Sub-phylum Crustacea crabs, lobsters, shrimps, crayfish, barnacles, water fleas, fairy shrimps, copepods, isopods, & amphipods

Crustacean Diversity

General Features diversity (30,000 species) fresh water & marine; terrestrial sessile, commensal, & parasitic biramous appendages (2) pair of antennae (1) pair of mandibles (2) pair of maxillae gills (usually) tagmata (e.g. cephalothorax)

Form & Function: appendages: specialization feeding swimmerets, uropods, & chelipeds feeding filter feeders, scavengers, parasites, & predators respiration: diffusion & gills excretion/osmoregulation: green gland- excretes ammonia circulation: open w/ hemocoel

Reproduction mostly dioecious direct or indirect development planktonic larvae in many

Class Cirripedia barnacles sessile (adults); marine, filter feeders respiration via the integument; no heart

Barnacles

Class Copapoda “cyclops”

Class Branchiopoda brine shrimp, fairy shrimp, and water fleas characteristics: small size, filter feeders, gilled, & locomotory & zooplankton Orders: Cladocera, Notostraca, & Anostraca parthenogenesis Daphnia used indicators of water quality

Order Notostraca- tadpole shrimps nine species; one family generally inhabit ephemeral lakes (playas)

Order Anostraca- fairy shrimps fairy and brine shrimps (sea monkeys) often inhabit ephemeral pools

Class Ostracoda- seed shrimps 6,650 species 54 genera and 420 freshwater spp. fresh water, marine, & estuarine consume mostly algae and organic detritus

Class Malacostraca largest and most diverse class crabs, shrimps, crayfish, lobsters, isopods, etc. marine, fresh water, and terrestrial benthic; scavengers, predators

Order Isopoda pill bugs, sow bugs, or “rolley polly” aquatic and terrestrial forms Dorso-ventrally flattened body

Order Amphipoda sand fleas & scuds laterally compressed body marine & fresh water

Order Decapoda largest order- > 10,000 species; 100 families crabs, lobsters, shrimp, crayfish, and hermit crabs marine, fresh water, & terrestrial chelipeds- grasping appendage

Callinectes- blue crab

megalopa

Crayfish Morphology

Ecdysis (molting) the Y-organ in the head of crustaceans controls ecdysis