Nematomorpha

Horsehair worm Gordius aquaticus emerging from cricket Anonconotus alpinus, copyright Roger de La Grandière.

Belongs within: Ecdysozoa.
Contains: Gordionus.

The Nematomorpha, Gordian or horsehair worms, are a group of elongate worms that are parasitic as larvae on insects or crustaceans, emerging into water upon maturity. A single genus Nectonema is marine and bears dorsal and ventral rows of cuticular natatory bristles as an adult; the remaining genera (forming the taxon Gordiida) are found in freshwater as adults and lack bristles (Schmidt-Rhaesa 2002).

See also: Gordians.

Characters (from Miller & Harley 1996): Body extremely long and threadlike, without distinct head. Body wall with thick cuticle, cellular epidermis, longitudinal cords, and muscle layer of longitudinal fibres. Nervous system with anterior nerve ring and ventral cord. Larva endoparasitic, bearing protrusible proboscis armed with spines and terminal stylets.

<==Nematomorpha
    |--Nectonema Verrill 1879 S-R02
    |    |--N. agile Verrill 1879 S-R02
    |    |--N. melanocephalum Nierstrasz 1907 S-R02
    |    |--N. munidae Brinkmann 1930 S-R02
    |    `--N. svensksundi Bock 1913 S-R02
    `--Gordiida [Gordioida] S-R02
         |--Gordionus S-R02
         |--Noteochordodes Miralles & Villalobos 2000 S-R02
         |    `--N. dugesi (Camerano 1898) S-R02
         |--Pseudogordius Yeh & Jordan 1957 S-R02
         |    `--P. tanganyikae Yeh & Jordan 1957 S-R02
         |--Semigordionus Heinze 1952 S-R02
         |    `--S. circumannulatus Heinze 1952 S-R02
         |--Beatogordius Heinze 1934 [incl. Chordodiolus Heinze 1935] S-R02
         |    |--B. echinatus (Linstow 1901) [=Chordodiolus echinatus] S-R02
         |    |--B. raphaelis S-R02
         |    `--B. ugandensis S-R02
         |--Parachordodes Camerano 1897 S-R02
         |    |--P. maculatus S-R02
         |    |--P. pustulosus (Baird 1853) S-R02
         |    `--P. tolosanus (Dujardin 1842) S-R02
         |--Euchordodes Heinze 1937 S-R02
         |    |--E. libellulovivens Heinze 1937 S-R02
         |    |--E. malaysiensis Inoue 1966 S-R02
         |    `--E. nigromaculatus Poinar 1991 S-R02
         |--Pseudochordodes Carvalho 1942 S-R02
         |    |--P. bedrigae (Camerano 1896) S-R02
         |    |--P. gordioides (Montgomery 1898) S-R02
         |    `--P. pardalis (Camerano 1893) S-R02
         |--Paragordionus Heinze 1835 S-R02
         |    |--P. bohemicus Havlik 1947 S-R02
         |    |--P. dispar (Müller 1927) S-R02
         |    |--P. rautheri Heinze 1937 [=Gordionus rautheri] S-R02
         |    `--P. vejdovskyi (Janda 1895) S-R02
         |--Neochordodes Carvalho 1942 S-R02
         |    |--N. meridionalis (Carvalho & Feio 1950) [=Pseudochordodes meridionalis] S-R02
         |    |--N. occidentalis (Montgomery 1898) [=Pseudochordodes occidentalis] S-R02
         |    |--N. punctatus Miralles & Villalobos 1996 S-R02
         |    |--N. talensis (Camerano 1897) S-R02
         |    `--N. uniareolatus Carvalho 1946 S-R02
         |--Chordodes Creplin 1847 S-R02
         |    |--C. annulatus (Linstow 1906) S-R02
         |    |--C. caledoniensis S-R02
         |    |--C. delmaede Villalobos 1995 S-R02
         |    |--C. ferganensis Kirjanova & Spiridonov 1989 S-R02
         |    |--C. morgani Montgomery 1898 S-R02
         |    |--C. queenslandi S-R02
         |    `--C. sajanensis Spiridonov 2000 S-R02
         |--+--Dacochordodes Capuse 1965 S-R02
         |  |    `--D. bacescui Capuse 1965 [incl. Euchordodes parvulus Canadjija 1956] S-R02
         |  |--Lanochordodes Kirjanova 1950 S-R02
         |  |    `--L. zeravshanicus Kirjanova 1950 S-R02
         |  |--Pantachordodes Heinze 1954 [=Neochordodes Heinze 1952 non Carvalho 1942] S-R02
         |  |    `--P. europaeus (Heinze 1952) [=Neochordodes europaeus] S-R02
         |  `--Spinochordodes Kirjanova 1950 S-R02
         |       |--*S. tellinii (Camerano 1888) [=Pantachordodes tellinii] S-R02
         |       `--S. baeri (Camerano 1896) [=Pantachordodes baeri] S-R02
         |--+--Progordius Kirjanova 1950 S-R02
         |  |    `--P. maculatus Kirjanova 1950 S-R02
         |  |--Digordius Kirjanova 1950 S-R02
         |  |    |--D. excavatus Kirjanova 1950 S-R02
         |  |    `--D. trinacris Kirjanova 1954 S-R02
         |  `--Paragordius Camerano 1897 S-R02
         |       |--P. flavescens Linstow 1906 S-R02
         |       |--P. stylosus (Linstow 1883) S-R02
         |       |--P. tricuspidatus (Dufour 1828) S-R02
         |       `--P. varius (Leidy 1851) S-R02
         `--+--Acutogordius Heinze 1952 S-R02
            |    |--A. australiensis Spiridonov 1984 S-R02
            |    `--A. incertus (Villot 1874) S-R02
            `--Gordius Linnaeus 1758 [Gordiidae] S-R02
                 |--*G. aquaticus Linnaeus 1758 H62
                 |--G. argillaceus Linnaeus 1758 L58
                 |--G. borisphaenicus Spiridonov 1984 S-R02
                 |--G. difficilis (Montgomery 1898) S-R02
                 |--G. dimorphus WPT01
                 |--G. elongiporus Schmidt-Rhaesa 2000 S-R02
                 |--G. impressus Schneider 1866 S-R02
                 |--G. medinensis Linnaeus 1758 L58
                 |--G. paranensis Camerano 1892 S-R02
                 |--G. robustus Leidy 1851 [=G. aquaticus robustus, G. villoti robustus] S-R02
                 |--G. tenuifibrosus M79
                 `--G. villoti Rosa 1882 S-R02

*Type species of generic name indicated

REFERENCES

[H62] Howell, B. F. 1962. Worms. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt W. Miscellanea: Conodonts, Conoidal Shells of Uncertain Affinities, Worms, Trace Fossils and Problematica pp. W144–W177. Geological Society of America, and University of Kansas Press.

[L58] Linnaeus, C. 1758. Systema Naturae per Regna Tria Naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Laurentii Salvii: Holmiae.

Miller, S. A., & J. P. Harley. 1996. Zoology 3^rd ed. Wm. C. Brown Publishers: Dubuque (Iowa).

[M79] Müller, A. H. 1979. Fossilization (taphonomy). In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A2–A78. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[S-R02] Schmidt-Rhaesa, A. 2002. Are the genera of Nematomorpha monophyletic taxa? Zoologica Scripta 31 (2): 185–200.

[WPT01] Wharton, D. A., R. Poulin & C. L. Tyrell. 2001. Parasites of anostostomatid insects. In: Field, L. H. (ed.) The Biology of Wetas, King Crickets and Their Allies pp. 259–267. CABI Publishing: Wallingford (UK).