Characteristics Charts of the Orders Dorylaimida and Triplonchida
Morphology and Anatomy:
Nematodes in the family Longidoridae are
identified by the greatly elongated odontostyle
(50-200 Ám long) plus the odontophore which may be plain or heavily flanged.
Loof and Coomans observed that the genera Longidorus and Paralongidorus
on the one hand, and Xiphinema on the other,
exhibit distinct differences with regard to location, shape, and size of the
nucleus of the dorsal esophageal gland. These and other observations
support the subdivision of the Longidoridae into two subfamilies, Longidorinae
- The genera Xiphinema and Longidorus
appear on the basis of morphology to be very closely related. These
two genera are readily distinguished from other genera of the Dorylaimoidea.
- The species of Xiphinema and Longidorus are relatively
is 2 to 8 mm in length.
is 2 to 5 mm in length.
- The species of Xiphinema and Longidorus are also
characterized by the presence of a very long odontostyle. The stylet
and its extension are approximately 150 Ám or more in length.
1. In Xiphinema, the guiding ring is located near the base of the odontostyle,
just before its junction with the stylet extension (odontophore).
A flanged odontophore is characteristic of Xiphinema.
2. In Longidorus, the guiding ring is located 2 lip region
widths from the anterior end; no flanges occur on the posterior end of the
- Both Xiphinema and Longidorus have a 2-part
typical of most Dorylaimida, with a slender anterior part and swollen
glandular and muscular posterior bulb.
- In Xiphinema and Longidorus, the cross-sectional
configuration of the spear is cylindrical and the cross-section of the
odontophore is tri-radiate as in the esophagus. The esophagus has a
- Males of Xiphinema and Longidorus have paired pre-anal
papillae and a ventromedian row of supplements. The number and
arrangement of these papillae are of importance in distinguishing species.
But, males are rare in most species.
Males have paired spicules,
but no gubernaculum;
they have no bursa.
- Females of Xiphinema usually have two, but sometimes one, ovaries. Females of Longidorus
have 2 ovaries. The ovaries, when both occur, are opposed and reflexed.
Robertson and Taylor, Nematode Ultrastructure. The Feeding Apparatus of Longidorus
and Xiphinema, Scottish Horticultural Research Institute (1977), p. 3.
Lamberti, Taylor and Seinhorst, Nematode Vectors of Plant Viruses, New York:
Plenum Press (1974), pp. 40-41.
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