Turtles - Antique scientific engraving - Ernst Haeckel, Kunstformen der Natur

Reproduction engraving of: Turtles

Original title Chelonia - Schildkröten

Poster of Testudo - Vertebrates of the class Reptiles, Suborder Chelonia (Chelonia)

Illustration from the book Kunstformen der Natur, which is a collection of artistic lithographs of natural sciences published by the German biologist Ernst Haeckel between 1899 and 1904.

This naturalistic illustration is part of an overall style inspired by Ernst Haeckel, which greatly influenced the emerging Art Nouveau movement at the beginning of the ^20th century. This work, illustrating the impressive beauty and great diversity of the biological world, was complemented by a certain amount of scientific information, some excerpts of which are reproduced below.

This information is over 120 years old and some of it may be outdated!

Scientific classification:

 Vertebrate Phylum (Vertebrata)
Main class Gnathostomes (Gnathostoma)
Class Reptiles (Reptilia)
Chelonian Legion (Chelonia).

Scientific notice (extract) accompanying the poster print of Chelonia - Turtles :

The distinctive group of turtles (Chelonia) is one of those specialties of the reptile class that have diverged considerably from the ancestral group of crocodile-like archosaurs, adapting to particular living conditions and habits. Unlike the elongated body of other reptiles, that of turtles is greatly shortened (similar to that of amphibians such as frogs and toads among amphibians). Their beak-like jaws are toothless. The main characteristic lies in the formation of a solid bony carapace that surrounds the large, broad, and short body. In the historical evolution of this carapace, made of dermal bones (similar to fish scales), two main stages can be distinguished: the ancient plate turtles (Atheconia) date back already to the Triassic period (with Psephoderma in the Djougar limestone), and to the Cretaceous period (with Protostega, among others); Today, only a single representative remains, the remarkable leatherback turtle (Dermatochelys, Fig. 1). The cutaneous skeleton of these Atheconia still resembles that of the ancient reptiles from which they descended (the Anomodontia and the archosaurs); it is composed of numerous small bones, either isolated or forming a set of plates. This cutaneous skeleton is still distinct from the internal bony skeleton. On the other hand, in the case of the second main group, the more recent armoured turtles (Thecophora), the numerous small bony plates of the skin join together to form an immobile bony carapace, which also fuses with the thoracic vertebrae and ribs. Only two large openings remain in this carapace: one at the front, allowing the mobile exit of the head and forelimbs, and one at the rear, for the passage of the tail and hindlimbs. The epidermis covering this cutaneous shell remains soft only in ancient chelonians (skinned turtles, Bursochelya); in more recent ones (horned turtles, Cerachelya), it becomes cornified to form the robust horny plates, technically called "scales", which are valued.

Species present on the naturalist board of Turtles - Testudo :

• Dermatochelys coriacea
• Caretta imbricata
• Hydromeda tectifera
• Chelys fimbriata
• Testudo geometrica
• Testudo elephantina
• Chelydra serpentina