Rev 10/02/2008
In a classical morphology-based classification system of the Nematoda there are five sub-classes and nineteen orders; those that contain plant-feeding genera are marked with an asterisk (*).
Key to the Orders of Nematoda
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Classification Based on Classical Morphology |
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Classification Based on SSU rDNA |
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| Morphological Basis | SSU rDNA Basis | The classification of organisms above the genus and species levels is not governed by the International Rules of Zoological Nomenclature. In essence, higher classification schemes represent expert opinion based on available evidence. Several classification systems have been proposed for nematodes. New opinions on the relationships among taxa are emerging from molecular data. At the present time, we will use for Nemaplex a widely accepted scheme based on nematode morphological and anatomical characters. |
| Classes | Classes | |
| Sub-classes | Sub-classes | |
| Orders | Orders | |
| Comparison | ||
Key to the Orders of Nematoda |
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Other classification categories:
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Name endings of different levels of taxonomic organization:
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The Phylum Nematoda consists of two classes:
Class Secernentea
1. pore-like or slit-like amphid apertures - labial.
2. deirids present in some near nerve ring.
3. phasmids present, generally posterior.
4. excretory system tubular.
5. cuticle 2 to 4 layers, striated; lateral field present.
6. esophagus varies but has 3 esophageal glands.
7. male generally with 1 testis.
8. caudal alae common.
9. sensory papillae cephalic only, although may be caudal papillae in males.
10. almost exclusively terrestrial, rarely freshwater or marine.
Class Adenophorea
1. amphids post-labial, variable shape, pore-like to elaborate.
2. deirids not seen.
3. phasmids generally absent.
4. hypodermal glands present (excretory?)
5. simple non-tubular excretory system when present.
6. male generally has 2 testes.
7. caudal alae rare.
8. sensory papillae in cephalic region and along body.
9. marine, freshwater, terrestrial.
Maggenti, A.R. 1981. General Nematology. Springer Verlag, New York.
De Ley, P. and Blaxter. M. 2002. Systematic position and phylogeny. In: D. L. Lee (ed) The Biology of Nematodes.
De Ley, P. and Blaxter. M. 2004. A new system
for Nematoda: combining morphological characters with molecular trees, and
translating …
clades into ranks and taxa Nematology Monographs and Perspectives, 2004:
633-653.
De Ley, P., Decraemer, W. & Eyualem-Abebe.
(2006). Introduction, summary of present knowledge and research addressing the
ecology and taxonomy of freshwater nematodes. Pp 3-30 in Eyualem-Abebe, Andrássy,
I. & Traunspurger, W. (Eds). Freshwater
Nematodes, Ecology and Taxonomy.
CABI Publishing,
Wallingford, UK.
Key to the Orders of Nematoda
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