Tag: scale

In most biological nomenclature, a scale (Greek λέπιδ lepid, Latin squama) is a small rigid plate that grows out of an animal’s skin to provide protection. In lepidopteran (butterfly and moth) species, scales are plates on the surface of the insect wing, and provide coloration. Scales are quite common and have evolved multiple times with varying structure and function.
Scales are generally classified as part of an organism’s integumentary system. There are various types of scales according to shape and to class of animal.
Fish scales are dermally derived, specifically in the mesoderm. This fact distinguishes them from reptile scales paleontologically. Genetically, the same genes involved in tooth and hair development in mammals are also involved in scale development.
True cosmoid scales can only be found on the extinct Crossopterygians. The inner layer of the scale is made of lamellar bone. On top of this lies a layer of spongy or vascular bone and then a layer of dentine-like…