Question

Match List-I with List-II. List-I:
(A) Tylenchorhynchus
(B) Pratylenchus
(C) Hoplolaimus
(D) Zygotylenchus. List-II: (I) No marked sexual dimorphism in the anterior region, tails dissimilar between sexes; phasmids near the middle of tail, one functional ovary, vulva in posterior region at 70–80%, postvulval uterine sac present. (II) Generally large bodied, labial framework and stylet massive, stylet knobs anchor or tulip-shaped, phasmids enlarged to scutella, females diovarial, outstretched. (III) Body medium-sized, cephalic framework slight to heavily sclerotized, females diovarial, amphidelphic, ovaries outstretched, vulva about 50%, tail round. (IV) Body length under 1 mm, no sexual dimorphism of anterior body, lip region truncate, flattened anteriorly, esophago-intestinal valve not well developed, phasmids about mid-tail, female genital tract with two branches equally developed - didelphic, amphidelphic, tail tip cylindrical, rounded. Choose the correct answer from the options given below:

• A. (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
• B. (A)-(I), (B)-(IV), (C)-(II), (D)-(III)
• C. (A)-(III), (B)-(I), (C)-(II), (D)-(IV)
• D. (A)-(II), (B)-(IV), (C)-(I), (D)-(III)

Hint:

To solve this quickly, associate the genus Pratylenchus with its single ovary and posterior vulva (monovarial, 70-80% vulva), which is a key diagnostic feature that immediately identifies B-I.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Identifying plant-parasitic nematodes relies on a combination of morphological and anatomical features.
Key diagnostic traits include body size, the structure of the stylet and cephalic framework, the number and position of the ovaries (monovarial vs. diovarial), the location of the vulva, and the structure of the tail and phasmids.

Step 2: Detailed Explanation:
Let us analyze the unique characters of each nematode genus:
(A) Tylenchorhynchus (Stunt Nematode):
These are small nematodes (typically under 1 mm) with a lip region that is often truncate and flattened anteriorly.
They have a didelphic, amphidelphic female reproductive tract (two functional ovaries) with the vulva located near the middle of the body (around 50%).
The tail is cylindrical with a rounded tip, and the phasmids are located near the middle of the tail.
This matches description (IV).
(B) Pratylenchus (Lesion Nematode):
This genus is characterized by having a single functional ovary (monovarial, prodelphic) with the vulva located posteriorly (at 70-80% of body length).
They also have a postvulval uterine sac (PUS).
This matches description (I).
(C) Hoplolaimus (Lance Nematode):
These are relatively large-bodied, robust nematodes.
They have a heavily sclerotized cephalic framework and a massive stylet with tulip-shaped or anchor-shaped knobs.
Their phasmids are enlarged into circular structures called scutella, and they have two outstretched ovaries.
This matches description (II).
(D) Zygotylenchus:
This genus has a medium-sized body, a slightly to heavily sclerotized cephalic framework, two outstretched ovaries (didelphic, amphidelphic), and a vulva located near 50%.
The tail is typically rounded.
This matches description (III).
Combining these matches yields the sequence: (A) - (IV), (B) - (I), (C) - (II), (D) - (III).

Step 3: Final Answer:
The matching sequence is correctly represented by Option 1.