ISSN:
1432-0878
Keywords:
Scale formation
;
Mineralization
;
Epidermis
;
Cichlasoma octofasciatum, (Teleostei)
;
Hemichromis bimaculatus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The region between the epidermis and the surface of the overlapping part of scales has been studied in two cichlid teleosts using transmission electron microscopy. In a few specimens only, numerous mineralized spherules (∼1 μm in diameter) are observed in the loose dermis and at the scale surface, and form a large part of the superficial outer limiting layer of the scale. In the loose dermis (stratum laxum) and close to the scale surface spherules are either free or included in dermal cells. When free, they are dispersed in the extracellular matrix of the dermis, among the fibrils of anchoring bundles, and fused with the scale surface. When included in cell vacuoles, they lie close to the lamina densa and to the scale surface. Steps in the formation of the mineralized spherules are only seen in the lamina densa of the basement membrane. The spherules contain needle-like mineral crystals radially orientated and an organic matrix of stippled material and dense granules, some of which form concentric lines around the centre of the spherules. The results suggest that mineralized spherules form in the lamina densa and pass through the dermis to the scale surface in which they are incorporated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00221751
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