Professor Ryozo Fujii lost his battle with cancer on July 1, 2002, and thus his contribution here is posthumous. Were it not for his enthusiasm toward making the scientific community aware of the bases of blue coloration is fishes, this review may not have been written. We are grateful to his daughter, Sana Harada, for providing materials and preliminary drafts of manuscripts in preparation.
On the blue coloration of vertebrates†
Article first published online: 11 JAN 2007
Pigment Cell Research
Volume 20, Issue 1, pages 14–26, February 2007
How to Cite
Bagnara, J. T., Fernandez, P. J. and Fujii, R. (2007), On the blue coloration of vertebrates. Pigment Cell Research, 20: 14–26. doi: 10.1111/j.1600-0749.2006.00360.x
The essence of this review is derived from a mini-symposium, ‘The Blues Symposium’, presented at the XVIth International Pigment Cell Conference held in Anaheim, CA, USA, October 29 to November 3, 1996. It was organized by Joseph T. Bagnara and co-organized by Jean L. Bolognia and the late Yoshiaki Hori (to whom this review is dedicated). Other speakers were Craig Bohren, Ryozo Fujii, Philip J. Fernandez, Randall L. Morrison, and Walter C. Quevedo, Jr.
- Issue published online: 11 JAN 2007
- Article first published online: 11 JAN 2007
- Received 19 October 2006; revised and accepted for publication 23 November 2006
- blue color;
- green color;
Although the various vertebrate classes, from fishes to mammals are each distinctive, they possess many common features making it important to understand their comparative biology. One general feature that has long commanded interest is the integumental pigmentary system. Thus, much is known about particular pigment cells; however, the basis for some specific colors, such as blue, has escaped the scrutiny of the comparative approach. Regardless of Class, blue is almost always a structural color based upon incoherent or coherent scatter of blue wavelengths from the animal surface. The source of scatter may be intracellular or extra-cellular. A main intracellular scatterer is the surface of reflecting platelets of iridophores of lower vertebrates. Extra-cellular scatter is widespread and thought to occur from ordered dermal collagen arrays in primitive fishes, birds and mammals including humans. Among birds, feather structures provide major means for extra-cellular light scatter. There is only one known example of blue color deriving from a blue pigment found within a pigment cell. For amphibians, reptiles and birds, the scatter of blue wavelengths, together with the presence of yellow pigmentation, is fundamental for the expression of green coloration.