What is porphyrin pigment and why it is present in earthworm?

Dear student,Porphyrins are a group of heterocyclic macrocycle organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges. The parent porphyrin is porphine, a rare chemical compound of exclusively theoretical interest. Substituted porphines are called porphyrins.The function of Porphyrin pigment in earthworm is to protect the body from getting injured by the harmful ultra violet rays.The color of the earthworm is dark-brown because of the presence of porphyrin pigment.Regards.