Pigmentation of the marine isopod idothea granulosa (rathke)

Abstract

1. 1. Tissue and chromatophore pigments were isolated from the three color varieties of the marine isopod Idothea granulosa. These included β-carotene, isocryptoxanthin, echinenone, 4-hydroxy-4t́-keto-β-carotene, canthaxanthin, isozeaxanthin and lutein. 2. 2. The red, green and brown coloration of this species is primarily a result of the pigmentation of the epidermis although the animals' red chromatophores can effect a rapid change of color before epidermal pigments can be changed. 3. 3. The chromatophore pigment is a reduced ommochrome. 4. 4. The cuticles of all three color varieties contain two pigmented layers, the exocuticle and the endocutile. The oxocuticle is red and contains canthaxanthin and the endocuticle is yellow and contains lutein. 5. 5. Red animlas have canthaxanthin as their chief epidermal pigment. 6. 6. Green animlas have a green protein complex deposited in their epidermis. The complex appears to be a lipoprotein with strongly bound canthaxanthin and loosely bound or adsorbed lutein. 7. 7. Brown animlas have a mixture of the green complex and canthaxanthin in their epidermis. 8. 8. A possible pathway has been suggested for the production of canthaxanthin from β-carotene. 9. 9. A comparison has been made of the pigments and pigmentary systems in I. granulosa and I. montereyensis.