Phylum Arthropoda:

Subphylum Mandibulata:

Class Crustacea

Class Crustacea

"Crusted Forms" - hard flexible crust

Over 38,000 species

Nearly all are aquatic - "Insects of the Sea"

Microscopic to Largest Living Arthropods

Characteristics of Crustacea

1. External

a. Appendages

b. Tagmata

c. Exoskeleton

2. Feeding and Digestion

a. Nearly all are suspension filter-feeders

b. Larger species predator/scavengers

c. Appendages specialized for cutting, tearing, collecting

d. Foregut enlarged into cardiac and pyloric stomach

e. Midgut bears two digestive glands (hepatopancreas)

3. Gas Exchange, Circulation, and Excretion

a. Respiration

b. Circulatory System

c. Excretion

4. Nervous and Sensory Structures

a. CNS is typical for arthropods:

b. Eyes of two types

c. Prioprioceptors and statocysts

d. Sensory hairs for mechano- and chemoreception

Class Crustacea

Subclass Malacostraca

Subclass Malacostraca: Order Decapoda ("Ten Legs")

Subclass Malacostraca: Order Amphipoda ("Double Legs")

Subclass Malacostraca: Order Isopoda ("Same Legs")

Subclass Branchiopoda

Subclass Ostracoda

Subclass Copepoda

Subclass Cirripedia