Screwed up: Spirality of segments and other iterated structures suggest an underlying principle of seriality in bilaterians

This review deals with helicomery, that is, the specific malformation of a spiral arrangement segments and other serial structures. Helicomery was first described in annelid arthropod body segments. However, corresponding patterns occur appendages bilaterians serially arranged parts, such as tapeworms, nematodes, vertebrates, probably chitons. The specifics spirals length, orientation, handedness are described. Most dorsal comprise only few loops. is formed by shift cells during development or adults caused changes cell adhesion mechanical impacts lesions. A model for formation helicomery proposed, which based on medieval church labyrinths. These complex structures derived from concentric lines relatively tiles. principle “small causes, great effect” also applies to “spiral segments,” because dissolves segmental questions concept distinct widespread occurrence nonhomologous might indirectly indicate an underlying seriality among Bilateria.