Crustacea 2

Question 1

Classes

Cephalocarida

Remipedia

Mystacocarida

Branchiura

Copepoda

Tantulocarida

Cirripedia

Ostracoda

Malacostraca

Answer 1

..

Question 2

Class Branchiopoda

4 points

Answer 2

1. Most live freshwater and brackish water but some adapted to marine environments
2. 1,000 described species in 4 Orders
3. Number of segments and appendages on thorax and abdomen vary
4. Carapace either present or absent

Order Anostraca
Order Notostraca
Order Diplostraca
Order Cladocera

Question 3

Class Cephalocarida

5 points

Answer 3

1. Primitive benthic marine detritivores
2. Ten described species in one order
3. Body comprised of cephalon, thorax and abdomen

Carapace absent

4. Hermaphrodites
5. Order Brachypoda
   Elongated and cylindrical

Question 4

Class Remipedia

Answer 4

1. Primitive vermiform and cave-dwelling
2. Twelve described species in one order
3. Body comprised of cephalothorax and thorax

Carapace absent

4. Swim on back
5. Order Nectipoda
   Elongated and translucent

Question 5

Class Mystacocarida

5 points

Answer 5

1. Interstitial in littoral and sublittoral sands
2. Thirteen described species in one order
3. Body comprised of cephalon and thorax
   Carapace absent
4. Lateral, toothed grooves
5. Order Derocheliocarida

Feed by scrapping organic
material from sand surface

Question 6

Class Branchiura

Answer 6

1. Ectoparasites on marine and freshwater fishes
2. 150 described species in one order
3. Body comprised of cephalothorax, thorax and abdomen

Broad carapace

4. Modified mouthparts
5. Order Arguloida

Eggs attached to substrate

Question 7

Class Copepoda

4 points

Answer 7

1. Dominant in marine plankton
2. 8,000 - 12,000 described species in 10 orders
3. Body comprised of cephalothorax, thorax and abdomen

Carapace absent

4. Frequently encountered free-living copepods:

Order Calanoida
Order Harpacticoida
Order Cyclopoida

Question 8

Class Copepoda
Order Calanoida
3 points

Answer 8

1. Planktonic primary consumers
2. Narrowing of body between thorax and abdomen
3. Biramous, elongated antennules

Question 9

Class Copepoda
Order Harpacticoida
3 points

Answer 9

1. Benthic detritus feeders
2. Vermiform; posterior segments not much narrower than anterior
3. Biramous, short antennules and antennae

Question 10

Class Copepoda
Order Cyclopoida
3 points

Answer 10

1. Planktonic in marine and freshwater environments
2. Abrupt narrowing between fifth and six thoracic segments
3. Uniramous short antennules and moderately long antennae

Question 11

Class Tantulocardia

5 points

Answer 11

1. Ectoparasites on deep sea crustaceans
2. Twelve described species in one order
3. Body comprised of cephalon, thorax and abdomen
4. Highly modified adults
5. Order Tantulocaridia

Lack almost all diagnostic features

Question 12

Class Cirripedia 5 points

Answer 12

1. Adults sessile or parasitic
2. 1,200 described species in five orders
3. Body comprised of thorax and reduced abdomen

Carapace present in cyprids

4. Hermaphrodites
5. Frequently encountered cirripedes:
   Order Thoracica
   Order Ascothoracica

Question 13

Class Cirripedia
Order Thoracica
3 points

Answer 13

1. Modified thoracic legs (cirri)
2. Carapace reinforced with calcareous plates
3. Attachment by antennules

Question 14

Class Cirripedia
Order Ascothoracica
3 points

Answer 14

1. Parasites on cnidarians and echinoderms
2. Rudimentary head with antennules
3. Bivalved carapace

Question 15

Class Ostracoda

4 points

Answer 15

1. Small, bivalved calcareous carapace
2. 5,700 described species in five orders
3. Body comprised of cephalon and undivided trunk
4. Frequently encountered ostracods:

Order Myodocopa
Exclusively marine, both benthic and planktonic
Range of feeding strategies

Order Podocopa
Benthic
Range of feeding strategies

Question 16

Class Malacostraca

4 points

Answer 16

1. Largest class with greatest diversity of form
2. 23,000 described species in 16 orders
3. Body comprised of cephalon, thorax and abdomen
4. Frequently encountered malacostracans:
   Order Isopoda
   Order Amphipoda
   Order Decapoda

Question 17

Class Malacostraca
Order Isopoda
3 points

Answer 17

1. Marine, freshwater and terrestrial - common in all environments
2. Dorsally flattened, carapace absent, pereopods uniramous, pleopods biramous, sessile eyes
3. Suborder Oniscidea have successfully invaded terrestrial habitats
   Aerial gas exchange organs
   Thickened cuticle

Question 18

Class Malacostraca
Order Amphipoda
3 points

Answer 18

1. Marine, freshwater and terrestrial
2. Laterally flattened, carapace absent, modified perepods uniramous, pleopods biramous, sessile eyes

3. Suborder Gammaridea 
Mostly marine benthic species
Semi-terrestrial in moist forest leaf litter
Occur on sandy beaches
Subterranean groundwater ecosystems

Question 19

Class Malacostraca
Order Decopoda
6 points

Answer 19

1. Marine, freshwater and terrestrial
2. Body comprised of cephalothorax and abdomenn
3. Well-developed carapace enclosing branchial chamber
4. Three pairs of maxillipeds
5. Five-pairs of uniramous pereopods - one pair usually chelate
6. Reduced abdomen