Intertidal organisms 3: Phylum Arthropoda Marine Ecology, April 25, 2007 Intertidal organisms 3: Phylum Arthropoda

Phylum Arthropoda 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 mouthparts, lining of digestive tract, eye lens, and wings.

Phylum Arthropoda Subphylum Crustacea features Two pairs of antennae; 3 pairs of mouthparts Compound eyes, sometimes on stalks Body regions: Head and thorax often  "cephalothorax“ Abdomen Thoracic appendages (always) Abdominal appendages (in some) Often have calcium carbonate in cuticle Many have gills Often attached to base of legs, extend into thorax.

Other concepts/terms Thoracic appendages: walking legs and/or food handling Abdominal appendages sometimes modified as "pleopods", broad swimming appendages. Very end of abdomen in many: Telson Uropods

Reproduction Mating varies: Brooding of eggs/young Males provide females with spermatophores Sperm storage occurs in some. Brooding of eggs/young Some with direct development Many with pelagic larvae female releases fertilized eggs or Females release larval forms

Order Amphipoda (Beachhopper)

Order Isopoda Idotea sp. Ligiapallasii

Order Decapoda Carapace covers head and thorax Eight pairs of thoracic appendages 3 pairs assist with food handling (maxillopeds) In addition to the three pairs of mouthparts 5 pairs as walking legs (includes chelipeds)

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

Shore crabs Hemigrapsus nudus Pachygrapsus crassipes Hemigrapsus oregonensis

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

Reproduction: Cancer spp.

Reproduction

Pugettia producta: shield-backed kelp crab

Order Cirripedia “Test”: barnacle’s calcareous plates Moveable valves allow opening, closing Test is in addition to exoskeleton Filter-feeds with thoracic appendages No abdomen Reduced head

Order Cirripedia: the barnacles Balanus, Semibalanus sp. Pollicipes polymerus Chthamalus sp.

Cirripedia: life cycle http://www.jst.go.jp/erato/project/fck_P/icons/grf1_1.jpg