Tortoiseshell Tortoiseshell Tortoiseshell or tortoise shell is a material produced from the shells of the larger species of tortoise and turtle, mainly the hawksbill sea turtle, which is an endangered species largely because of its exploitation for the material. The large size, fine colour and unusual form of the hawksbill's scutes make it especially suitable. The distinctive patterning is referred to in names such as the tortoiseshell cat, several breeds of guinea pig, and the common names of several species of the butterfly genera "Nymphalis" and "Aglais", and some other uses. Tortoiseshell was widely used from ancient times in the West
Turtle shell from the sternum of the turtle. This fits well with the knowledge obtained through embryological studies, showing that changes in the pathways of rib development often result in malformation or loss of the plastron. This phenomenon occurs in turtle development, but instead of experiencing complete loss of the sternum the turtle body plan repurposes the bone into the form of the plastron. The discovery of an ancestral turtle fossil, "Pappochelys rosinae," provides additional clues as to how the plastron formed. "Pappochelys" serves as an intermediate form between two early stem-turtles, "E. africanus" and "Odontochelys," the latter of which possesses a