| Pie crust crab Temporal range: | |
|---|---|
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| Dorsal view | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Family: | Cancridae |
| Genus: | Metacarcinus |
| Species: | M. novaezelandiae |
| Binomial name | |
| Metacarcinus novaezelandiae | |
| Synonyms | |
| |
The pie crust crab (Metacarcinus novaezelandiae, formerly Cancer novaezelandiae), is a species of crab found around New Zealand and south-eastern Australia. [2]
In larval form Metacarcinus novaezelandieae consumes mostly tiny plankton. Once fully grown though they are primarily carnivorous, hunting nocturnally and preying on a variety of organisms. Molluscs (bivalves, gastropods and cephalopods) make up approximately one third of its diet and are its main food source; followed by crustaceans (amphipods, isopods, crabs and shrimp) which make up about 20% of its diet. Other food sources include small fish, sea anemones, sea sponges and algae. M. novaezelandieae hunts by using its powerful chelae to catch, kill, crush and access its prey, then feeds using its mouthparts. Its claws are capable of breaking open the tough shells of molluscs allowing the crab to reach the soft mollusc body inside and feed on it. Its claws allow it to effectively kill other forms of prey such as crustaceans as well. [3]
In larval form, Metacarcinus novaezelandieae is preyed upon by various fish species. As an adult, it has several main predators. Sea and shore birds (such as gulls) prey on crabs that expose themselves, often flying them up high and then dropping them to crack the tough crab exoskeleton. Larger fish with strong teeth prey upon these crabs under the water. Humans kill and eat these crabs when gathering food from the coast; as well as indirectly killing them from various industrial, scientific and commercial operations. [3]
New Zealand Maori have historically eaten crabs as part of their kai moana (food from the ocean) diet. Crabs were an easy resource to gather as they are often found in coastal shallows, making them easily accessible sea food. M. novaezelandieae is most likely among the many species of crabs the Maori ate, as it grows to a size large enough to be considered for eating, as well as being found throughout New Zealand. Sea food including M. novaezelandieae are still claimed by Maori today as a cultural food resource. [4]
Fossils of the species are known from the Miocene of New Zealand. [5]
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. They first appeared during the Jurassic Period.
Homarus gammarus, known as the European lobster or common lobster, is a species of clawed lobster from the eastern Atlantic Ocean, Mediterranean Sea and parts of the Black Sea. It is closely related to the American lobster, H. americanus. It may grow to a length of 60 cm (24 in) and a mass of 6 kilograms (13 lb), and bears a conspicuous pair of claws. In life the lobsters are blue, only becoming "lobster red" on cooking. Mating occurs in the summer, producing eggs which are carried by the females for up to a year before hatching into planktonic larvae. Homarus gammarus is a highly esteemed food, and is widely caught using lobster pots, mostly around the British Isles.
The Dungeness crab is a species of crab inhabiting eelgrass beds and water bottoms along the west coast of North America. It typically grows to 20 cm (7.9 in) across the carapace and is a popular seafood. Its common name comes from Dungeness Spit, United States, which shelters a shallow bay inhabited by the crabs.
Cancer pagurus, commonly known as the edible crab or brown crab, is a species of crab found in the North Sea, North Atlantic Ocean, and perhaps the Mediterranean Sea. It is a robust crab of a reddish-brown colour, having an oval carapace with a characteristic "pie crust" edge and black tips to the claws. A mature adult may have a carapace width up to 25 centimetres and weigh up to 3 kilograms. C. pagurus is a nocturnal predator, targeting a range of molluscs and crustaceans. It is the subject of the largest crab fishery in Western Europe, centred on the coasts of the British Isles, with more than 60,000 tonnes caught annually.
Carcinus maenas is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab, or green shore crab. In North America and South Africa, it bears the name european green crab.
The yellowbelly flounder is a flatfish of the genus Rhombosolea, found around New Zealand. A different species from the genus Rhombosolea is found in Australia and also goes by the name yellow-belly flounder. The Māori people have commonly fished for R.leporina, and many other species of flatfish, throughout New Zealand's coastal waters for hundreds of years. The Māori name for this species is 'pātiki tōtara'.
Metacarcinus anthonyi, the yellow rock crab or yellow crab, is a species of edible crab native to the Pacific coast of North America.
The New Zealand sand flounder is a righteye flounder of the genus Rhombosolea, found around New Zealand in shallow waters down to depths of 100 m.
A molluscivore is a carnivorous animal that specialises in feeding on molluscs such as gastropods, bivalves, brachiopods and cephalopods. Known molluscivores include numerous predatory molluscs,, arthropods such as crabs and firefly larvae, and, vertebrates such as fish, birds and mammals. Molluscivory is performed in a variety ways with some animals highly adapted to this method of feeding behaviour. A similar behaviour, durophagy, describes the feeding of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled molluscs, or crabs.
The pea crab, Pinnotheres pisum, is a small crab in the family Pinnotheridae that lives as a parasite in oysters, clams, mussels, and other species of bivalves.
Ovalipes catharus, commonly known as paddle crab and Māori: pāpaka, is a species of crab of the family Portunidae. It is found around the coasts of New Zealand, the Chatham Islands, and in south-eastern parts of Australia. Individuals from shallow waters, 0.1–0.5 metres (4–20 in) deep, have a carapace width of only 10–15 millimetres (0.4–0.6 in), while those from 5–15 m (16–49 ft) are 100–140 mm (3.9–5.5 in) wide.
Notomithrax ursus, known as the hairy seaweed crab, is a spider crab of the family Majidae.
Pagurus novizealandiae, or the New Zealand hermit crab is a hermit crab of the family Paguridae, endemic to New Zealand. Its body is up to 16 millimetres (0.63 in) wide.
Cancer productus, one of several species known as red rock crabs, is a crab of the genus Cancer found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest.
Durophagy is the eating behavior of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled mollusks, or crabs. It is mostly used to describe fish, but is also used when describing reptiles, including fossil turtles, placodonts and invertebrates, as well as "bone-crushing" mammalian carnivores such as hyenas. Durophagy requires special adaptions, such as blunt, strong teeth and a heavy jaw. Bite force is necessary to overcome the physical constraints of consuming more durable prey and gain a competitive advantage over other organisms by gaining access to more diverse or exclusive food resources earlier in life. Those with greater bite forces require less time to consume certain prey items as a greater bite force can increase the net rate of energy intake when foraging and enhance fitness in durophagous species.
Macroctopus maorum is known more commonly as the Maori octopus or the New Zealand octopus. They can also be known as Pinnoctopus cordiformis, is found in the waters around New Zealand and southern Australia. M. maorum is one of the largest and most aggressive octopus species living in the New Zealand and Australian waters. They feed mainly on crustaceans and fish. Although they have a short life span, the females lay thousands of eggs and are very protective of them.
Declawing of crabs is the process whereby one or both claws of a crab are manually detached before the return of the live crab to the water, as practiced in the fishing industry worldwide. Crabs commonly have the ability to regenerate lost limbs after a period of time, and thus declawing is viewed as a potentially more sustainable method of fishing. Due to the time it takes for a crab to regrow lost limbs, however, whether or not the practice represents truly sustainable fishing is still a point of scientific inquiry, and the ethics of declawing are also subject to debates over pain in crustaceans.
Portunus segnis, the African blue swimming crab, is a species of crustacean, a swimming crab belonging to the family Portunidae. While native to the western Indian Ocean, it is also invasive in the Mediterranean. It is thought to have come through the Suez Canal from the Red Sea but it may have been transported by ships.
Paguristes puncticeps is a hermit crab, in the family Diogenidae. It is found in shallow waters in the tropical western Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. Like other hermit crabs, it lives inside an empty mollusc shell, which it changes periodically as it grows.