Tylenchida

Tom Powers *

     ====== Tylenchina 
     |
     |===== Aphelenchina 
<<===|
     |===== Sphaerulariina 
     |
     ====== Hexatylina 

Maggenti, 1991

Containing clade(s): Diplogasteria

Table of Contents

Introduction

References

Introduction

The labial region in Tylenchida is variable; it may be distinctly set off or smoothly rounded and well developed. The hexaradiate symmetry is most often retained or discernible. The amphids are porelike, oval, slitlike, or clefts located on the lips. The internal circlet of six sensilla may be lacking. The external circle of 10 sensilla is often evident, however, these may be reduced to a visible four or some may be doubled. The hollow stylet is the product of the cheilostome (conus, "guiding apparatus," and framework) and the esophastome (shaft and knobs). Throughout the order and its suborders the stylet may be present or absent and may or may not be adomed with knobs. The variable esophagus is most often divisible into the corpus, isthmus, and glandular posterior bulb. The corpus is further divisible into the procorpus and metacorpus. The metacorpus is generally valved but may not be in some females and males, and the absence is characteristic of some taxa. The orifice of the dorsal esophageal gland opens either into the anterior procorpus or just anterior to the metacorporal valve. The excretory system is asymmetrical and there is but one longitudinal collecting tubule. Females have one or two genital branches; when only one branch is present it is anteriorly directed. Except for sex-reversed males there is only one genital branch. Males may have one (= phasmid) or more caudal papillae. The spicules are always paired and variable in shape; they may or may not be accompanied by a gubenaculum.

References

Maggenti, A.R. 1991. Nemata: higher classification. In:  Manual 
          of Agricultural Nematolgoy, W.R. Nickle [ed.] Marcel 
          Dekker, Inc., New York.

About this page

Page constructed by Marcella Shaver-Adams, madams@unlgrad1.unl.edu.

Tom Powers
E-mail: tpowers@unlinfo2.unl.edu.
University of Nebraska-Lincoln, Department of Plant Pathology, 406 Plant Sciences Hall, P.O. Box 830722, Lincoln, NE 68583-0722

Page copyright © 1997 Tom Powers and the Society of Nematology Systematics Resources Committee

Last saved 16 July 1997

Title Illustration

Merlinius sp.