Figure 4: Retinal melanosomes in an extant fish eye.
From: Molecular preservation of the pigment melanin in fossil melanosomes
(a) Cryosection through an eyecup of a juvenile three-spined stickleback fish (Gasterosteus aculeatus) where the retinal pigment epithelium (RPE) occurs as dark, brownish tissue (mirror image of original photograph). The rectangle indicates the area shown in (b). Scale bar: 100 μm. (b) Close-up of the RPE in G. aculeatus. Note that elongate melanosomes primarily occur in the distal parts of the RPE, whereas the proximal parts chiefly contain sub-spherical to oblate melanosomes. Degradation and ultimate collapse of the RPE during the process of fossilization would result in a mixture of melanosome morphologies located on top of each other, as in the eye of FUM-N-2050. Scale bar: 10 μm.
