1. Phylum Arthropoda “Jointed foot”
Contains at least 75% of the described, living species of animals
Almost 90% of the arthropods are insects
Marine, fresh water, terrestrial and airborne
Size range < 1mm mites to 4 m spider crabs

2. Phylum Arthropoda Exoskeleton (chitin) moult Jointed appendages
Body divided into 2 or 3 sections
Straight gut
Brain and ganglia
Open circulatory system
Dioecious

3. Phylum Arthropoda
Metameric segmentation
Tagmatizaion

4. Phylum Arthropoda Cirripeds Copepods Isopods Amphipods Decapods
Insects Crustaceans Spiders & Scorpions
Cirripeds Copepods Isopods Amphipods Decapods

5. Phylum Arthropoda Class Crustacea
52,000 described species, 10 to 100 times more undescribed
Most are free-living and marine
Two pairs of antennae
Biramous limbs
Nauplius larva

6. Phylum Arthropoda Class Crustacea Subclass Cirripedia
Barnacles
Classified as molluscs until 1830
First fully studied and classified by Charles Darwin
~ 1200 species
e.g. acorn barnacle Balanus sp

7. Phylum Arthropoda Class Crustacea Subclass Cirripedia
Barnacles are shrimp standing on their head (cemented to the substrate) and feeding with their feet (called cirri)

8. Phylum Arthropoda Class Crustacea Subclass Cirripedia
e.g. Goose neck barnacles Pollicipes sp
Barnacles do not
have a true heart
Do not have gills,
instead oxygen
diffuses through their cirri
Sensitive to touch and have a single eye

9. Phylum Arthropoda Class Crustacea Subclass Cirripedia
Most Barnacles are filter feeders and use the water currents for their feeding advantage.

10. Phylum Arthropoda Class Crustacea Subclass Cirripedia

11. Phylum Arthropoda Class Crustacea Subclass Cirripedia
Barnacles are sessile
free living but some are
parasitic
(Rhizocephalans).
Decapod host
Only the larval form
resembles that of barnacles
the adults lack appendages and internal organs except for gonads

12. Phylum Arthropoda Class Crustacea Subclass Copepodia
13,000 described species and half are parasitic
they form the largest animal biomass on earth
Main contributor to secondary productivity and the carbon sink of the world oceans

13. Phylum Arthropoda Class Crustacea Subclass Copepodia
Very small (1-2 mm)
Mostly marine / planktonic
Thin transparent cuticle
One compound eye (red)
No heart
Lack gills (oxygen diffuses thru the cuticle)
Abdomen has no appendages

14. Phylum Arthropoda Class Crustacea Subclass Copepodia
Tide pool copepods e.g. Tigriopus sp
Can survive freezing, high temperatures, desiccation and extreme salinity changes

15. Phylum Arthropoda Class Crustacea Subclass Copepodia
Copepods have bristle-like setae that act as mechanorecptors.
An array of such sensors allows detection of patterns of water flow around the body caused by approaching prey or predator, and the copepod can distinguish between the two.

16. Phylum Arthropoda Class Crustacea Subclass Copepodia
Copepods are dioecious
Planktonic copepods use pheromones emitted by the swimming female, which leaves a trail in the water that the male can follow to locate the female

17. Phylum Arthropoda Class Crustacea Subclass Copepodia
During mating
Male grips the female with his antennae, The male then transfers sperm to the female. Eggs are sometimes laid directly into the water, but many species enclose them within a sac attached to female's body until they hatch.

18. Phylum Arthropoda Class Crustacea Subclass Copepodia
Eggs hatch into a nauplius larvae
The nauplius moults 5 or 6 times, before emerging as a "copepodid larva".
After a further five moults, the copepod finally takes on the adult form.
Egg to adult can take one week or one year depending on species

19. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Isopoda
Mostly free-living marine e.g. Idotea sp
Crawl rather than swim
Terrestrial – pill bug
Some parasitic (fish, shrimp and crab hosts)
Biphasic molt
Carapace – cephalic shield

20. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Isopoda - Elongated flat and somewhat arched bodies

21. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Isopoda
Females are brooders
After female moults males deposit sperm into the brood pouch
Eggs pass from the oviduct into the pouch and are fertilized on the way
Isopods hatch from the eggs as manca (adult like but last pair of walking legs are missing). Become juveniles 3 moults later

22. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Isopoda
No free-swimming larval stage
Endemism
Dispersal limited to the crawling ability of the individual

23. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Isopoda
Excirolana vancouverensis
Consume 53% of body mass in 1 minute

24. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
c-shaped bodies flattened laterally
Free living mostly marine and freshwater
Swim or hop
Do not have a carapace

25. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda

26. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
Females have a brood pouch
Hatch as miniature adults
Development varies with temperature
For some, gender varies with temperature (cold = male, warm = female)

27. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
Amplexus – large males grasp onto females with their gnathopods and carry them for several days
Females moult before they shed their eggs and are vulnerable to predation

28. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
Females secrete a pheromone in her urine which triggers the guarding behaviour in males plus they lose the desire to eat them
After her eggs are fertilized her exoskeleton hardens and the male is encouraged to leave

29. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
Amphipods are difficult to identify, due to their small size, and the fact that they must be dissected. As a result, ecological studies and environmental surveys often lump all amphipods together
Around 7,000 species of amphipods have so far been described

30. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
Most planktonic species are symbionts with gelatinous animals sometime during
their lifecycle.

31. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
Few are parasitic
The whale lice - these are dorso-ventrally flattened, and have large, strong claws, with which they attach themselves to baleen whales. They are the only parasitic crustaceans which cannot swim during any part of their lifecycle

32. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Amphipoda
Caprellids
Skeleton Shrimp.
their body shape and
colour help them blend
with their surroundings and the gentle back and forth sway resembles substrate within the water current.

33. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
15,000 species, half of these are crabs, ¼ are shrimp and the other ¼ are anomurans
Most are marine but some are freshwater and a few are terrestrial

34. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Deca = ten, pod = foot
Appendages
5 pairs on the thoracic segment, 1st usually a claw
Three pairs, maxillipeds (mouth parts)
Each abdomen segment has a pair of pleopods
Tail fan telson and uropod

35. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
anatomy

36. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda

37. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda

38. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Shrimp vs Prawn
Lamellar gill vs branched
Two pairs of claws vs three
Brood eggs before hatching vs doesn’t brood

39. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Shrimp
Prawna

40. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Caridia
Shrimps
Adapted for swimming
Bodies are laterally compressed
Slender legs and well developed swimmerets (pleopods)
Rostrum
Compound eyes

41. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Coonstripe or Dock Shrimp (Pandalus danae)

42. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Humpback or King Shrimp (Pandalus hypsinotus)

43. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Smooth or Ocean Pink Shrimp (Pandalus jordani)

44. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Pink Shrimp - Spiny (Pandalus borealis)

45. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Prawn or Spot Shrimp (Pandalus platyceros)

46. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Sidestripe or Giant Shrimp (Pandalopsis dispar)

47. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Caridia
Heptacarpus sp.
Intertidal shrimps
Transparent or a variety of colours
Hide during the day, feed and are easily seen at night.

48. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Caridia
Life cycle
Spend 1st years as males then switch to females.
Females brood their eggs (50,000 – 1 million)

49. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Caridia
Life cycle
Eggs hatch nauplii larvae (yolk sac)
metamorphosis into zoeae (feed on algae)
Metamorphisis into myses (feed on algae and zooplankton
Metamorphosis into young shrimp

50. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Caridia
Amazing shrimps
The pistol shrimp
The mantis shrimp

51. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Anomura
Differently tailed
Have 5 pairs of periopods but 1 pair is internal and used to keep their gills clean
If you see a crab with four legs then it is an anomuran.

52. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Anomura
Squat Lobsters
The body is usually flattened
the abdomen is typically folded under itself
the first periopods are greatly elongated and armed with long chelae (claws).

53. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Anomura
Porcelain crab
less than 15 mm (0.6 in) wide
flattened bodies as an adaptation for living in rock crevices
readily lose limbs when attacked
use their large claws for maintaining territories
They feed by using long setae (feathery hair on the mouthparts

54. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Anomura
Heart crab
Related to the Alaskan king crab
the asymmetry of the crab's abdomen, which is thought to reflect the asymmetry of hermit crabs, which must fit into a spiral shell (pleopods are smaller on one side)

55. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Anomura
Hermit crabs
Live in gastropod shells usually.
Spirally coiled soft abdodmen
Pleopod assymetry
tip of abdomen is adapted to clasp onto the columella of the shell.

56. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Anomura
Hermit crabs
vacancy chains: when a new, bigger shell becomes available, hermit crabs gather around it and form a queue from largest to smallest. When the largest crab moves into the new shell, the second biggest crab moves into the newly vacated shell and so on.

57. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Anomura
Hermit crabs
Symbiosis:
with the sponge
With anemones

58. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Brachyura
True crabs
Eg. Hemigrapsus sp
reduced abdomen is entirely hidden under the thorax
Telson not functional, uropods are absent

59. Phylum Arthropoda Class Crustacea Subclass Malacostraca
Order Decapoda
Infraorder Brachyura
True crabs
New research suggests that crabs not only suffer pain but that they retain a memory of it.

60. Pycnogonid – sea spider
Body not divided into distinct regions
Very slow moving
Appendages at the head which are used to groom the opposite sex’s legs and are used by the males to carry fertilized eggs