One new and three known species of Paratylenchus ( Nematoda : Tylenchulidae ) from Manipur , India

Three known species of Paratylenchus i.e., P. canchipur, P. lepidus , P. longicaudatus and one new species, Paratylenchus thysanolus, are reported from Manipur, India with descriptions and illustrations.


Remarks
The morphological characters and dimension of the present specimens are in agreement with those original descriptions and dimensions provided by Mohilal & Dhanachand (2004).

Paratylenchus lepidus Raski 1975
Dimensions: Refer Table 1 Description Female: Body arcuate ventrally to an open C after fixation, slightly more curved ventrad posterior to vulva.Body cuticle marked by fine transverse striae, about 1.0µm wide.Head rounded, without distinct annules.Stylet knobs squared-off or slightly posteriorly directed.Dorsal oesophageal gland orifice opens into lumen of oesophagus, about 7±0.8 (6-8) µm behind the basal knobs.Oesophagus composed of distinct amalgamated procorpus and corpus with posteriorly located valve plates, narrow isthmus and rather rounded basal bulb.Cardia small, round.Nerve ring surrounds isthmus.
Ovary mono-prodelphic and outstretched.Spermatheca ovoid, prominent, with small spermatozoa.Vulva flaps distinct, large and rounded.Tail tapers gradually to a finely rounded terminus.Lateral field with four incisures, inner two slightly less distinct than outer two.
Male: Not found.

Habitat and locality:
Soil around the roots of Crotalaria juncea Linn.from Wakha, Imphal East district, Manipur.

Remarks
The dimensions and descriptions of the present specimens agree well with those provided by Raski (1975).

Paratylenchus longicaudatus Raski 1975
Dimensions: Refer Table 1 Description: Female: Body curved ventrally upon fixation more towards posterior region of vulva.Cuticle with fine transverse annulations.Body gradually narrows at anterior end to head which is conoid and truncate.Lip region rounded with indistinct annules.Lateral fields with four incisures.Stylet slender with slightly posteriorly directed knobs.Orifice of dorsal oesophageal gland located at 5.4±0.4(5-6) µm from stylet base.Median oesophageal bulb located at 63-88% of total oesophageal length.Nerve ring at 77.6±1.8 (75-80) µm from anterior end of body encircling the isthmus region.Cardia round, distinct.
Reproductive system mono-prodelphic and outstretched.Spermatheca oval shaped, with small spermatozoa.Vulval flaps large and rounded.Tail tapering to a finely rounded terminus.
Male: Not found.

Habitat and localities
Soil round roots of Cynodon dactylon (L) Urban from Lamka, Churachandpur District.

Remarks
The dimensions and morphological characters of the present populations correspond well with type specimen described by Raski (1975).

Description
Female: Body ventrally curved when relaxed, tapering at both ends but become swollen in pre-vulval region.Lateral field with three lines.Lip continuous with body contour, bluntly rounded, not setoff, almost hemispherical, with a slightly sloping side and a distinct depression at the oral apperture.Body cuticle marked by fine striae, nearly 1µm apart.Stylet slender with stout prominent knobs, which are backwardly directed.Excretory pore situated in the anterior region of basal bulb of the oesophagus.Oesophagus typical of the genus.Cardia small and rounded, about 4.2 ±0.3 (3.4-5) µm long.
Reproductive system mono-prodelphic, ovary outstretched with a single row.Spermatheca almost spherical and filled with small spermatozoa.Vulva, a transverse slit with  prominently rounded lateral vulvar membrane.Tail tip curved gently ventrad, conoid, narrows gradually to a bluntly rounded terminus.
Male: Body gently ventrally arcuate after fixation.Body narrows at anterior end to a rounded head at terminus and posterior from the region of the cloaca to an acute terminus.Head sloping with fine annule and sclerotization very light.Stylet lacking.Oesophagus degenerated.
Excretory pore distinct, near the nerve ring.Lateral field with three lines.Body annules very fine.Testis full of large refractive spermatozoa.Anal sheath prominent and short.Spicule curved slightly.Tail straight, narrows to give a very slender conoid outline with an acute terminus.

Diagnosis and relationships
Paratylenchus thysanolus sp.nov. is distinct in having smaller body, bluntly rounded lip with a distinct depression at the oral aperture and heterogeneous tail shape in between male and female.The new species comes close to P. variatus Jairajpuri, 1982 andP. colbrani Raski, 1975.From P. variatus, it differs in the body length, stylet length, oesophagus length and shape