Question

What are pedipalps, and how would you describe their appearance?

Answer 1

Hint: Pedipalps are the pair of appendages found in a group of arthropods and used for capturing or holding prey. Their structure varies between different organisms.

Complete answer:
Pedipalps also called the palps or palpi, are segmented paired appendages found in the subphylum- Chelicerates of the Class Arachnida and Phylum Arthropoda. They are commonly found in the animals- spiders, horseshoe crabs, scorpion, sea spiders. They act as the second pair of appendages and are attached to the arthropods on the cephalothorax. Their position is defined as anterior to the walking legs and posteriorly to the jaws. They lie near the mouth. They function as an organ of touch and are modified to act as secondary sexual organs or for crushing or cutting food. They are also modified to hold and capture the prey for the animal. They also help in the delivery of sperms and help in the courtship delays for a few spiders and scorpions. Scorpions also use the pedipalps for burrow excavation. They are also used for facilitating the feeding purpose.

The coxa, the trochanter, the short patella, the femur, the tibia, and the tarsus are the six parts of the pedipalps. Their physical appearance differs in various organisms and can be nicely studied for the spiders and scorpions.
In spiders- the pedipalps are long and resemble walking legs and are present at their front side. They have the same segmentation as legs. Although they show a difference in the tarsus, it is undivided. Its segment coxa is modified to form a feeding structure. It is modified in males to carry sperm and modified in females to function as a sense organ. They are also used for holding and capturing prey or food.

In scorpions- the pedipalps form a chelate. They end at the two pincers found on the head of the scorpion. They occur in the second segment of the three-segmented scorpion. They are modified for capturing prey, holding food, or borrowing excavation.

Note: The second antennae in the crustacean insects are identified as a homologous organ of the pedipalps.
The pedipalps are often confused with Chelicerae in scorpions that are present in the front of their mouth and are modified to form pine-like claws. They remain inconspicuous behind the pedipalps in the scorpions.