Homarus

Life-forms

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Crustacea
Superclassis: Multicrustacea
Classis: Malacostraca
Subclassis: Eumalacostraca
Superordo: Eucarida
Ordo: Decapoda
Subordo: Pleocyemata
Infraordo: Astacidea
Superfamilia: Nephropoidea

Familia: Nephropidae
Subfamilia: Nephropinae
Genus: Homarus
Species (10): H. americanus – H. gammarus – †H. brittonestris – †H. davisi – †H. hakelensis – †H. lehmanni – †H. mickelsoni – †H. morrisi – †H. neptunianus – †H. travisensis
Name

Homarus Weber, 1795

Type species: Astacus marinus Fabricius, 1775 (=Cancer gammarus Linnaeus, 1758)

Fixation: subsequent designation by Fowler, 1912, Annual Report New Jersey State Museum, 1911: 333.

References
Primary references

Weber, F. 1795. Nomenclator entomologicus secundum Entomologiam Systematicam ill. Fabricii adjectis speciebus recens detectis et varietatibus. Carolum Ernestum Bohn, Chilonii et Hamburgi [= Kiel & Hamburg]. viii + 171 + [1] pp. [available work: ICZN 1956. Opinion 17, Direction 32] BHL Reference page. [See page 94.]

Additional references

Herrick, F.H. 1895. The American Lobster: a study of its habits and development. Bulletin U.S. Fish Commission 5: 1–252, text figs 1–40, pls 1–54. BHL Reference page.

Links

Homarus – Taxon details on Integrated Taxonomic Information System (ITIS).

Vernacular names
العربية: شاكوك, سرطان البحر
беларуская: Омар (Omar)
bosanski: Jastog
čeština: Humr
dansk: Hummer
Deutsch: Hummer
dolnoserbski: Rakownica
Ελληνικά: Αστακός (Astakós)
English: Lobsters
Esperanto: Omaro
español: Langosta
suomi: Hummeri
français: Homard
hrvatski: Jastog
hornjoserbsce: Rakownica
Kreyòl ayisyen: Oma
magyar: Homár
interlingua: Homaro
íslenska: Humar
italiano: Astice
lietuvių: Vėžys
latviešu: Vēzis
македонски: Ја́стог (Jástog)
Nederlands: Hommer
norsk: Hummer
occitan: Ligombau
polski: Homar
português: Lagosta
rumantsch: Giomber da mar
română: Homar
русский: Омар
slovenščina: Homár
shqip: Karavidhe
српски / srpski: Јастог (Jastog)
svenska: Hummer
українська: Омар (Omar)

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]
Description

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]

While analyses of morphology suggest a close relationship between Homarinus and Homarus, molecular analyses using mitochondrial DNA reveal that they are not sister taxa.[4] Both genera lack ornamentation such as spines and carinae, but are thought to have reached that state independently, through convergent evolution.[4] The closest living relative of Homarus is Nephrops norvegicus, while the closest relatives of Homarinus are Thymops and Thymopides.[4]
Species

Eight extinct species are known from the fossil record,[5] which stretches back to the Cretaceous,[6] 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.[6] 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.[7]

Image	Scientific name	Common Name	Description	Distribution
	Homarus gammarus Linnaeus, 1758	European lobster or common lobster	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.[8] In life, the lobsters are most of the time blue, only becoming "lobster red" on cooking.[9] Homarus gammarus is a highly esteemed food, and is widely caught using lobster pots,[8]	Mostly around the British Isles.[10]
	Homarus americanus H. Milne-Edwards, 1837	Atlantic lobster, Canadian lobster, true lobster, northern lobster, Canadian Reds, or Maine lobster.	commonly ranges 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 64 cm (25 in)[11] 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).[11]	Atlantic coast of North America, from Labrador in the north to Cape Hatteras, North Carolina in the south

Fossil species
Fossil of Hoploparia bearpawensis; the relationships between Homarus and Hoploparia remain unclear.

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.[13] They are:[14][Note 1]

Homarus brittonestris Stenzel, 1945 – lower Turonian
Homarus davisi Stenzel, 1945 – lower Turonian
Homarus hakelensis (Fraas, 1878) – Cenomanian
Homarus lehmanni Haas, 1889 – Rupelian
Homarus mickelsoni (Bishop, 1985) – lower Campanian
Homarus morrisi Quayle, 1987 – Eocene
Homarus neptunianus Polkowsky, 2004 – Oligocene
Homarus travisensis Stenzel, 1945 – middle Albian

Distribution

The two extant species of Homarus are both found in the North Atlantic Ocean. H. americanus is found from Labrador to North Carolina in the western North Atlantic,[16][17] while H. gammarus is found from Arctic Norway to Morocco, including the British Isles and the Mediterranean Sea.[8][16]
Life cycle
Zoea larva of H. gammarus

Mating in Homarus is complex and is accompanied by a number of courtship behaviours.[16] Males build mating shelters or burrows, and larger males can attract more females, producing a polygynous mating system.[16] A few days before moulting, a female will choose a mate, and will remain in his shelter until the moult. The male will then insert a spermatophore into the female's seminal vesicle, where it may be stored for several years.[16] The eggs of Homarus species are laid in the autumn, being fertilised externally as they exit, and are carried by the female on her pleopods.[16]

The eggs generally hatch in the spring as a pre-larva, which rapidly develops into the first larval phase.[16] This is followed by three zoeal phases, the total duration of which can vary from two weeks to two months, depending on the temperature.[16] At the following moult, the young animal becomes a post-larva, with a gross form resembling the adult lobster.[16] Although it can swim, using its pleopods, the post-larva soon settles to the bottom and lives as a juvenile for 3–5 years.[16]

As adults, Homarus species moult increasingly infrequently. The size at sexual maturity varies with temperature; it is around 70 mm (2.8 in) for female H. americanus in southern New England, but 100 mm (3.9 in) around the Bay of Fundy.[16] In H. gammarus, the size at sexual maturity is less well defined, but is in the range 80–140 mm (3.1–5.5 in).[16]
Notes

Stratigraphic ranges are from Tschudy (2003)[13] and Polkowsky (2004).[15]

References

"Homarus Weber, 1795". Integrated Taxonomic Information System. Retrieved June 25, 2011.
Irv Kornfield; Austin B. Williams; Robert S. Steneck (1995). "Assignment of Homarus capensis (Herbst, 1792), the Cape lobster of South Africa, to Homarius new genus (Decapoda: Nephropidae)" (PDF). Fishery Bulletin. 93 (1): 97–102.
Subfamily Nephropinae Dana, 1852[permanent dead link], pp. 51–86 in Holthuis (1991).
Dale Tshudy; Rafael Robles; Tin-Yam Chan; Ka Chai Ho; Ka Hou Chu; Shane T. Ahyong; Darryl L. Felder (2009). "Phylogeny of marine clawed lobster families Nephropidae Dana, 1852, and Thaumastochelidae Bate, 1888, based on mitochondrial genes". In Joel W. Martin; Keith A. Crandall; Darryl L. Felder (eds.). Decapod Crustacean Phylogenetics. CRC Press. pp. 357–368. doi:10.1201/9781420092592-c18. ISBN 978-1-4200-9258-5.
Sammy De Grave; N. Dean Pentcheff; Shane T. Ahyong; et al. (2009). "A classification of living and fossil genera of decapod crustaceans" (PDF). Raffles Bulletin of Zoology. Suppl. 21: 1–109. Archived from the original (PDF) on 2011-06-06.
Matthias Obst; Peter Funch; Gonzalo Giribet (2005). "Hidden diversity and host specificity in cycliophorans: a phylogeographic analysis along the North Atlantic and Mediterranean Sea". Molecular Ecology. 14 (14): 4427–4440. doi:10.1111/j.1365-294X.2005.02752.x. PMID 16313603. S2CID 26920982.
Key to species of the genus Homarus. p. 57. Archived from the original on 2008-06-08. Retrieved 2006-12-02. In Holthuis (1991).
Lipke B. Holthuis (1991). "Homarus gammarus". Marine Lobsters of the World. FAO Species Catalogue, Volume 13. FAO Fisheries Synopsis No. 125. Food and Agriculture Organization. p. 60. ISBN 92-5-103027-8. Archived from the original on 2010-09-10.
Alan Davidson (2004). "Lobster (both European and American)". North Atlantic Seafood: A Comprehensive Guide with Recipes. Ten Speed Press. pp. 188–189. ISBN 978-1-58008-450-5.
"Fishery Statistical Collections. Global Production". Fisheries Global Information System. Food and Agriculture Organization. Retrieved September 30, 2010.
Homarus americanus. p. 58. Archived from the original on 2011-06-08. In Holthuis (1991).
"Heaviest marine crustacean". Guinness World Records. Archived from the original on May 28, 2006. Retrieved August 3, 2006.
Dale Tshudy (2003). "Clawed lobster (Nephropidae) diversity through time". Journal of Crustacean Biology. 23 (1): 178–186. doi:10.1651/0278-0372(2003)023[0178:CLNDTT]2.0.CO;2. JSTOR 1549871. S2CID 85905108.
Carrie E. Schweitzer; Rodney M. Feldmann; Alessandro Garassino; Hiroaki Karasawa; Günter Schweigert (2010). Systematic List of Fossil Decapod Crustacean Species. Crustaceana monographs. Vol. 10. Brill. ISBN 978-90-04-17891-5.
S. Polkowsky (2004). "Decapode Krebse aus dem oberoligozänem Sternberger Gestein von Kobrow (Mecklenburg)". Tassados. Schwerin: privately published. 1: 1–126.
J. Stanley Cobb; Kathleen M. Castro (2006). "Homarus species". In Bruce F. Phillips (ed.). Lobsters: Biology, Management, Aquaculture and Fisheries. John Wiley & Sons. pp. 310–339. ISBN 978-1-4051-2657-1.

Gro I. van der Meeren, Josianne Støttrup, Mats Ulmestrand & Jan Atle Knutsen (2006). "Invasive Alien Species Fact Sheet: Homarus americanus" (PDF). Online Database of the North European and Baltic Network on Invasive Alien Species. NOBANIS. Retrieved May 4, 2011.

Bibliography
Lipke B. Holthuis (1991). Marine Lobsters of the World. FAO Fisheries Synopsis. Vol. 125. Rome: Food and Agriculture Organization. ISBN 978-92-5-103027-1.