Which of the following is the pigmentary material for iridophores?

Correct option is B

Correct Answer: (b) Guanine
Explanation:
→ Iridophores contain crystalline platelets of guanine, which reflect light and produce iridescent colors.
→ These structural colors are responsible for silvery, metallic, and rainbow-like appearances in fishes.
→ Iridophores function via light reflection rather than pigment absorption.
Information Booster:
→ Important in camouflage through counter-shading.
→ High density of guanine crystals enhances visibility or concealment.
→ Structural coloration also aids in communication and mating displays.
Additional Information (Other Options):
(a) Melanin – melanophores.
(c) Carotenoid – xanthophores.
(d) Pterin – pteridines found in erythrophores.