Annelida 2

Question 1

Overview of classes

Cheatae, parapodia, and cephalic appendages

Polychaeta

Clitellata
Subclass: Oligochaeta
Subclass: Hirudinoidea

Answer 1

…

Question 2

Overview of class Polychaeta
3 points

Answer 2

1. Generally marine
2. Each body segment has a pair of fleshy protrusions called parapodia that bear many chaetae.
3. Highly variable in morphology and habitat type, >10,000 species

Question 3

Overview of class Clitellata
3 points

Answer 3

1. Clitellum – important for reproduction.
2. They comprise around 8,000 species.
3. No parapodia and their heads are less developed heads

Question 4

Chaetae

3 points

Answer 4

1. Bundles of chitinous cylinders bound by protein
2. Large degree of variation
   Species-specific
3. Used for locomotion

Question 5

Parapodia

4 points

Answer 5

1. Unjointed, fleshy appendages
2. Large degree of variation
   Species-specific
3. Two elements: notopodium and neuropodium
4. Used for locomotion and respiration

Question 6

Cephalic appendages

4 points

Answer 6

1. High diversity in cephalic appendages
2. Palps
   Grooved feeding palps
   Sensory
3. Tentacle structure varies
4. Provide information of feeding

Question 7

Class: Polychaeta [key points]

Answer 7

1. Segments bear chaetae (analogous to setae)
2. Well developed parapodia
3. Prostomium and peristomium bear pronounced sensory organs, and motile appendages
4. Modified foregut
5. Dioecious
   Indirect development
   Trochophore larva
6. Mostly marine
7. 87 families in 25 orders

Question 8

Class: Polychaeta
Order: Capitellidae; Family: Arenicolidae
7 points

Answer 8

1. Lug worms or black lugs
2. Thick fleshy bodies with simple heads
3. Pharynx is unarmed and eversible
4. Burrowers
5. Deposit feeders, some graze on algae
6. Interitadal and subtidal
7. Excellent indicator species for pollution

Question 9

Class: Polychaeta
Order: Phyllodocida
5points

Answer 9

1. 4,600 species in 20 Families
2. Variable size, can exceed 1 m
3. Axial muscular proboscis
4. Mostly errant with well-developed parapodia
5. Prostomium with one or two pairs of eyes, dorsal pair of antennae and a pair of ventrally positioned sensory palps.

Question 10

Class: Polychaeta
Order Phyllodocida; Family Nereididae
7 points

Answer 10

1. Ragworms
2. Burrowers in sand and mud
3. Bioturbators
4. Common in estuarine, coastal sites but also in deep sea
5. Predators or scavengers but also feed on algae and microorganisms
6. Numerous, highly vascularized parapodia
7. Well-developed heads with two large pincer teeth

Question 11

Class: Polychaeta
Order: Phyllodocida; Family Aphroditiformia
8 points

Answer 11

1. Scaled Polychaetes known as the “scale worms”
2. Short and dorsoventrally flattened
3. Can reach 30cm in length and 15cm width (Eulagisca gigantea)
4. Relatively few segments at adulthood.
5. Covered in scales called elytra
6. Can be active predators
7. Eversible pharynx
8. Commensal

Question 12

Class: Polychaeta
Order: Sabellida
8 points

Answer 12

1. 1200 species across 5 Families
2. Heteronomous body form
3. Huge size range from 3 to 2500 mm
4. Mostly sedentary
5. Tube-dwellers
6. Ecosystem engineers
7. Anterior end bears tentacular crown
8. Suspension feeders

Question 13

Class: Polychaeta
Order: Sabellida; Families: Sabillidae and Serpulidae
2 points

Answer 13

1. Sabellids 
Live in sediment
Mucus tubes
Radiolar crown or feathery palps
Suspension feeder

2. Serpulids
Calcareous tubes
Usually attach to rocks
Radiolar crown or feathery palps
Suspension feeder

Question 14

Class: Polychaeta
Order: Sabellida; Family: Siboglinidae
6 points

Answer 14

1. Sedentary
2. Chitin tubes
3. Biogenic structures
4. Host endosymbiotic bacteria
5. Lack a mouth, anus and gut
6. Chemosynthetic and organic rich habitats

Question 15

Class: Polychaeta
Order: Sabellida; Family: Siboglinidae; Genus: Osedax

4 points

Answer 15

1. Bone eating zombie worms
2. Found only on long-submerged bones
3. Between 50 and 100 microscopic dwarf males live inside a single female and never develop past the larval
4. Osedax have colourful feathery plumes that act as gills

Question 16

Class: Polychaeta
Order: Sabellida; Family: Siboglinidae; Genus: Osedax
3 points

Answer 16

1. Osedax symbiotic bacteria digest the whale proteins and lipids.
2. The Osedax secrete acid (rather than rely on teeth) to bore into bone to access the nutrients.
3. Unusual root-like structures that absorb nutrients.

Question 17

Class: Clitellata [key points]

6 points

Answer 17

1. Chaetae reduced or absent
2. No parapodia
3. Prostomium and peristomium often lack pronounced sensory organs
4. Clitellum
5. Hermaphroditic
   Complex reproductive system
   Direct development
6. Marine, freshwater and terrestrial environments

Question 18

Class: Clitellata
Sub-class: Oligochaeta
6 points

Answer 18

1. Over 6,000 species in three orders with 25 families
2. Chaetae reduced or absent
3. Cephalic structures reduced
4. Externally homonomous
5. Clitellum
6. Hermaphroditic

Question 19

Class: Clitellata
Sub-class: Oligochaeta
Order Crassiclitellata

Answer 19

1. Mainly terrestrial earthworms
2. Over 3000 species
3. Direct deposit feeders consuming live and dead organic matter
4. Clitellum

Question 20

Class: Clitellata

Sub-class: Oligochaeta

Order Haplotaxids

Family Naididae

5 points

Answer 20

1. Mainly freshwater but includes marine and brackish
2. 700 species
3. Tube builders or burrowers
4. Homonomous with a simple head
5. Some reproduce asexually

Question 21

Class: Clitellata

Sub-class: Oligochaeta

Order Haplotaxids

Family Enchytraeidae

3 points

Answer 21

1. Mainly terrestrial with ~700 species but also marine
2. Feed on bacteria, fungi and algae
3. Mesenchytraeus solifugus thrives in glacial ice

Question 22

Class: Clitellata

Sub-class: Hirudinoidea

Answer 22

1. Around 500 species in three orders
2. Body with fixed number of segments
3. Chaetae reduced or absent
4. Cephalic structures much reduced
5. Suckers present on anterior and/or posterior
6. Clitellum
7. Leeches
   Ectoparasitic, predators or scavengers