Decapods (& a little of the Isopods)

Question 1

Arthropoda is a super phylum made of 3 subphylum. Name them.

Answer 1

Chelicerata,
Uniramia,
Crustacea

Question 2

Chelicerata is a subphylum made of 3 classes. Name them.

Answer 2

Merostomata (horse shoe crabs),
Arachnida (spiders, scorpions),
Pycnogona (sea spiders)

Question 3

Uniramia is a subphylum made of 2 classes. Name them.

Answer 3

Myriapoda (centipedes, millipedes),

Hexapoda (insects)

Question 4

Crustacea is a subphylum made of 9 classes. Name them.

Answer 4

Cephalocarida (detritivores, discovered 1955),
Branchiopoda (water fleas, shrimps),
Remipedia (cave spp. discovered 1980),
Mystacocarida (meiobenthic),
Branchiura (parasitic fish lice),
Copepoda (copepods),
Cirripedia (barnacles),
Ostracoda (ostracods),
Malacostraca (shrimps, lobsters, crabs)

Question 5

Malacostraca is a class that is composed of 3 subclasses. Name them.

Answer 5

Phyllocarida,
Hoplocarida,
Eumalacostraca.

Question 6

Phyllocarida has 1 order. What is it?

Answer 6

Leptostraca (sea fleas)

Question 7

Hoplocarida has 1 order. What is it?

Answer 7

Stomatopoda (mantis shrimps)

Question 8

Eumalacostraca is made up of 3 superorders. What are they?

Answer 8

Syncarida,
Peracarida,
Eucarida

Question 9

Syncarida has 2 orders. What are they?

Answer 9

Bathynellacea,

Anaspidacea

Question 10

Peracarida has 9 order. What are they?

Answer 10

Spelaeogriphacea,
Thermobasenacea,
Lophogastrida,
Mysida,
Mitacea,
Amphipoda,
Isopoda,
Tanaidacea,
Cumacea

Question 11

Eucarida has 3 order. What are they?

Answer 11

Euphausiacea,
Amphionidacea,
Decapoda

Question 12

What is the largest grouping in Malacostraca? What does it include?

Answer 12

Decapoda;

includes crabs, shrimps, crayfish and lobsters

Question 13

Thoracic segments fused to form a carapace (branchial chamber) is called the ____________.

Answer 13

Cephalothorax

Question 14

What is the pleon?

Answer 14

the abdomen

Question 15

Maxillipeds are found where?

Answer 15

Thoracic I - III

Question 16

What is found at Thoracic IV - VIII? How many are there?

Answer 16

Pereopods;

5

Question 17

There are 6 pleopods. What are they called?

Answer 17

Pleopods 1 - 5 are called “Swimmerets”;

Pleopod 6 is called the Uropod

Question 18

From egg to adult crab, what are the stages of a generalised crab life cycle?

Answer 18

Egg;
Zoea;
Megalopa;
Juvenile Crab;
Adult Crab

Question 19

From egg to adult, what are the stages of a generalised shrimp life cycle?

Answer 19

Egg;
Nauplius;
Protozoea;
Mysis;
Postlarval stage;
Adult

Question 20

Where can species of the order Isopoda be found?

Answer 20

Terrestrial, marine and freshwater environments

Question 21

Where do Isopoda females carry young?

Answer 21

in a pouch

Question 22

Few marine species are fish parasites. Give a named example of one.

Answer 22

Ceratothoa imbricate

Question 23

What is biphasic moulting?

Answer 23

The back part of the body is cast off before the anterior part.

Question 24

What are the 3 hypothesis explaining global diversity patterns in freshwater crabs? Briefly describe.

Answer 24

1. Polyphyletic - crabs originated from a number of marine ancestors. Morphological similarities - convergence, NOT common ancestry.;
2. Archaic - Single Gondwanan origin with today’s distribution is the result of the breaking up of the supercontinent. Morphological similarities - common ancestry.;
3. Phylogenetic - Colonisation of freshwater from a SINGLE marine ancestor. Morphological similarities - post-gondwanan - common ancestry.

Question 25

How can global diversity patterns be explained?

Answer 25

Multiple colonisations from different marine ancestors;
OR;
Single colonisation prior to the Gondwanan break up

Question 26

Name at least 3 habitats that freshwater crabs can be found in.

Answer 26

Rivers;
Streams;
Waterfalls;
Wetlands;
Karsts;
Caves

Many species are semi-terrestrial

Question 27

What do freshwater crabs require?

Answer 27

Excellent water quality.

Sensitive to O2 levels;
heavy metals;
organic pollution etc.