The Aquatic Mandibulates




BIO190: The Class: Aquatic Mandibulates: Lesson 20

The Aquatic Mandibulates

The aquatic mandibulates are a part of the phylum arthropoda. Arthropods that possess mandibles (jawlike appendages) are united in the subphylum crustacea.

Mandibles = jawlike appendages

Phylum Arthropoda

Subphylum Crustacea: 5 classes
Explore these web sites for more information:
About Lobsters
Braer Oil Spill and Lobsters
1. characteristics
  1. cephalothorax, abdomen
  2. mostly marine
  3. 2 pair antennae
  4. 1 pair mandibles
  5. 2 pair maxillae
  6. appendages biramous (fig. 20-3)
    (exception - first antennae)
  7. respiratory system
    1. thin areas of cuticle or
    2. gills
  8. circulatory system-Open(figs. 20-5 & 20-6)
    1. dorsal heart
      (single chamber)
    2. arteries
    3. sinuses
    4. no viens
    5. no separation of hemolymph from interstital fluids
  9. rostrum
  10. telson
  11. carapace
    1. covers cephalothorax
    2. calcium salts
  12. appendages (figs. 20-2 --> 20- 4)
  13. hemocoel
  14. muscular system
    1. flexors
    2. extensors
  15. excretory system (fig. 20-7)
  16. nervous system (fig. 20-5)
    (common with annelids)
  17. sensory
    1. eyes (fig. 20-8)
      (ommatidia)
    2. statocysts
      (statoliths)
    3. reproduction
      1. mostly dioecious
      2. brood eggs
    4. development
      1. some direct
      2. some with metamorphosis (fig. 20-9)
        (nauplius larva)
    5. ecdysis (fig. 20-10 --> 20-12)
    6. hormones (pp. 391-392)
    7. nutrition and feeding habits
      1. wide variation in foods
        
        availability
        environmental
      2. filter feeders
      3. predators
      4. scavengers
Class Remipedia (fig. 20-14)
Remipedia is a very small, recently described class of Crustacea. The 10 species described so far have come from caves with connections to the sea. Remipedes have very primitive features.
Class Cephalocardia (fig. 20-15)
Cephalocardia is also a small group, with only nine species known. Cephalocards occur along both coasts of the United States, in the West Indies, and in Japan.
Class Branchiopoda (fig. 20-16)
Branchiopoda also represents a crustacean type with some primitive characteristics.
Class Maxillopoda (6 subclasses)
The class Maxillopoda includes a number of crustacean groups traditionally considered classes themselves.
Subclass Cirripedia
The Cirripedia includes the barnacles, which are usually enclosed in a shell of calcareous plates, as well as three smaller orders of burrowing or parasitic forms.

Class Malocostraca (4 orders)
The Malacostraca is the largest class of Crustacea and shows great diversity. This class is also economically important.
- largest class
- economically important
Once you have completed the lesson, you should go to Assignment 20-1.

E-mail Sylvester Allred at Syl.Allred@nau.edu

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