Spider are apparently absent. In some species, the exocuticle of the legs and prosoma is modified by a tanning process, resulting in brown coloration. Bilins are found, for example, in "Micrommata virescens", resulting in its green color. Guanine is responsible for the white markings of the European garden spider "Araneus diadematus". It is in many species accumulated in specialized cells called guanocytes. In genera such as "Tetragnatha", "Leucauge", "Argyrodes" or "Theridiosoma", guanine creates their silvery appearance. While guanine is originally an end-product of protein metabolism, its excretion can be blocked in spiders, leading to an increase in its storage. Structural colors
Iberian shrew juveniles, the fur is also adapted for cold, damp habitats: each guard hair possesses an indentation along its length that helps to prevent water from reaching the body. The skull of "S. granarius" can be used to distinguish it from other species belonging to the European "Sorex araneus" group of shrews. Comparatively, the snout of "S. granarius" is small and flat, the mandible possesses a diminished coronoid process and a narrow angular process, and the temporal fossa of the skull resembles a triangle. The "Sorex araneus" group of European shrews consists of "S. araneus", "S. coronatus", and "S. granarius", with