Phylum Arthropoda class Crustacea

Largest phylum of animals w/ approx One million known species

Includes: insects, spiders, crabs Barnacles, shrimp, & lobsters

General characteristics Bilaterally symmetric Have jointed appendages (legs & mouth parts) Exoskeleton made of chitin and hardened by CaCO3 Grow by molting

Molting: Old exoskeleton is shed leaving the animal soft The animal brings in water to expand itself A new exoskeleton is secreted by specialized tissue

Exoskeleton provides protection, support, & flexibility Also imposes limitations to grow & size

Class: Crustacea 30,000 species primarily marine Gill-breathing segments Open circulatory system Specialized appendages for food gathering, walking, fighting, defense, etc. Start out life as a planktonic larvae Ex: lobsters, crayfish, shrimp, crabs, copepods, barnacles, etc. Giant King Crab = largest crustacean (~12ft) Heaviest is the lobsters (up to 48 lbs!!)

Have two pairs of antennae (one pair smaller than the other) Small, planktonic crustaceans include copepods, barnacles, isopods, krill

Barnacles Chitin exoskeleton & secretes CaCO 3 shell. Feathery feet for filter feeding plankton Some attach to docks or boats and a few on whales Must close up with an operculum during low tide to avoid desiccation (drying up).

Barnacles and Crabs gLGPCk&safety_mode=true&persist_safety_mode=1&safe=active gLGPCk&safety_mode=true&persist_safety_mode=1&safe=active Barnacle info HA9R4&safety_mode=true&persist_safety_mode=1&safe=active HA9R4&safety_mode=true&persist_safety_mode=1&safe=active Giant Crabs 4&safety_mode=true&persist_safety_mode=1&safe=active 4&safety_mode=true&persist_safety_mode=1&safe=active Horseshoe Crabs _safety_mode=1&safe=active _safety_mode=1&safe=active Molting horseshoe crab pWM&safety_mode=true&persist_safety_mode=1&safe=active pWM&safety_mode=true&persist_safety_mode=1&safe=active

Other larger crustaceans include shrimp, lobsters & crabs Considered decapods (5 pairs of legs) Body consists of cephalothorax (fused head & thorax) & abdomen

Crabs have a compact abdomen & a broad cephalothorax Abdomen usually tucked under

Male Female

Abdomen with eggs

Lobsters R=1&safety_mode=true&persist_safety_mode=1&safe=active R=1&safety_mode=true&persist_safety_mode=1&safe=active Slipper lobster rsist_safety_mode=1&safe=active rsist_safety_mode=1&safe=active Spiny Lobster rsist_safety_mode=1&safe=active rsist_safety_mode=1&safe=active Lobster Life Cycle: Safari Montage

Giant Spider Crab

King and Coconut Crabs