Question

Thin-walled, lamellate structures present on the coxal segment of each maxilliped in a typical prawn are called

• A. Protopodites
• B. Exopodites
• C. Endopodites
• D. Epipodites

Hint:

Remember the appendage outgrowth positions:
Endo- $\rightarrow$ inner ramus.
Exo- $\rightarrow$ outer ramus.
Epi- $\rightarrow$ outer outgrowth from the basal Coxa (Epipodite).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Crustacean appendages are typically biramous, consisting of basal segments that branch into inner and outer rami.
Specialized outgrowths on the basal segments serve respiratory, sensory, or cleaning functions.

Step 2: Detailed Explanation:
Let us define the morphological structures of a typical prawn limb (appendage):
Protopodite is the basal portion of the limb, which is attached to the body wall and consists of two segments: coxa and basis.
Endopodite is the inner branch or ramus arising from the protopodite.
Exopodite is the outer branch or ramus arising from the protopodite.
Epipodite is a thin-walled, lamellate, often vascularized outgrowth arising from the outer margin of the coxal segment of the protopodite.
In prawns and other decapod crustaceans, epipodites are present on the maxillipeds (mouthparts) and extend into the gill chamber.
These structures are thin-walled to facilitate gaseous exchange, serving as auxiliary respiratory structures or helping to ventilate and clean the gills.
Therefore, these thin-walled, lamellate coxal outgrowths are called epipodites.

Step 3: Final Answer:
The structures present on the coxal segment are called Epipodites.