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Phylum Arthropoda, Subphylum Crustacea
• The majority of marine arthropods are crustaceans (subphylum Crustacea)
• Crustaceans are distinguished from other Arthropods by their possession of a pair of biramous (two-parted) limbs, and by a nauplius larval stage– Includes barnacles, shrimp,
krill, crabs, lobsters, and copepods
http://www.earthlife.net/inverts/crustacea.html
Phylum Arthropoda, Subphylum Crustacea
• Crustaceans are specialized for life in the water– Most possess gills to obtain oxygen– Chitinous exoskeleton reinforced with CaCO3
– Two pairs of antennae
The wonderful world of crustaceans!
Amphipods have a curved body that is flattened sideways
Isopods are dorsoventrally flattened
Shrimps, lobsters and crabs are decapods; all have ten legs made up of 5 pairs of appendages
12-5
Molting
• Arthropods must molt, or shed, their exoskeleton as they grow
• Most arthropods are small because the rigid exoskeleton puts limitations on their size
serc.si.eduhttp://movingspaceproductions.com/view.php?video=Daz8nkh-pWM&feature=youtube_gdata_player&title=Molting+horseshoe+crab
serc.si.eduafcd.gov.hk
Other Marine Arthropods
• Other than crustaceans, there are relatively few marine Arthropods
• Horseshoe crabs are not crustaceans, and belong to subphylum Chelicerata– Largely extinct; only five living species– Horseshoe-shaped carapace* that encloses a body
with six pairs of legs*shield-like structure that covers anterior portion of
Arthropods