Monhysterida

Belongs within: Cycloneuralia.
Contains: Sphaerolaimoidea.

The Monhysterida are a group of free-living nematodes, often characterised by their outstretched female reproductive system though this has been shown to occur in members of other nematode lineages.

Characters (from Coomans & Eyualem-Abebe 2006): Small to medium-sized, more or less slender nematodes. Body slightly attenuated towards the rounded or truncated anterior body end, more strongly attenuated towards tail end. Cuticle finely striated (often appearing smooth under light microscopy) or clearly annulated. Anterior sensilla 6 + 10 or 6 + 6 + 4; six inner labial sensilla papilli- or setiform; six outer labial sensilla and four cephalic sensilla usually setiform; setae may be jointed. Amphids typically with round fovea (sometimes described as unispiral or pseudospiral). Dorsal or subdorsal ocelli may be present. Female reproductive system outstretched, either with two ovaries or only one (anterior) ovary. Male reproductive system with either two testes or only one (anterior) testis. Pre-anal genital papillae (supplements) rarely present. Caudal glands mostly confined to tail, opening separately or through a common pore.

<==Monhysterida
    |--Linhomoeina [Siphonolaimoidea]LB02
    |    |--LinhomoeidaeLB02
    |    |--FusivermidaeLB02
    |    `--SiphonolaimusL86 [SiphonolaimidaeLB02]
    |         |--S. obscurus Boucher & Helléouet 1977L86
    |         `--S. tubicen Ott 1972L86
    `--Monhysteroidea [Monhysterina]NT02
         |--MonhysteridaeLB02
         |    |--Monhystera Bastian 1865E86
         |    |    |--M. megacephala Joubert & Heyns 1980NT02
         |    |    |--M. paludicola Andrassy 1981NT02
         |    |    `--M. stagnalis Bastian 1865NT02
         |    |--DiplolaimelloidesNT02
         |    |    |--D. meyliL02
         |    |    `--D. pallustris Tsalolikhin 1985NT02
         |    |--DiplolaimellaNT02
         |    |    |--D. dievengatensis Jacobs, van de Velde et al. 1990NT02
         |    |    `--D. schneideri Chitwood & Murphy 1964NT02
         |    |--Geomonhystera disjunctaL02
         |    |--Anguimonhystera Andrassy 1981E86
         |    |    |--A. ampliceps (Goffart 1950) [=Monhystera ampliceps]E86
         |    |    |--A. stadleri (Goffart 1950) [=Monhystera stadleri]E86
         |    |    `--A. tenuissima (Goffart 1950) [=Monhystera tenuissima]E86
         |    |--Eumonhystera borealis Turpeenniemi 1977NT02
         |    `--Monhystrella perelegantula (De Coninck 1943)NT02
         `--SphaerolaimoideaLB02

*Type species of generic name indicated

References

Coomans, A., & Eyualem-Abebe. 2006. Order Monhysterida. In: Eyualem-Abebe, W. Traunspurger & I. Andrássy. Freshwater Nematodes: Ecology and Taxonomy pp. 574–603. CABI Publishing.

[E86] Eder, R. 1986. Nematoda from continental subterranean aquatic habitats. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 125–132. E. J. Brill/Dr W. Backhuys: Leiden.

[L02] Lee, D. L. 2002. Behaviour. In: Lee, D. L. (ed.) The Biology of Nematodes pp. 369–387. Taylor & Francis: Florence (Kentucky).

[LB02] Ley, P. de, & M. Blaxter. 2002. Systematic position and phylogeny. In: Lee, D. L. (ed.) The Biology of Nematodes pp. 1–30. Taylor & Francis: Florence (Kentucky).

[L86] Lorenzen, S. 1986. Nematoda: interstitial nematodes from marine brackish and hypersaline environments. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 133–142. E. J. Brill/Dr W. Backhuys: Leiden.

[NT02] Nicholas, W. L., & J. W. H. Trueman. 2002. The taxonomy of the family Xyalidae Chitwood, 1951 (Monhysterida: Nematoda): a cladistic analysis. Nematology 4 (4): 453–470.