Exam 5 Material (Nemertea/Ribbon Worms: Type of Lophotrochozoa)

Question 1

Is the nemertea a small group?

Answer 1

Yes (only about 100 species)

Question 2

Are almost all of them marine?

Answer 2

Yes

Question 3

How do they get their name?

Answer 3

From their proboscis (a structure that, when turned inside out, extends out from their body—is a synapomorphy for this group)

Question 4

What can be used for entangling their prey, poisoning their prey, or stabbing their prey?

Answer 4

Proboscis (is stored in the rhynchocoel)

Question 5

What is being described (a space inside nemertea’s body where the nose is—they do not have a coelom, but it is believed that this has the remnants of a coelom)?

Answer 5

Rhynchocoel

Question 6

What makes Nemertea special?

Answer 6

First group where we see a circulatory system (they have muscular vessels, but not a heart—can squeeze a blood-like substance throughout their body—probably evolved from a coelomic ancestor/do not have coelom but a COMPLETE digestive tract)