1. Most widespread and abundant phylum of animals
ARTHROPODS
Most widespread and abundant phylum of animals
3 out of 4 animals are arthropods!

2. Classification
Two major subphylums that marine arthropods are found in
Subphylum CRUSTACEA
Suphlyum CHELICERATA

3. GENERAL CHARACTERISTICS
Exoskeleton made of chitin
Segmented body
Specialized appendages
Sensory, feeding, movement
Mandible- Special mouthparts in arthropods for chewing food
Can regenerate appendages
Gills to obtain oxygen from sea water

4. Well developed organ systems Open CS Well developed NS Complete DT
GENERAL CHARACTERISTICS cont…
Well developed organ systems
Open CS
Well developed NS
Complete DT
Reproduction-separate sexes and sperm is usually directly transferred to the female

5. Arthropods molt-shed their shell & grow a new one as they grow.

6. Crustaceans Largest marine group
Biramous appendages- legs branch off into 2 parts

8. The swimming legs of crustaceans are called swimmerets.

9. Crustacean Habitats
Mostly a marine group
Insects of the sea
Important members of benthic
communities
dark nooks (under rocks and crevices)

10. Detritivores (scavengers) Parasites Carnivorous
CRUSTACEAN FEEDING
Detritivores (scavengers)
Parasites
Carnivorous

11. Maxillipeds- special appendages in crustaceans (arms)for cutting and manipulating food

12. Serial homology of appendages as seen in a stomatopod
Serial homology of appendages as seen in a stomatopod. From left to right appendages are: antennule, antenna, mandible, first and second maxillae, first through fifth maxillipeds, 3 walking legs, 5 pleopods with pinkish gills, and uropod.

13. CLASS MAXILLIPODA
SMALL CRUSTACEANS like:

14. -may be the most common animal
Copepods
-may be the most common animal
-important as zooplankton
and food source for larger consumers

15. Parasitic copepod in mako gills

16. Many copepods are parasites of fish.

17. usually attached to surfaces (very particular about where they attach)
Barnacles
filter feeders
usually attached to surfaces (very particular about where they attach)

18. Class Malacostraca
Larger crustaceans like…..

19. Krill Swarming, shrimp like animals found in all oceans
Important in polar waters as food source for whales, penguins, seals
Declines in krill populations are a concern for food web
Linked to melting sea ice
Linked to commercial krill fishery

20. Most diverse and widespread small crustacean
Order Amphipoda
Tiny and shrimp-like
Most diverse and widespread small crustacean
Found in almost all damp environments
Some are parasitic

21. Found on ocean floor from shallow to deep ocean
Isopods
flat from top to bottom
Found on ocean floor from shallow to deep ocean

23. 1st pair of legs for defense and getting food
Decapods
1st pair of legs for defense and getting food
Well developed carapace (outer shell)
Can feel pain

24. compound eyes on stalks well developed sense of smell scavengers
Lobsters
large front claws
-walking decapod
compound eyes on stalks
well developed sense of smell
scavengers

26. Lobsters may live to be 100 years old.

27. Female lobster holds eggs in her swimmerets.

28. Shrimp Diverse group of crustaceans Found in salt and freshwater
Important food source for humans and marine life

29. Shrimp are scavengers that feed on small pieces of dead plant and animal material (omnivores).
stilton.tnw.utwente.nl/shrimp/shrimp1.jpg

30. CRABS
Small abdomen that is tucked under thorax
Most scavengers
Live along rocky shoreline
Some terrestrial (return to sea only to release eggs)

31. Mouth
Swimming legs

32. Female crab holds eggs in her abdomen.

33. The 2 grasping claws of crabs are also called pincers or chelipeds.

34. Wider abdomen is female
Sexing crabs
Narrow abdomen is male
Wider abdomen is female

35. Class Merostomata horseshoe crabs Book gills for breathing
Mouth parts for piercing called chelicerae
living fossil

36. Blood is used to test for bacteria in pharmaceuticals
Critical food source for migrating shore birds like the red knot
Conservation efforts to ban use of crab meat as bait

37. Pycnogonida Found worldwide Most are small and deep water
Use a "proboscis " to pierce and suck liquid from seaweeds and various invertebrates.

38. The Japanese spider crab is the largest arthropod

39. Fiddler Crabs