Marb 435 1st Edition Lecture 19Current Lecture: Arthropoda 3Superclass Crustacea About 42,000 described species Huge diversity of body plans Primarily marine, some freshwater taxa and a few terrestrial ones (wood lice, crabs, hermit crabs) Commercially and ecologically important link between primary producers (phytoplankton) and higher level consumers (fishes) Taste good!Superclass Crustacea Class Malacostraca Order Isopoda (e.g. wood lice, pill bugs, Ligia) Order Amphipoda Order Euphausiacea (krill) Order Stomatopoda (mantis shrimps) Order Decapoda (crabs, lobsters, shrimp, crayfish) Class copepoda Class cirripedia (barnacles)Head appendages• 2 pairs of antennaeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.• 1 pair of mandibles• 2 pairs of maxillaeNauplius LarvaThere are many different larval types in crustaceans, but the nauplius is the basic oneCharacteristic Features:• Central eye (naupliar eye)• Has only the first three segments and their appendagesSubclass Malacostraca Contains ~ 60% of all crustacean species Always 19 segments Tagmata: head,thorax and abdomen Head and thorax often fuse to form a cephalothorax which may be covered by a carapaceOrder Isopoda About 4,000 species Mostly marine, but also in freshwater and terrestrial habitats (wood lice, pill bugs) Some parasitic groups Exclusively benthic Mostly dorsoventrally flattenedCymothoaexigua is parasitic in fishCauses degeneration of and functionally replaces the tongueOrder Amphipoda Mostly marine, but also some freshwater and terrestrial species Pelagic or benthic Shrimp-like body Mostly 5-15 mm long Can occur in very high densitiesOrder Euphausiacea Pelagic Shrimp-like body Most species are bioluminescent Have eyelike photoreceptors at the bases of their legs in addition to the stalked compound eyes Harvested as fish food and for human consumptionAntarctic Krill Fisheries Krill form huge swarms with up to 30,000 individuals per cubic meter Sustains populations of penguins, whales and seals New fishing technologies have doubled the annual catch over the last century Commercial fisheries currently dominated by Korean and Norwegian companies Fishing quotas are in placeOrder Stomatopoda (Mantis Shrimps) Range from 5 to 36 cm Often very colorful Predators of fishes, crabs, shrimps and molluscs Large raptorial claws that deliver the fastest punch in the animal kingdom (23m/s); usingcavitation force Use fluorescence to communicate with each otherStomatopod Eyes Eyestalks move independently of each other Each eye consists of upper and lower hemisphere and midband trinocular vision and depth perception in a single eye Midband is responsible for color vision At least eight photopigments for color vision and three for polarized light The first animal shown to detect circularly polarized light!Family Alpheidae• A.k.a. snapping shrimp or pistol shrimp• Have an oversized claw• When the claw is shut, a jet of water is produced that shoots out at 100 km/hr and leaves a small bubble in its wake• Bursting bubble stuns prey • The bubble also emits a flash of light due to high pressure and temperature (shrimpoluminescense!)Lobster-like Decapods Dorsoventrally flattened Large, shrimp-like abdomen Move with their pereopods but can rapidly escape backwards by flexing their abdomen and tail fin ventrally Usually with large chelipeds (claws)Family Panuliridae No enlarged chelipeds Caribbean spiny lobster (Panulirusargus) occurs in the tropical and subtropical Atlantic, Caribbean and Gulf of Mexico Inhabits protected crevices and caverns in coral reefs and other hard-bottom environments Known to migrate into deeper waters during the stormy season The only known invertebrate with true navigation based on the Earth’s magnetic fieldFamily Cambaridae Freshwater crayfish without pelagic larval stage Live in bodies of freshwater that do not freeze to the bottom Popular as food in many parts of the world Some live buried in the groundFamily Coenobitidae Terrestrial hermit crabs  Live relatively close to the shore and use freshwater or seawater to keep their respiratory surfaces moist Reduced gills, have lungs for gas exchange The coconut crabBirguslatro has given up the shell Can dehusk and open coconut shellsFamily Lithodidae More closely related to hermit crabs than to other crabs (Brachyura) Primarily in cold waters Three commercially fished species in Alaska: Red king crab (Paralithodescamtschaticus) Blue king crab (Paralithodes platypus) Golden king crab (Lithodesaequispinus)Family Portunidae Last pair of legs transformed into paddles Primarily benthic but can swim forward, backward and sideways The blue crab (Callinectessapidus) is very common in GoM “Soft-shell crabs”: recently molted blue crabs whose cuticle has not yet mineralizedFamily Cancridae Dungeness crab (Cancer magister) most important commercial crab species on US and Canadian west coast, up to Aleutian islands Can reach up to 2 kg and carapace span of 23 cm  Often bury themselves completely in sandFamily Majidae Include decorator and spider crabs Decorator crabs:  “Decorate” themselves with encrusting organisms Remain inactive during the day when predators are active Spider crabs: The Japanese spider crab (Macrocheirakaemperi) can reach up to 3.8 m in leg