Paraxonchium magnidens
Thorne, 1974
1.5 mm; a = 26; b = 3.6; c = 30-37; V = 60
Body tapering rapidly until lip region is only 1/5 of neck base.
Lateral fields about 1/6 body width with obscure cells from which series
of obscure pores arise, while ventrally another more prominent series come
from gland-like bodies, about 40 anterior to vulva and 25 posterior.
Lip region set off by deep constriction with angular unsymmetrical lips
which are best observed from a face view. Amphids shallow, cup-like,
about half as wide as lip region. Spear 15u long with aperture
occupying 1/3 to 2/5 its length. Spear often somewhat bent, asymmetrical.
Hemizonid conspicuous, opposite nerve ring. Esophagus enlarged near
middle with gland nuclei usually visible. Three nygolaimoid glands
at base of eophagus. Cardia an elongate disc, then conoid.
Intestine usually gorged with detritus whichi appears to have been deribed
from decaying organic material. Ovaries symmetrical, reflexed about
half their length. Eggs 46x90u. Vulva transverse with
sclerotized labia. Prerectum length 2-3 times body width. Rectum
and tail as illustrated. Males not collected and gravid females
contained no sperms. Paraxonchium magnidens is distinctive
because of its size, monosexuality, dorylaimoid spear and asymmetrical
lips.
Habitat: Small numbers from virgin and cultivated soil
in numerous localities of South Dakota, State line between North Dakota
and Montana on Highway 94, Fonda and Minot, North Dakota and Elizabeth,
Minnesota. Specimens from Minot, North Dakota and Hammer, South Dakota
had slightly shorter necks: b = 4.0: 4.3/
The taxonomic postion of Paraxonchium
is questionable. Jairajpuri (1966) assigned it to Dorylaiminae but
it may represent an entirely new group.
(Description- Thorne, 1974)
DNA Sequences Obtained
