Question

Match List-I with List-II

List-I (Shellfish)		List-II (Larval Stage)
A	Crab	I	Phyllosoma
B	Lobster	II	Zoea
C	Scampi	III	Glochidium
D	Freshwater mussel	IV	Megalopa

Choose the correct answer from the options given below:

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

Hint:

Use unique key stages for elimination: "Phyllosoma" is exclusively found in lobsters, and "Glochidium" is the classic parasitic larva of freshwater mussels. This immediately simplifies the matching process.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Shellfish, including crustaceans (crabs, lobsters, scampi) and molluscs (freshwater mussels), go through distinct planktonic larval stages during their life cycle before morphing into benthic adults.

Step 2: Detailed Explanation:
Let us match the shellfish to their respective larval stages:
- (A) Crab: Crabs hatch from eggs as zoea larvae, which eventually molt into the megalopa stage. The megalopa represents the final larval stage, characterized by prominent cheliped limbs and a partially folded abdomen, which is highly distinct for crabs. Thus, (A) matches with (IV).
- (B) Lobster: Spiny lobsters (Palinuridae) have a highly specialized, paper-thin, transparent, leaf-like planktonic larval stage known as the Phyllosoma larva. Thus, (B) matches with (I).
- (C) Scampi: Freshwater prawns (genus Macrobrachium) go through 11 distinct planktonic larval stages, hatching as zoea. Thus, (C) matches with (II).
- (D) Freshwater mussel: Freshwater bivalve molluscs produce a unique microscopic larval stage called the Glochidium larva, which has hooks to attach parasitically to the gills or fins of host fishes for its dispersal. Thus, (D) matches with (III).
Combining these pairs, we get: (A) - (IV), (B) - (I), (C) - (II), (D) - (III).

Step 4: Final Answer:
The correct matching sequence is (A) - (IV), (B) - (I), (C) - (II), (D) - (III), which corresponds to Option (A).