List of marine molluscs of New Zealand facts for kids

Where New Zealand is located

Cool shells from marine molluscs found at Akaroa Beach, New Zealand

This article is about the incredible marine molluscs of New Zealand. These amazing sea creatures are a big part of New Zealand's ocean life. They add to the country's rich biodiversity, which means all the different kinds of life found there.

Marine molluscs include many familiar animals. Think of sea snails and sea slugs, which are called gastropods. There are also bivalves like pipis, cockles, oysters, mussels, and scallops. And don't forget the clever octopuses and speedy squid! This list focuses only on the molluscs that live in the sea, not those found on land or in freshwater.

What are Marine Molluscs?

Molluscs are a huge group of animals. They have soft bodies, and many of them have a hard shell to protect themselves. They live in all sorts of places, from the deepest parts of the ocean to shallow coastal waters. New Zealand's long coastline and diverse marine environments make it a perfect home for many different types of molluscs. They play important roles in the ocean's food web. Some eat tiny plants, while others are hunters.

Different Kinds of Molluscs

Scientists group molluscs into different classes. Here are some of the main types you can find in New Zealand's waters:

Aplacophora: Tiny Worm-like Molluscs

Aplacophora are small, worm-shaped molluscs. They usually live in deep water and don't have a shell. They are often overlooked because of their size and habitat.

• Proneomenia quincarinata is one example found here.

Polyplacophora: The Chitons

Polyplacophora are also known as chitons. These molluscs have a unique shell made of eight overlapping plates. This design allows them to curl up for protection. They often cling tightly to rocks in the intertidal zone, where the tide goes in and out.

Some chiton families found in New Zealand include:

• Acanthochitonidae: These chitons often have spiny or hairy surfaces. An example is Cryptoconchus porosus.
• Mopaliidae: This family includes chitons like Plaxiphora australis.
• Chitonidae: This group has some of the most common chitons, such as Chiton glaucus. You might see them on rocks at the beach.
• Ischnochitonidae: These chitons are usually smaller and have a smoother appearance. An example is Ischnochiton maorianus.

Gastropoda: Snails and Slugs of the Sea

Gastropods are the largest group of molluscs. They include all the sea snails and sea slugs. Most gastropods have a single, coiled shell, but some, like sea slugs, have no shell at all. They move around on a muscular "foot."

Some interesting gastropods in New Zealand are:

• Nacellidae: This family includes limpets, which are cone-shaped snails that stick to rocks. Cellana radians, the golden limpet, is a common sight.
• Haliotidae: This family is famous for the paua, Haliotis iris. Paua are large, edible sea snails with beautiful iridescent shells.
• Trochidae: These are often called top snails because of their cone shape. Diloma subrostrata, the mudflat top shell, lives in muddy areas.
• Turbinidae: This group includes snails with thick, often colorful shells. The Astraea heliotropium, or circular saw shell, is known for its unique shape. The Lunella smaragda, or cat's eye, has a distinctive green operculum (the "door" that closes its shell).
• Littorinidae: These are the periwinkles, small snails that live on rocks in the splash zone. Austrolittorina antipodum, the banded periwinkle, is common.
• Ranellidae: This family includes large, predatory snails like the giant triton, Charonia tritonis.
• Buccinidae: These are the whelks, often scavengers. Cominella glandiformis, the mud whelk, is found in muddy estuaries.
• Volutidae: This family has some very beautiful shells, like the Alcithoe arabica, known as the Arabic volute.
• Janthinidae: These are the violet snails, like Janthina janthina. They float on the ocean surface using a raft of bubbles!

Bivalvia: Two-Shelled Wonders

Bivalves are molluscs with two hinged shells. They don't have a head or a radula (a tongue-like organ for scraping food). Instead, they filter food from the water.

Common bivalves in New Zealand include:

• Mesodesmatidae: This family includes popular shellfish. The Paphies australis is the well-known pipi. The Paphies subtriangulata is the tuatua, and Paphies ventricosa is the toheroa.
• Veneridae: This group includes many clams and cockles. Austrovenus stutchburyi is the common New Zealand cockle.
• Ostreidae: These are the oysters. Tiostrea chilensis is the famous Bluff oyster, known for its delicious taste.
• Pectinidae: These are the scallops. Pecten novaezelandiae is the New Zealand scallop.
• Mytilidae: This family includes mussels. Perna canaliculus is the New Zealand green-lipped mussel, which is farmed for food.

Scaphopoda: Tusk Shells

Scaphopods are also called tusk shells because their shells are shaped like tiny elephant tusks. They live in sand or mud on the seafloor, with their narrow end sticking up into the water. They use tentacles to catch small food particles.

• Dentalium zelandicum is one of the tusk shells found in New Zealand.

Cephalopoda: Smart Ocean Hunters

Cephalopods are the most advanced molluscs. This group includes octopuses, squid, and cuttlefish. They have a distinct head, large eyes, and tentacles or arms. Many can change color quickly to hide or communicate.

Some amazing cephalopods in New Zealand waters are:

• Spirulidae: The Spirula spirula, or ram's horn squid, has a small, coiled internal shell.
• Sepiolidae: This family includes bobtail squid, like Iridoteuthis maoria.
• Cranchiidae: This family is home to some of the largest squid. The Mesonychoteuthis hamiltoni is the incredible colossal squid, one of the biggest invertebrates on Earth!
• Octopodidae: This family includes octopuses. Pinnoctopus cordiformis is the common New Zealand octopus.
• Argonautidae: This group includes the paper nautilus, Argonauta nodosa, which is actually an octopus that builds a beautiful, thin "paper" shell to carry its eggs.

Images for kids

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  Location of New Zealand

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  Diversity of marine mollusc shells at Akaroa Beach, New Zealand

See also

• List of non-marine molluscs of New Zealand
• List of marine molluscs of Australia