Homarus

Homarus
Temporal range: Albian–Recent
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
Extant species

H. americanusAmerican lobster
H. gammarus – European 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]

Contents

[hide]

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]

Species

Comparison of the two extant species

H. gammarus
H. americanus

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

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]

Homarus americanus

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]

Fossil species

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]

Notes

  1. ^ Stratigraphic ranges are from Tschudy (2003)[14] and Polkowsky (2004).[16]

References

  1. ^ "Homarus Weber, 1795". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=97313. Retrieved June 25, 2011. 
  2. ^ 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. http://fishbull.noaa.gov/931/kornfield.pdf. 
  3. ^ Subfamily Nephropinae Dana, 1852, pp. 51–86 in Holthuis (1991).
  4. ^ Sammy De Grave, N. Dean Pentcheff, Shane T. Ahyong et al. (2009). "A classification of living and fossil genera of decapod crustaceans". Raffles Bulletin of Zoology Suppl. 21: 1–109. http://rmbr.nus.edu.sg/rbz/biblio/s21/s21rbz1-109.pdf. 
  5. ^ a b 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. 
  6. ^ "Key to species of the genus Homarus". p. 57. http://ip30.eti.uva.nl/bis/lobsters.php?menuentry=tekstsleutel&pagenum=12.  In Holthuis (1991).
  7. ^ a b c "Homarus gammarus". p. 60. http://nlbif.eti.uva.nl/bis/lobsters.php?menuentry=soorten&id=89.  In Holthuis (1991).
  8. ^ 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. http://books.google.co.uk/books?id=hFhjGhkAqZ0C&pg=PA188. 
  9. ^ T. W. Beard & D. McGregor (2004). "Storage and care of live lobsters" (PDF). Laboratory Leaflet Number 66 (Revised). Lowestoft: Centre for Environment, Fisheries and Aquaculture Science. http://www.cefas.co.uk/publications/lableaflets/lableaflet66rev.pdf. 
  10. ^ "Fishery Statistical Collections. Global Production". Fisheries Global Information System. Food and Agriculture Organization. http://www.fao.org/fishery/statistics/global-production/en. Retrieved September 30, 2010. 
  11. ^ 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. http://www.nobanis.org/files/factsheets/homarus_americanus.pdf. Retrieved May 4, 2011. 
  12. ^ "Heaviest marine crustacean". Guinness World Records. Archived from the original on May 28, 2006. http://web.archive.org/web/20060528192250/http://www.guinnessworldrecords.com/content_pages/record.asp?recordid=51451. Retrieved August 3, 2006. 
  13. ^ "Homarus americanus". p. 58. http://nlbif.eti.uva.nl/bis/lobsters.php?menuentry=soorten&id=87.  In Holthuis (1991).
  14. ^ a b 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. 
  15. ^ Carrie E. Schweitzer, Rodney M. Feldmann, Alessandro Garassino, Hiroaki Karasawa & Günter Schweigert (2010). Systematic List of Fossil Decapod Crustacean Species. Crustaceana monographs. 10. Brill. ISBN 978-90-04-17891-5. 
  16. ^ S. Polkowsky (2004). "Decapode Krebse aus dem oberoligozänem Sternberger Gestein von Kobrow (Mecklenburg)". Tassados (Schwerin: privately published) 1: 1–126. 

Bibliography