Homarus Temporal range: Albian–Recent |
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Homarus gammarus | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Crustacea |
Class: | Malacostraca |
Order: | Decapoda |
Family: | Nephropidae |
Genus: | Homarus Weber, 1795 |
Type species | |
Astacus marinus Fabricius, 1775 |
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Extant species | |
H. americanus – American lobster |
Homarus is a genus of lobsters, which include the common and commercially significant species Homarus americanus (the American lobster) and Homarus gammarus (the European lobster).[1] The Cape lobster, which was formerly in this genus as H. capensis, was moved in 1995 to the new genus Homarinus.[2]
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Homarus is one of three extant genera of clawed lobsters to show dimorphism between claws – a specialisation into a crushing claw and a cutting claw. The other similar genera are Nephrops, which is much more slender, and has grooves along the claws and the abdomen, and Homarinus, the Cape lobster from South Africa, which is even smaller, and has hairy claws.[3]
Comparison of the two extant species
Eight extinct species are known from the fossil record,[4] which stretches back to the Cretaceous,[5] but only two species survive. These two species, the American lobster and the European lobster, are very similar and may have speciated as recently as the Pleistocene, during climatic fluctuations.[5] The best characters for distinguishing them are the geographic distribution, with the American lobster in the western Atlantic and the European lobster in the eastern Atlantic, and by the presence of one or more teeth on the underside of the rostrum in H. americanus but not in H. gammarus.[6]
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.[7] 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.[7] In life, the lobsters are blue, only becoming "lobster red" on cooking.[8] Mating occurs in the summer, producing eggs which are carried by the females for up to a year before hatching into planktonic larvae.[9] Homarus gammarus is a highly esteemed food, and is widely caught using lobster pots,[7] mostly around the British Isles.[10]
The American lobster, Homarus americanus, is found on the Atlantic coast of North America.[11] It is found as far south as North Carolina, but is famously associated with the colder waters around the Canadian Maritimes, Newfoundland and Labrador, Maine, Massachusetts, Rhode Island and New Hampshire.
They commonly range from 20–60 cm (8–24 in) in length and 0.5–4.1 kg (1.1–9.0 lb) in weight, but have been known to reach lengths of well over 1 m (3 ft 3 in) and weigh as much as 20 kg (44 lb) or more, making this the heaviest marine crustacean in the world.[12] An average adult is about 23 cm (9 in) long and weighs 700–900 g (25–32 oz).[13]
The boundaries between Homarus and the extinct genus Hoploparia are unclear, and some species, such as Hoploparia benedeni have been transferred between the two genera. Eight species have been assigned to Homarus from the fossil record.[14] They are:[15][Note 1]