Red Knob Sea Star

The Red Knob Sea Star (Protoreaster linckii) is a starfish. It is a marine (saltwater) invertebrate, because it does not have a backbone. It is also known as the Red Knob Starfish, the Red Spine Star, or the African Red Knob Sea Star. It is not a fish, so scientists prefer to say that it is a sea star.

The Red Knob Sea Star has five elongated tube limbs, called arms or feet. It has several bright red tubercles on its arms. It has a grey body with red stripes that connect the tubercles. 

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Spineless Sea Urchin

The Spineless Sea Urchin (Abatus cordatus) is a marine (saltwater) invertebrate echinoderm. It is also known as the Kangaroo Sea Urchin because the female keeps her eggs in a pocket or pouch. It is related to starfish (sea stars). 

The Spineless Sea Urchin has a hard, spherical (ball-shaped) shell, called a test, with no backbone and no spines sticking out of its body (like the Spiny Sea Urchin). Its mouth, with a small jaw, is in the centre of the urchin on its underside. It does not have eyes. It is sensitive to touch, light, and chemicals, due to the numerous sense cells around its mouth.

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Brittle Star

The Bristle Star (Ophiomastix janualis) is a tropical marine (saltwater) echinoderm, related to the starfish. It is also called a Serpent (Snake) Star. It is not a fish. It is an invertebrate (animal with no backbone) and an ophiuroid.

The Bristle Star has five long, slender whip-like arms radiating symmetrically from a central coin-shaped or disc-shaped body. The body contains its mouth and internal organs. Its mouth, on the underside of the body, has five toothed jaws. Its mouth is both the entrance to its internal organs and the exit to release waste.

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Sea Urchin

The Sea Urchin is a spiny marine (saltwater) echinoderm. It is an animal that lives on the bottom of the ocean. It is related to starfish (sea stars). It is also called a Sea Hedgehog.

The Sea Urchin has a hard shell, called a test. It is spherical (round like a globe), shiny and spiny. Young urchins have bilateral symmetry, and as they become adults, they have fivefold symmetry (similar to starfish with five appendages). Its mouth, with a small jaw, is in the centre of the urchin on its underside.

It does not have eyes. It is sensitive to touch, light, and chemicals, due to the numerous sensitive cells in its spines, tube feet, and around its mouth.

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Starlet Cushion Starfish

The Starlet Cushion Starfish (Asterina gibbosa) is a small marine (saltwater) invertebrate (without an inner skeleton) echinoderm. It is not a fish.  Zoologists prefer to call it the Starlet Cushion Sea Star.

The Starlet Cushion Starfish has five short blunt arms and a puffy appearance that looks like a cushion. Its upper surface has short, sharp spines. It can be blue, brown, green, or orange. Its mouth is on its underside in the centre.

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Starfish

The Starfish (Pentaceraster mammillatus) is a five-limbed marine animal. It is also called the Sea Star, because it is not a fish. It is an invertebrate animal, because it has no backbone.

The Starfish can be various colours, such as green, yellow, purple, pink and grey. It has a thick body with rounded tubercles (lumps) on its surface – often of a different colour to its body. It has five limbs radiating from a central point (its mouth) in a star-shape. Its mouth is on the underside of its body.

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Dalmatian Linckia Starfish

The Dalmatian Linckia (Linckia multifora) is a starfish, a marine (saltwater) invertebrate, because it has no backbone. It is also called the Spotted Linckia or Multicolour Sea Star. It is not a fish.

The starfish is an echinoderm (meaning prickly skin) in the Asteroidea class (meaning star-shaped).

It has five elongated tube limbs (feet or arms) pink or reddish mottled with white and yellow colours that taper slightly towards the tips.

The surface has a rough texture and is covered in granulations.

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Blue Star

The Blue Star starfish (Linckia laevigata) is also called the Blue Linckia. It is a marine (saltwater) invertebrate, because it has no backbone.

The starfish (also called a sea star) is an echinoderm (meaning prickly skin) in the Asteroidea class (meaning star-shaped).

It has five elongated tube limbs (feet or arms) that are dark or light blue with tips at each of the limb.

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