What is Nematomorpha?
{{Taxobox | name = Nematomorpha | image = Paragordius tricuspidatus.jpeg | image_caption = ''Paragordius tricuspidatus'' | image_width = 250px | domain = [[Eukaryota]] | regnum = [[Animal]]ia | unranked subregnum = [[Cycloneuralia]] | unranked superphylum = [[Nematoida]] | phylum = '''Nematomorpha''' | phylum_authority = Vejdovsky, 1886 | subdivision_ranks = [[Class (biology)|Classes]] | subdivision = Nectonematoida<br/>Gordioidea }} The '''Nematomorpha''' ('''horsehair worms''') are a [[phylum]] of [[Parasitism|parasitic]] [[cycloneuralia]]n [[animal]]s. They look similar to [[nematode]] worms and live in similar [[environment]]s, which is why their names are similar. They are sometimes called '''Gordiacea'''.<ref>The name stems from the legendary [[Gordian knot]], because nematomorphs often tie themselves in knots. Piper, Ross 2007. ''Extraordinary animals: an encyclopedia of curious and unusual animals'', Greenwood Press.</ref> They range in size from {{convert|50|to|100|cm|in}} long and in extreme cases may be up to 2 meters long. They are {{convert|1|to|3|mm}} in [[diameter]]. Horsehair worms can be discovered in damp areas such as watering troughs, streams, puddles, and [[cistern]]s. About 326 species are known and an estimate suggests that there may be about 2000 species worldwide.<ref>{{cite journal|title=Global diversity of hairworms (Nematomorpha: Gordiaceae) in freshwater|author=Poinar Jr., G|journal=Hydrobiologia|volume=595|issue=1|year=2008|pages=79–83|doi=10.1007/s10750-007-9112-3|s2cid=37985613}}</ref> Fossilized worms have been reported from [[Lower Cretaceous]] Burmese [[amber]] 100–110 million years ago.<ref>Poinar, George; Buckley Ron 2006. Nematode (Nematoda: Mermithidae) and hairworm (Nematomorpha: Chordodidae) parasites in early Cretaceous amber. ''Journal of Invertebrate Pathology'' '''93'''(1):36–41</ref> ==Life cycle== The adult worms are free living and, in North America, are usually found only in the summer months in or near shallow water.<ref>{{cite journal|title=Seasonal occurr