Oregonia (genus)

Oregonia
Temporal range: Oligocene–Recent
Oregonia gracilis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Infraorder: Brachyura
Family: Oregoniidae
Genus: Oregonia
Dana, 1851
Type species
Oregonia gracilis
Dana, 1851

Oregonia is a genus of crabs, comprising two extant species[1] and one fossil species:[2] It is classified under the family Oregoniidae under the spider crab superfamily Majoidea.[1]

Description

The members of the genus are characterized by subtriangular or suboblong carapaces moderately covered with small protrusions (tubercles). They have large spines on the rear margins of the eye orbits (the postorbital spine) that are situated quite far from the eyestalks. The male chelipeds are elongated. The palms (manus) of the claws are long, compressed, and widen on the outer ends. The walking legs (pereiopods) are slender and decrease in length regularly towards the back. The abdomen (pleon) has seven segments.[3][4]

Species

Three species are currently recognized under the genus:

The previously described species O. longimana, O. mutsuensis and O. hirta have all been subsumed into O. gracilis.[4][7] O. hirta in particular was misidentified as a separate species due to the sexual dimorphism exhibited by majoid crabs. They were actually the females of O. gracilis.[4]

See also

References

  1. 1 2 Peter Davie (2010). "Oregonia Dana, 1851". World Register of Marine Species. Retrieved January 11, 2012.
  2. 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.
  3. Mary J. Rathbun (1925). The Spider Crabs of America (PDF). Bulletin (United States National Museum) 129. Washington: Government Printing Office. pp. 71–79.
  4. 1 2 3 John S. Garth (1958). Brachyura of the Pacific Coast of America, Oxyrhyncha (PDF). Allan Hancock Pacific Expeditions. Volume 21, Part 1. Los Angeles: The University of Southern California Press. pp. 135141.
  5. Francisco J. Vega, Torrey G. Nyborg and María Del Carmen Perrilliat (2006). "Topics in Geobiology". Studies on Mexican Paleontology 24: 79–100. doi:10.1007/1-4020-3985-9_5. |chapter= ignored (help)
  6. Carrie E. Schweitzer, Rodney M. Feldmann, Gerardo González-Barba & Francisco J. Vega (2002). "New crabs from the Eocene and Oligocene of Baja California Sur, Mexico and an assessment of the evolutionary and paleogeographic implications of Mexican fossil decapods" (PDF). Journal of Paleontology 76 (6 (Suppl.)): 1–43. doi:10.1666/0022-3360(2002)76[1:ncftea]2.0.co;2.
  7. Masatsune Takeda (1987). "Oregonia mutsuensis Yokoya, 1928, as a synonym of O. gracilis Dana, 1851" (PDF). Zoology, National Science Museum, Tokyo 20: 133–136.

External links

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