Crustaceans

Question 1

describe the segmentation of a crustacean

Answer 1

head = 5 segments (1-5; 2 antennae, 3 mouthparts)
thorax = 8 segments (6-13; pereopods walking legs)
abdomen = 6 segments (14-19; pleopods swimming legs + uropods)

Question 2

what types of appendages can crustaceans have?

Answer 2

endopod = closer to midline
exopod = farther from midline

stenopodial = leg like appendage, long exopod and endopods
phyllopodial = leaf like appendage, round flat exopod and endopods

Question 3

what is the name of the larval stage shared by crustaceans?

Answer 3

nauplius

Question 4

what classes are within the crustacean group?

Answer 4

Malacostraca, Cirripedia, Branchiopoda, Ostracoda, Copepoda, Xenocarida

Question 5

what characteristics do the maxillopodans (Branchiopoda, Cirripedia, Copepoda) have?

Answer 5

<19 segments, no appendages on abdomen

Branchiopods = repeated phyllopodial appendages
Cirripedia = reduced abdomen
Copepoda = 3 tagmata

Question 6

what are some unique traits from Ostracoda?

Answer 6

• no abdomen
• 7 segments total (5 head, 2 thorax)
• mineralized carapace covering entirety of body
• pereognaths (last head segment becomes walking legs)

Question 7

what three orders are within Branchiopoda?

Answer 7

Anostraca (sea monkeys), Cladocera (Daphnia, Podon), Conchostraca

Question 8

what segmentation does Cladocera have?

Answer 8

• 1 pair of maxillipeds
• 2nd antennae used to swim
• 5-6 thoracic segments
• no abdomen

Question 9

what segmentation does Anostraca have?

Answer 9

• 2 pairs of maxillipeds
• 6 swimming thoracic segments
• 6 legless abdominal segments
• no carapace

Question 10

what segmentation does Conchostraca have?

Answer 10

• no maxillipeds
• dozens of segments
• 1st antennae = swimming
• large carapace

Question 11

what are three orders within Copepoda?

Answer 11

Calanoidea, Cyclopoidea, Harpactacoidea

Question 12

what orders are within Malacostraca?

Answer 12

“Eucarida” (true shrimps):
- Decapoda
- Euphauseiacea

“Peracarida” (false shrimps)
- Isopoda
- Amphipoda

“Hoplocarida” (armed shrimps)
- Stomatopoda

Question 13

why is Phyllocarida considered a basal lineage?

Answer 13

• no maxillipeds
• unfused cephalothorax
• 8 thoracopods = phyllopods
• 8 pleopods = stenopods

Question 14

what are the differences between Eucarida and Peracarida?

Answer 14

Eucarida has:
- carapace fused to thoracic segments
- stalked eyes
- no brood pouch