Genus Geocenamus
Thorne, 1968
Photo Gallery- Haughton Crater

Body medium sized. Labial region bulbous. SEM face view well marked, round labial disc. First lip annulus divided into six sectors, lateral sectors smaller. Labial framework weakly developed. Lateral field with six lines. Deirids absent (but said to be inconspicuous by Siddiqi, 1986). Stylet slender, 25-130 um long, cone longer than shaft. Tail conoid to almost cylindroid. Spicules without velum, blunt ended. Gubernaculum not protruding from cloaca.
(Description-    )

Diagnosis:  Tylenchorhynchinae.  Bodies cylindroid, tapering near extremities.  Lip region with 5 annules, set off by deep constriction.  Cephalic framework weakly developed.  A refractive, perioral disc present.  From this disc a slender, tubular spear guide extends back about 8u.  Spear exceedingly slender, 27u long with strong sloping knobs, its muscles attached to cephalic framework.  Ovaries outstretched.  Spermatheca spheroid, about 1/2 body width.  Post rectal blind sac extending 2/3 distance into tail.  Female terminus rounded, male tail slightly arcuate, enveloped by broad bursa.

Geocenamus is distinctive because of the perioral disc from which the slender spear guide extends back almost 1/3 length of the exceedingly slender spear.  The head and spear are reminiscent of those of Dolichodorus rather than Tylenchorhynchus.
(Description- Thorne, 1968)

Type species: Geocenamus tenuidens Thorne, 1968

     Geocenamus arealoferus
     Geocenamus arcticus
     Geocenamus deserticola
     Geocenamus kirjanovae
     Geocenamus longus
    Geocenamus superbus
     Geocenamus tenuidens
     Geocenamus tokobaevi
     Geocenamus uralensis

Species found:        at:
G. tenuidens Konza Prairie