Allostichaster

Allostichaster is a genus of sea stars in the family Asteriidae. The genus was first established in 1917 by Walter Kenrick Fisher, an American marine biologist known for his work on starfish. These starfish are commonly found in the Southern Hemisphere, primarily in Australia and New Zealand.

Orange Splitting Star, Three And Three Star – Allostichaster insignis

Four And Four Starfish, Many-armed Seastar – Allostichaster polyplax

Allostichaster capensis

Common Names

Common names for species within this genus include:

  • Spiny starfish
  • Rough starfish
  • Chocolate starfish

Characteristics

Allostichaster species exhibit a number of distinguishing characteristics:

  • Body shape: Typically have a pentagonal or star-shaped body with five arms.
  • Size: Can range in size from a few centimeters to over 20 centimeters in diameter.
  • Coloration: Often exhibit a mottled or speckled appearance, with colors ranging from brown to reddish-brown, sometimes with yellow or orange highlights.
  • Surface texture: Their upper surface is covered in numerous spines, giving them a rough texture. Some species may also have small, granular bumps.
  • Tube feet: Allostichaster starfish possess tube feet, which are used for locomotion and feeding. These tube feet are located on the underside of the arms.

Environments

Allostichaster species are predominantly found in marine environments, typically inhabiting rocky reefs and intertidal zones. They are often found in areas with moderate water flow and good availability of food. Some species may also inhabit sand or mud bottoms.

References