Chapter 19: Phylum Arthropoda, Subphylum: Crustacean, Class: Malacostraca

Question 1

This class contains the most ___ of crustaceans.

Answer 1

diversity

Question 2

The orders covered in zoology lecture were what?

Answer 2

Isopoda, Amphipoda, Euphausiacea, Decapoda

Question 3

Order Isopoda ?

• only true ___?
• also live in what forms?
• how are they flattened? Carapace yes or no? eyes?
• some are highly modified as what?
• describe development?
• ex of this order?
• what does the cuticle lack ? what kind of habitats must they live in?

Answer 3

• only true terrestrial crustaceans
• but also have marine and freshwater forms
• dorsoventrally flattened, lack a carapace, have sessile compound eyes.
• some are highly modified as parasites of fishes or crustaceans
• development typically is direct but may be metamorphic in parasitic forms.
  EX: snow bugs, pill bugs
• cuticle lacks protection of insect cuticle and they must live in moist habitats.

Question 4

Order Amphipoda?
- they resemble what other order ?
L> in what way(s)?
- how are they compressed?
- gills location?
- abdominal and thoracic limbs are grouped for what?
- Many are ___ others are ___ dwelling, ___ or ___.

Answer 4

-resemble Isopoda
L> such that they lack a carapace, have sessile compound eyes and one pair of maxillipeds.
- They are compressed laterally, and gills are in the thoracic region.
-Abdominal and thoracic limbs are grouped for jumping and swimming
- Many are marine others are beach dwelling, freshwater or parasitic.

Question 5

Order Euphausiacea?

• includes what organisms?
• carapace does not completely cover what?
• it lacks what? all limbs have what?
• most are ___ and have a pigment called___, which produces?
• major component of what organisms diets
• eggs hatch as ?
• development is?

Answer 5

• Includes important ocean plankton called krill.
• Carapace does not completely enclose the gills
• lacks maxillipeds and all limbs have exopods
• most are bioluminescent, with a light producing pigment called a photophore.
• major component of the diet for baleen whales and of many fishes.
• eggs hatch as nauplii
• development is direct

Question 6

Order Decapoda?

• have __ pairs of walking legs and __ pairs of maxillipeds(appendage modified for feeding).
• in crabs the first pair of walking legs form what?
• This order includes what organisms?
• Crabs possess a broader ___ and reduced ___ compared to crayfish or lobsters.

Answer 6

• have five pairs of walking legs and 3 pairs of maxillipeds.
• in crabs the first pair of walking legs form pincers.
• includes crabs, crayfish, lobsters, true shrimp
• crabs possess a broader cephalothorax and reduced abdomen compared to crayfish or lobsters.