1. Marine Ecology, April 18, 2007 Invertebrates 3: Phylum Arthropoda

2. Major arthropod features  Body segementation/specialization of regions  Paired, jointed appendages  Exoskeleton Several non-living layers of cuticle, secreted by the epidermis  Contains chitin Cuticle also forms mouthpart structures, lining of digestive tract, eye lens, and wings.

3. Phylum Arthropoda Subphylum Crustacea features Two pair of antennae, followed by three pairs of mouthparts Compound eyes, sometimes on stalks Head and thorax often combined into a "cephalothorax“ Appendages  Biramous (double-branched) appendages Not apparent in many crustaceans Often have calcium carbonate in cuticle (“crustose”) Many have gills.  In common crustaceans, attached to base of legs, extend up into thorax.

4. Other concepts/terms Thoracic appendages often are walking legs or modified for food handling Abdominal appendages sometimes modified as "pleopods", broad swimming appendages. Very end of abdomen often formed by two types of structures; can see these clearly in shrimp.  Telson  Uropods

5. Order Amphipoda (Beach hopper)

6. Order Isopoda Idotea sp. Ligia pallasii

7. Order Decapoda Carapace completely covers head and thorax Eight pairs of thoracic appendages  3 as modified mouthparts (maxillopeds)  5 pairs as walking legs

8. Order Decapoda Pagurus sp. Petrolisthes cinctipes Pachychelis rudis *Add me to your list!

9. Shore crabs Pachygrapsus crassipes Hemigrapsus oregonensis Hemigrapsus nudus

10. Cancer sp. crabs C. antennarius C. productus C. magister C. oregonensis

11. Pugettia producta: kelp crab

12. Order Cirripedia: the barnacles Balanus sp. Chthamalus sp. Pollicipes polymerus