Phylum Nematoda

							                                      Rev 10/99
   Class Chromadorea

                          1. pore-like or slit-like amphid apertures, always labial.
                          2. deirids present in some near nerve ring.    
                          3. phasmids present, generally posterior.
                          4. no hypodermal glands, but hypodermal cells are multinucleate.
                          5. excretory system tubular.
                          6. no caudal glands.
                          7. male generally with a single testis.
                          8. caudal alae common.
                          9. male with paired preanal supplement glands in two sublateral rows.
                         10. sensory papillae cephalic only, although may be caudal papillae in males.                        
                         11. esophagus varies but has 3 esophageal glands.    
                         12. almost exclusively terrestrial, rarely freshwater or marine.

   Class Chromadorea
  (3 sub-classes)

    Sub-class: Rhabditia - no stomal armature.
                           three-part esophagus has corpus, isthmus and
                           metacorpus.  Tri-lobed chamber in terminal  metacorpus.
        Orders:   1. Rhabditida - microbivores in soil; vertebrate and invertebrate parasites.
                                  males with delicate rays in caudal alae.
                                  Rhabditis, Caenorhabditis, Cephalobus,
                                  Steinernema, Heterorhabditis, Acrobeles.
                      2. Strongylida - adults are vertebrate parasites; juveniles 
                                   feed on bacteria or are parasites of annelids/molluscs.
                                   males with prominent rays in lobed caudal alae.
                                   Ancylostoma (hookworm), Enterobius (pin worm)

    Sub-class: Spiruria - wine-bottle esophagus, no valves, all animal 
                          parasites.
        Orders:   1. Spirurida - parasites of terrestrial and aquatic 
                                 vertebrates, include Filarioidea - filarial 
                                 worms. Stoma has a hook. Large nematodes.
                                 Wuchereria bancrofti  (elephantiasis),
                                 Onchocerca volvulus (river blindness), 
                                 Dirofilaria immitis (dog heartworm).
                  2. Ascaridida   - intestinal parasites of vertebrates.
                                  mainly minor parasites of birds and fish and 
                                  <2cm long, except in Ascaris.
                                  Ascaris, Toxocara canis (dog ascarid), Anisakis.
                  3. Camallanida - parasites of terrestrial and aquatic 
                                   vertebrates, with copepods as obligatory secondary host.
                                   Dracunculus medinensis (Guinea worm).
                  4. Drilonematida - parasites of annelids and molluscs.

    Sub-class: Diplogastria - movable stomal armature almost exclusively in 
                               this sub-class in Chromadorea
;                  
                               3-part esophagus with muscular, usually valved, 
                               metacorpus and glandular postcorpus; 
                               microbivores, insect parasites, plant parasites.
        Orders:   1. Diplogastrida - movable teeth in stoma, predators, 
                               omnivores, bacterial and fungal feeders, insect associates.
                               very muscular metacorpus and structured, glandular postcorpus.
                               Odontopharynx.
                  2. Tylenchida - all have movable hollow stylet.             
                                -Aphelenchina -early plant parasites?  Hosts
                                    are Gymnosperms, ferns, ornamentals/nursery, fungi, insects.
                                    males with 6 rays in caudal alae and "rose-thorn" -shaped spicules.
                                - Tylenchina - Parasites of Angiosperms,        
                                    (monocotyledons and dicotyledons), fungi. 
                                    male with at most 1 ray in caudal alae, blade-shaped spicule.
                                - Sphaerulariina - Parasites of insects, and Hexatylina - are other sub-orders.

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