Annelida Flashcards
What are the four subclasses of annelida presented in class?
- polychaeta
- Clitellata
- Sipuncula
- Echiura
Define Tagmatization?
differentiated groups of segments specialized to perform specific functions for the whole organism (head, thorax, abdomen)
POLYCHAETA: apomorphies?
- Parapodia ????
- Nuchal organs - sensory organs by the neck
- pedal ganglia
- pair of pygidial cirri
FUN FACT: GIANT AXONS, ANTERIOR DORSAL BRAIN
CLITELLATA: apomorphies?
- lack parapodia
2. clitellum: the thick band around earthworms - girdle - used as a reproductive structure.
What is the purpose of Chaetae and what is it made of?
- Made of Beta Chitin
- used mainly for traction
Difference between sedentaria - oligochaeta vs polychaetae brain?
polychaeates have anterior dorsal brains whereas sendentaria - oligchaetae have posterior, dorsal brian.
Clitellata > Oligochaetae > HIRUDINOMORPHS
What are they and their apomorphies?
Hirudinomorphs are leeches!
They have:
1. posterior sucker/ anterior suckers (remember they can walk?)
2. unsegmented body but with superficial marks
3. No chaetae
4. unpaired mid-ventral gonopore
5. lives as a parasite
6. have sensory papillae - like those tiny rings on their skin
ECHIURA: aka the spoonworms! What are their apomorphies?
- pair of anterior ventral chaetae
- deposite feeders
- 2 posterior rings of chaetae (beta chitin)
- prostromium (upper half of the spoon)
- prostomial and trunk coelom
- intestinal siphon - to bypass H2O
SIPUNCULA (peanut worms!)
What are their apomorphies?
- Introverts (but they can evert too!)
- Tentacles & tentacular coelom
- J-Shaped intestinal tract
- Intestinal ciliary grooves! (water shunt?)
- Cuticle with scattered hooks
Hemerythrin in cells
What are the two major clades in Annelida?
Errantia - polychaetae
Sedentaria - pogonophorons, hirudinidae, chiura, clitellata,
