Week Four: Phylum Acanthocephala (Chapter 9)

Question 1

What are acanthocephalans?

Answer 1

Thorny-headed worms

Question 2

Who do acanthocephalans mostly parasitize?

Answer 2

Marine and freshwater fish

Aquatic birds

Question 3

What is the thorny headed worm of swine?

Answer 3

Macracanthorhynchus hirundinaceus

Question 4

What is the thorny headed worm of dogs?

Answer 4

Oncicola canis

Question 5

What are some morphologic features of acanthocephalans?

Answer 5

Elongate, cylindric, tapering at both ends, dioecious (females are larger than males)

Question 6

What are the hook things on an acanthocephalans head called?

Answer 6

Proboscis (retractable proboscis)

Question 7

What are acanthocephalans organ of attachment?

Answer 7

Retractable proboscis

Question 8

How do acanthocephalans absorb nutrients?

Answer 8

Through tegument

Question 9

Explain the life cycle of acanthocephalans

Answer 9

• Eggs voided in feces of definitive host
• Intermediate host ingests the egg
• Larva hatches in intermediate host
• Larva develops into acathella, then cystacanth
• Definitive host ingests arthropod intermediate host
• Attaches to wall of small intestine

Question 10

Macracanthorhynchus hirudinaceus:

Host, location of adult, intermediate host, transmission route, common name

Answer 10

Host: Pigs
Location: small intestinal mucosa
I. Host: Dung beetle
TR: Ingestion of infective dung beetle
CN: Thorny headed worm

Question 11

Oncicola canis:

Host, location of adult, intermediate host, transmission route, common name

Answer 11

Host: Dogs
Location of host: Small intestinal mucosa
I. Host: Dung beetle
TR: Ingestion of infected dung beetle
CN: Thorny-headed worm of dogs