Thorne & Malek, 1968
L = 1.0 mm; V = 52
Body arcuate when relaxed, tapering anteriorly to a bluntly conoid
without visible annules. Lateral fields marked by 4 incisures,
the outer ones crenate. Spear
long with moderately large, slightly cupped knobs, their muscles attached
to sclerotized band about base of head. Dorsal esophageal gland outlet
about 2u behind spear knobs. Esophagus tapering to a narrow tube
where it joins the median bulb. Basal bulb about as long as neck
width with excretory pore opposite anterior end. Hemizonid 1 annule
anterior to pore. Deirids not seen. Ovaries outstretched, oocytes
in single file. Spematheca about half as long as body width, packed
with sperms. Eggs almost 3 times as long as body width. Intestine
extending entire length of tail cavity, the rectum attached to ventral
side. Tail with
40-45 annules and massive thick cuticle around hemispheroid terminus. Male
with lateral field, bursa, spicula, gubernaculum and phasmid as illustrated.
Tylenchorhynchus robustus is immediately recognized by the long
cylindroid female tail with smooth rounded terminus, and bluntly rounded
lip region without visible annules.
Habitat: Four females and 6 males from soil about roots
of native pasture grasses, Range Field Station, Cottonwood, South Dakota.
(Description- Thorne & Malek, 1968)
DNA Sequences Obtained