Malacostraca

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Malacostraca

• Shrimp, euphausiids, mysids

Pandalus danae Dock or Coonstripe Shrimp
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• Largest class of crustaceans
• Head in six segments
• Antennules, antennae, mouthparts
• Often have 8 thoracic legs
• First pairs can be modified into maxilipeds or
  pincers
• 8 thoracic segments, partially covered by
  cephalothorax
• 6 abdominal segments, can be used for swimming
• Eyes
• Two chambered stomach
• Centralized nervous system

http//en.wikipedia.org/wiki/Malacostraca
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http//en.wikipedia.org/wiki/Malacostraca
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Nauplius
3 pairs of appendages
Eye
Photo Wikipedia Characteristics Life, the
Science of Biology
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Zoea
Eye
Photo Wikipedia
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Oceanography in the 21st century, an online
textbook http//oceanworld.tamu.edu/resources/ocea
nography-book/contents.htm
TJ Smayda, 1969
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Euphausiacea

• Commonly called krill
• Carnivores, omnivores, herbivores
• 1-10cm in length (juvenile and adult)
• Of immense ecological significance
• Antarctic krill a keystone species, perhaps 2x108
  metric tons

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Meganyctiphanes norvegica or Northern
Krill http//en.wikipedia.org/wiki/FileMeganyctip
hanes_norvegica2.jpg
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http//www.classroomatsea.net/JR161/pics/foodweb.j
pg
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Laws, 1977
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• Krill and fish swarm off WA coast
• Krill swarm

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Shrimp (Decapoda)

• Primarily marine, but some aquatic
• Wide habitat range
• Economically important zooplankton
• 2.8 million tons produced yearly in mariculture
  (www.shrimpnews.com)
• Total harvest exceeds 3.42 million tons

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Primavera, 2005 See also Thu and Populus, 2007
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http//www.whoi.edu/cms/images/lstokey/2005/1/v41n
2-white2en_5088.jpg
http//people.whitman.edu/yancey/ventshrimp.jpg
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Mysids (within superorder Peracarida)

• Primarily marine but some aquatic (72 species,
  but 3 of 4 families)
• Aquatic includes subterranean species and other
  relics
• Similar in appearance to shrimp
• Roughly 1.5 cm in length as adult
• Larger species in mesopelagic
• Carry young in pouch until motile
• Important detrital feeders

Whittman, 1998 Porter, 2007 Miller, 2004
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Neognathophausia ingens (Deep water giant red
mysid)
http//www.wallawalla.edu/academics/departments/bi
ology/rosario/inverts/Arthropoda/Crustacea/Malacos
traca/Eumalacostraca/Peracarida/Lophogastrida/Neog
nathophausia_ingens.html