Question

Choose the incorrect combination among the following:

Class	Character	Example
1) Xiphosura	Poisonous Claws	Limulus
2) Arachnida	Coxal Glands	Scutigera
3) Crustacea	Biramous appendage	Sarcoptes
4) Diplopoda	Gnathochilarium	Spirostreptus

• A. 2, 3, 4
• B. 1, 3, 4
• C. 1, 2, 4
• D. 1, 2, 3

Hint:

Always match both anatomical features and correct taxonomic class with the correct organism to spot mismatches.

Answer 1

The Correct Option is D

Let’s analyze each combination:
- 1) Xiphosura – Poisonous Claws – Limulus:
Incorrect. Limulus (horseshoe crab) belongs to Xiphosura but does not possess poisonous claws. Poisonous claws are associated with centipedes, not horseshoe crabs.
- 2) Arachnida – Coxal Glands – Scutigera:
Incorrect. Coxal glands are indeed present in arachnids, but Scutigera (a centipede) belongs to Chilopoda, not Arachnida.
- 3) Crustacea – Biramous appendage – Sarcoptes:
Incorrect. Crustaceans do have biramous appendages, but Sarcoptes (a mite) is an arachnid, not a crustacean.
- 4) Diplopoda – Gnathochilarium – Spirostreptus:
Correct. Diplopods (millipedes) like Spirostreptus possess a gnathochilarium (a fused structure derived from mouthparts).
Thus, combinations 1, 2, and 3 are incorrect.

Answer 2

The incorrect combinations among the given options are 1, 2, and 3. Let's analyze each option in detail:

1) Xiphosura – Poisonous Claws – Limulus:
Xiphosura, represented by the horseshoe crab Limulus, do not possess poisonous claws. Instead, Limulus has chelicerae (claw-like appendages) used for feeding but these are not poisonous. Hence, this combination is incorrect.

2) Arachnida – Coxal Glands – Scutigera:
Arachnids generally do not have coxal glands; these are excretory structures found in some myriapods and crustaceans. Also, Scutigera is not an arachnid but belongs to the class Chilopoda (centipedes). Thus, this combination is wrong.

3) Crustacea – Biramous Appendage – Sarcoptes:
Crustaceans do have biramous appendages, but Sarcoptes is a genus of mites, which belong to the class Arachnida, not Crustacea. Therefore, this pairing is incorrect.

4) Diplopoda – Gnathochilarium – Spirostreptus:
Diplopoda (millipedes) have a gnathochilarium, a specialized mouthpart structure, and Spirostreptus is a valid example of a millipede. This combination is correct.

Thus, the incorrect combinations are 1, 2, and 3.