Cosminecovered

Cosminecovered is a term used in paleontology and comparative anatomy to describe surfaces, typically dermal scales or denticles, that are coated with cosmine tissue. Cosmine is a specialized form of dentine found in the scales and teeth of certain early fishes and some extinct vertebrates. It forms a laminated, tubule-rich outer layer that can give the surface a distinctive wrinkle or pitted texture. In many cosmoid scales, the cosmine layer covers a vascular dentine core and is capped by an enamel-like material such as ganoine, producing a composite protective covering.

In the cosmoid arrangement, the cosmine-covered surface is characteristic of certain primitive dermal skeletons in sarcopterygian fishes, including early lungfishes and related Paleozoic taxa. Describing a surface as cosminecovered helps distinguish cosmoid scales from other dermal scale types such as elasmoid or placoid.

Researchers study cosmine-covered structures using light microscopy, scanning electron microscopy, and thin-section analysis to resolve tissue organization, growth lines, and tubule patterns. The concept contributes to understanding the evolution of dermal skeletons in early vertebrates and informs taxonomic and functional interpretations.