridae. Its range includes the Southern Ocean and the seas around the mainland and islands of Antarctica. Description Odontaster validus can grow to about 10 cm (4 in) in diameter. The disc is broad, thick and cushion-like, creased by interambulacral grooves. There is a large madreporite near the centre and the surface is covered in small granulations organised in radial rows. The five short arms are wide at the base tapering sharply and the tip is often raised off the substrate showing the pale coloured tube feet beneath. The colour of the upper or aboral surface is plain red while the underside is pink. Distribution Odontaster validus is the most common sea star found in Antarctica. Its range includes the Antarctic Peninsula, the South Shetland Islands, the South Orkney Islands, South Georgia and the South Sandwich Islands, the Shag Rocks, the Prince Edward Islands and Bouvet Island. It is found at depths down to 900 metres. Biology Odontaster validus is an omnivorous scavenger and consumes anything it finds including carrion, detritus, the faeces of seals, red algae, bivalve shells, sponges, hydroids, other sea star, sea urchins, isopods, bryozoans, amphipods, crustacean larvae, ostracods, shrimps and diatoms. They have been observed aggregating on banks of mussels that have been exposed and damaged and on injured sea star, Acodontaster conspicuus. In turn, they are preyed upon by sea anemones and other species of sea star. It is an ecologically important species because of its consumption of benthic larvae and the control it exerts on the sea star Acodontaster conspicuus and the nudibranch Doris spp. which themselves tend to limit the growth of sponges that tend to dominate the seabed. Odontaster validus takes 3 to 6 years to reach maturity but may live for 100 years. This is a consequence of the animal being cold-blooded, the harsh environmental conditions in which it lives and the low metabolic rate that ensues. In McMurdo Sound, where it has been extensively studied, the water temperature is about . The initiation of oogenesis occurs from August to February and the eggs take about 18 months to mature. Spawning takes place between May and September and may be linked to seasonal changes in light levels, sunrise taking place in McMurdo Sound in August. The larval development is also slow with the first, bipinnaria, stage lasting 2 months. The