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Axonchium micans
 
Axonchium micans Thorne, 1939
This week's Nematode of the Week is a not-uncommon inhabitant of tallgrass prairie soils. We find it in moderate numbers (1 to 8 per 100 cc soil) at both Nine Mile Prairie (near Lincoln, Nebraska) and at the Konza Prairie LTER in Manhattan, Kansas. Presumably herbivorous (or perhaps omnivorous), A. micans is one of the larger nematodes recovered from soil samples. Description (from Thorne,
G. 1939. A monograph of the nematodes of the superfamily Dorylaimoidea.
Capita
Female: 2.7 mm; a = 40; b = 3.6; c = 80; V = 7 5213 Cuticle
with conspicuous radial striae. Amphids encompassing the head, forming
a deep pocket about the lips. Lips somewhat hemispherical, conspicuous.
Spear slightly longer than width of lip region, spindle shaped, the aperture
occupying about one-fourth of its length. About two-thirds of esophagus
enlarged. Cardia cylindrical or slightly clavate, its length equal
to about one-half the body width. Intestinal cells filled with very
fine, brown granules. Vagina extending almost two-thirds across body.
Anterior female sexual branch a rudimentary tube two or three times as
long as the body width; posterior branch normal. Prerectum length
about four times body width.
Notes:
Determined by Peter Mullin. We have also recovered A. gigas
from our Konza samples; adults of the two species may be readily differentiated
based on body size (A. micans is usually less than 3 mm in length,
while A. gigas almost always exceeds 4 mm in length), although they
are in all other respects very similar. It is often difficult to
place juveniles in either species based on morphology, but the two species
appear to be distinct based on sequence of the 18s rDNA.
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