Chromadorea

Chromadorea
Scientific classification
Kingdom:	Animalia
Phylum:	Nematoda
Class:	Chromadorea
Subclass:	Chromadoria

The Chromadorea are a class of the roundworm phylum, Nematoda. They contain a single subclass (Chromadoria) and several orders. With such a redundant arrangement, the Chromadoria are liable to be split up if the orders are found to form several clades, or abandoned if they are found to constitute a single radiation.

Formerly, they were treated as a subclass in the paraphyletic "Adenophorea" assemblage, which has been by and large abandoned by modern authors. It is also suspected that the Chromadorea may not be monophyletic as delimited here; at least the Monhysterida seem to be a distinct and far more ancient lineage than the rest.

Members of this class' bodies usually have annules, their amphids elaborate and spiral, and they all have three esophageal glands. They usually live in marine sediments, although they can live elsewhere. They have more sophisticated pharynxs than most roundworms.

Provisionally, the following orders are placed here:

The Benthimermithida are also occasionally placed here.

The Ascaridida appear to be nested within Rhabditida.

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Wikipedia