Marb 435 1st Edition Lecture 19 Current Lecture Arthropoda 3 Superclass 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 antennae These 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 maxillae Nauplius Larva There are many different larval types in crustaceans but the nauplius is the basic one Characteristic Features Central eye naupliar eye Has only the first three segments and their appendages Subclass 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 carapace Order 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 flattened Cymothoaexigua is parasitic in fish Causes degeneration of and functionally replaces the tongue Order 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 densities Order 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 consumption Antarctic 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 place Order 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 using cavitation force Use fluorescence to communicate with each other Stomatopod 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 field Family 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 ground Family 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 shells Family 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 mineralized Family 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 sand Family 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 span