Lophophorates: Bryozoans and Brachiopods


What are Lophophorates?


Lophophorate Evolution


Phylum Bryozoa


Characteristics of Bryozoa

1. Zooids are small (<1 mm), attached to a branched trunk

2. Body covered with a chitinous cuticle (may be calcified)

3. Zooids are tricoelomate, tentacles are folds of mesoderm

4. Lophophore is slowly protruded by coelomic fluid and rapidly withdrawn by retractor muscles

5. Feeding tentacles bear cilia that move food particles

6. U-shaped digestive tract, anus exits below lophophore

7. Lack an excretory system (sequester N wastes); rudimentary circulatory system

8. As a colony grows and divides, old zooids degenerate or become defensive avicularia with movable jaws


Phylum Brachiopoda


Characteristics of Brachiopoda

1. Two Basic Types

2. Characteristics of Bivalve Shell

3. Pedicle or stalk exits by through a hole in ventral plate

4. Internal Structures