Aphelenchoides dactylocerus
Hooper, 1958
Measurements (from Hooper, 1958)
L = 445 u; a = 26.1; b = 8.1; c = 10.5; V = 67
Measurements (from Hooper, 1958)
Body cylindrical, tapering at both ends. Cuticle
finely annulated, the annules 0.8-1.0 u wide in mid body region.
Lateral fields prominent, marked by three incisures, occupying between
a quarter and a fifth of the total body-width. Lateral fields begin
about half-way between head and oesophageal bulb and end midway between
anus and tail terminus. Head slightly offset, without annulations.
An end-on view shows six lips but no papillae or amphidial openings are
visible. Stylet 10 u long made up of the usual two parts with distinct
basal thickenings. Stylet tip surrounded by guide ring which appears
star-shaped when seen from the front and as two short rods in lateral view.
First region of oesophagus narrow with well marked lumen followed by prominent,
muscular, median bulb in the centre of which is a conspicuous valve with
crescentic thickenings. Elongated oesophageal glands lying dorsally
along intestine and about three body-widths long: dorsal gland duct opening
into lumen of oesophagus just in front of valve. Intestine
begins as tube immediately behind median bulb, widens gradually and runs
straight to narrow rectum which is twice as long as the anal body-width.
Anus distinct; behind it the tail narrows suddenly and then gradually tapers
to the tip; tail over four times as long as the anal body-width.
Tail terminus convex-conoid with sharply pointed, ventrally placed, mucro.
Tail curves ventrally when relaxed by gentle heat and has a finger like
appearance; hence the specific epithet of dactylocercus. Nerve
ring situated just behind median oesophageal bulb. Excretory pore
on ventral surface usually just in front of nerve ring but may be as far
forward as centre of median bulb. Ovary outstretched, consisting
of a single row of about twelve oocytes. Oviduct short, only one
egg seen at a time in the uterus. Eggs just over two and a half times
as long as broad. Post vulval sac short, usually less than one body-width
long. Vagina directed obliquely backwards. Vulva transverse
slit about one third of a body-width long.
No males have been found.
Type habitat: Pot of soil growing young Sitka spruce
trees, Picca sitchensis (Borg.) Carr. -- Nematology Department,
Rothamsted.
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