Aphelenchoides pusillus
Filipjev, 1934
Syn. Aphelenchus pusillus Thorne, 1929
Photo Gallery- Long's Peak, Colorado

Description (from Thorne, 1929)
    Characters somewhat similar to Aphelenchus parietinus Bastian but with these differences: Body only .31 mm in length.  Spear much larger with distinct trilobed base.  Tail ending in a mucro formed by a sudden contraction of the terminus.
    The transverse striae are exceedingly fine, being scarcely visible.  There are two very indistinct wings.  The lip region is set off and has a cutinous framework about the entrance to the pharynx.  A narrow vestibule reaches half the spear length, at its base forming an indistinct guiding ring for the spear.  The median bulb is as long as the neck width and almost as wide as the body cavity with a conspicuous valvular apparatus near its center.  The nerve ring encircles the narrow tube leading from the bulb to the intestine one body width below the bulb.  The renette pore is opposite the nerve ring.  The anus is distinct and from it the slender rectum extends forward two anal body-widths.  A prominent feature is a ventral narrowing of the body just posterior to the elevated vulva.  The anterior ovary is out-stretched the posterior rudimentary and only three body-widths long.  Eggs are three times as long as the vulva body-width and fill the body cavity.
    Five specimens, all of which are adult females.