Invertebrate

A spider

An invertebrate is an animal that does not have a spinal column or backbone. This contrasts with vertebrate: if an animal is not a vertebrate (fish, reptile, amphibian, bird, or mammal), it is an invertebrate. Most animals, and most species of animal, are invertebrates.

The main phyla (groups) of invertebrate animals are:

• Annelida: segmented worms
• Arthropods: (arachnids, crustaceans, insects, and others); the largest groups of invertebrates.
• Brachiopods: the lamp-shells.
• Bryozoa: sea mats or moss animals (sometimes they look like corals)
• Cnidarians: jellyfish, sea anemones, hydroids.
• Echinoderms: starfish, sea urchins, sea cucumbers
• Molluscs: (gastropods, cephalopods, bivalves and others); a large group of invertebrates.
• Nematoda: roundworms
• Porifera: sponges
• Platyhelminthes: flatworms
• Rotifers: tiny "wheel animals", which live in habitats such as pond water.

Insects and other arthropods have no bones, but they have a skeleton on the outside of their bodies, called an exoskeleton.

There are 18 more groups of invertebrates, mostly minor: see List of animal phyla.

Invertebrate Media

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  European Wasp on a white background. Specimen is about 12mm. Taken in Swifts Creek, Victoria, Australia.

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  A 9 millimeter-long female jumping spider found in Newport News, Virginia.The lens setup utilized was a Nikon 50mm f/1.4D reverse mounted on a Nikon 70-300mm f/4-5.6G .*13 images of variable focus were captured and composited in CombineZM, a focus stacking program.

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  Picture of a grapevine snail.

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  J J Wild Pseudocarcinus cropped

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  A live individual of Argopecten irradians, the Atlantic Bay scallop, photographed at the Marine Biological Laboratory in Woods Hole

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  A variety of corals form an outcrop on Flynn Reef, part of the Great Barrier Reef near Cairns, Queensland, Australia.

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  Sepia officinalis

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  An Oroperipatus species found in Yasuni National Park, Ecuador

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  Carcinoscorpius rotundicauda (mangrove horseshoe crab)

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  Tracheal system of dissected cockroach. The largest tracheae run across the width of the body of the cockroach and are horizontal in this image. Scale bar, 2 mm.