ARTHROPODS

• Most widespread and abundant phylum of animals

• 3 out of 4 animals are arthropods!

Two major subphylums that marine arthropods are found in

Subphylum CRUSTACEA

Suphlyum CHELICERATA

Classification

CHARACTERISTICS

• Exoskeleton made of chitin

• Segmented body

• Appendages specialized –Sensory, feeding, movement

–Can regenerate appendages

• Gills to obtain oxygen from sea water

Well developed organ systems –Open CS–Well developed NS –Complete DT

• Reproduction-separate sexes and sperm is usually directly transferred to the female

GENERAL CHARACTERISTICS cont…

Crustaceans• Largest marine group

• Biramous appendages- legs branch off into 2 parts

www.obs-vlfr.fr/.../copepods_guide/help.html

http://1.bp.blogspot.com/_e-mPA_6ZQyg/RvXkxRqUXVI/AAAAAAAAECM/xZ4BQgLV00w/s400/crustaceans.gif

Crustaceans molt-shed their shell & grow a new one as they grow.

http://www.dnr.state.md.us/baygame/molt2.jpg

The swimming legs of crustaceans are called swimmerets.

http://www.glf.dfo-mpo.gc.ca/photos/images/white_lobster.jpg http://home.earthlink.net/~wweinkle/crabinternal2.jpg

Mostly a marine group

Insects of the sea

Important members of benthic communities

dark nooks (under rocks and crevices)

Crustacean Habitats

Detritivores (scavengers)

Parasites

Carnivorous

CRUSTACEAN FEEDING

Maxilopeds- special appendages (arms)for cutting and manipulating food

Mandible- Special mouthparts for chewing food

• http://images.google.com/imgres?imgurl=http://www.ucmp.berkeley.edu/arthropoda/crustacea/images/serial_appendages_sm.jpg&imgrefurl=http://www.ucmp.berkeley.edu/arthropoda/crustacea/appendages.html&usg=__iENbe_1_g_87lJzQN9pPDvBhj28=&h=200&w=500&sz=21&hl=en&start=7&tbnid=fl05qzSmOmxIPM:&tbnh=52&tbnw=130&prev=/images%3Fq%3Dmandible%2Bmaxilloped%2Bcrustacean%26gbv%3D2%26hl%3Den%26safe%3Dactive

Serial homology of appendages as seen in a stomatopod. From left to right appendages are: antennule, antenna, mandible, first and second maxillae, first through fifth maxillipeds, 3 walking legs, 5 pleopods with

pinkish gills, and uropod.

-may be the most common animal

-important as zooplankton

and food source for larger consumers

Copepods

http://mysciencefairproject.net/images/macrocyclops1_zexs.jpg

Parasitic copepod in mako gills

http://carlsafina.wordpress.com/2007/07/05/welcome-to-the-hotel-californshark-2/

Many copepods are parasites of fish.

http://www.darwinsgalapagos.com/animals/parasitic_copepod_sm.jpg

• filter feeders

• usually attached to surfaces (very particular about where they attach)

Barnacles

http://shiftingbaselines.org/blog/Barnacle.jpg

Tiny and shrimp-like

Most diverse and widespread small crustacean

Amphipods

http://www.reef-eden.net/Amphipod1.jpg

• flat from top to bottom

• successful on land too

Isopods

http://blogs.nature.com/news/thegreatbeyond/giantisopod.jpg http://oceanexplorer.noaa.gov/explorations/04etta/background/isopods/media/synidotea_laevidorsalis.html

• shrimp-like

• important in polar waters as food source for whales, penguins, seals

Krill

http://www.mar-eco.no/learning-zone/__data/page/93/Krill3.jpg

Decapods• 1st pair of legs for defense

and getting food

• Well developed carapace (outer shell)

• Can feel pain

http://www.flmnh.ufl.edu/fish/gallery/descript/alligatorgar/bluecrab.JPG

Lobsters -large front claws - 4 pairs of jointed walking legs-compound eyes on stalks

www.metro.co.uk

Lobsters may live to be 100 years old.

http://www.cryptomundo.com/cryptozoo-news/giant-crayfish/

Female lobster holds eggs in her swimmerets.

http://www.penobscoteast.org/images/lobster_eggs.jpg

www.helgoland-lobster.de/indexe.html

Shrimp•Diverse group of crustaceans•Found in salt and freshwater•Important food source for humans and marine life

http://www.dfw.state.or.us/MRP/shellfish/commercial/largeimages/shrimp_headroe_eggs_large_ODFW.jpg

Shrimp are scavengers that feed on small pieces of dead plant and animal material (omnivores).

stilton.tnw.utwente.nl/shrimp/shrimp1.jpg

CRABS

• Small abdomen that is tucked under thorax

• Most scavengers

• Live along rocky shoreline

• Some terrestrial (return to sea only to release eggs)

Swimming legs

Mouth

Female crab holds eggs in her abdomen.

http://cache.daylife.com/imageserve/00DRgZO7DQehn/610x.jpg

The 2 grasping claws of crabs are also called pincers or chelipeds.

http://www.animalwebguide.com/Fiddler-Crab-1.jpg

Narrow abdomen is maleWider abdomen is female

http://hawaii.gov/dlnr/dar/images/Samcrabs.jpg

Class Merostomata• horseshoe crabs• Book gills for breathing• Mouth parts for piercing called

chelicerae• living fossil

http://beachchairscientist.files.wordpress.com/2008/07/horseshoe-crab.jpghttp://horseshoe-crabs.com/horseshoe-crab-book-gills.html

• Blood is used to test for bacteria in pharmaceuticals

• Critical food source for migrating shore birds like the red knot–Conservation efforts to ban use of crab meat as bait

Pycnogonida• Found worldwide

• Most are small and deep water

• Use a "proboscis " to pierce and suck liquid from seaweeds and various invertebrates.

The Japanese spider crab is the largest arthropod

http://huynhwinsituation.files.wordpress.com/2009/03/japanese-spider-crab.jpg

Fiddler Crabs