Nygolaimus paratenuis
Thorne, 1974

Description (from Thorne, 1974)
    Body twisted until sometimes it forms a half spiral with amphids seen from a dorsal view.  Lateral fields 1/3 body width.  Lip region rounded with distinct papillae.  Tooth about 11 um long, slender, deltoid, almost as long as width of lip region. Esophagus a slender tube in anterior third, then gradually expanding until it fills body cavity. Cardia cylindroid, 1/5 body width, usually obscured by cardiac glands.  Vulva transverse, vagina typical.  Ovaries reflexed about 2/3 distance back to vulva.  Rectum and prerectum each about length of anal body diameter.  Tail dorsally arcuate to bluntly rounded terminus.
    The single male collected possessed normal testes but associated females were not spermatized.  Tail similar to that of Nygolaimus parvus.
    Nygolaimus paratenuis somewhat resembles N. tenuis but the pharynx is shorter, the spear longer and body width greater.
    Habitat: A very common species throughout the Northern Great Plains from both cultivated and virgin soils.