Cyamodus was a placodont

Placodont

Placodonts were a group of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. It is believed that they were part of Sauropterygia, the group that includes Plesiosaurs...

, known from fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 remains discovered in Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, in the early-to-mid-19th century and was named by Christian Erich Hermann von Meyer

Christian Erich Hermann von Meyer

Christian Erich Hermann von Meyer was a German palaeontologist.He was born at Frankfurt am Main.In 1832 von Meyer issued a work entitled Palaeologica, and in course of time he published a series of memoirs on various fossil organic remains: molluscs, crustaceans, fishes and higher vertebrata,...

, in 1863. The fossils have been dated to the Triassic

Triassic

The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

 Period, from the Anisian

Anisian

In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 245 million years ago until 237 million years ago, approximately...

 to Ladinian

Ladinian

The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between 237 ± 2 Ma and 228 ± 2 Ma...

 stages. Cyamodus was 1.3 meters (4 feet) long.
Cyamodus was a heavily armored

Armour (zoology)

Armour in animals is external or superficial protection against attack by predators, formed as part of the body , usually through the hardening of body tissues, outgrowths or secretions. It has therefore mostly developed in 'prey' species...

 swimmer that fed mainly on shellfish

Shellfish

Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...

 that it was specialized to uproot and crush with its powerful jaw

Jaw

The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...

s. The body of Cyamodus, specifically the armor, has been described as possessing a turtle

Turtle

Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...

-like flatness. The shell was a two-part carapace

Carapace

A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...

 on the upper surface of the body. The larger half covered Cyamodus from the neck

Neck

The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

 to the hips

Hip (anatomy)

In vertebrate anatomy, hip refer to either an anatomical region or a joint.The hip region is located lateral to the gluteal region , inferior to the iliac crest, and overlying the greater trochanter of the femur, or "thigh bone"...

 and spread out flat, almost encompassing the limbs

Limb (anatomy)

A limb is a jointed, or prehensile , appendage of the human or other animal body....

. The second, smaller plate covered the hips and the base of the tail

Tail

The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...

. The shells themselves are covered in hexagonal or circular plates of armor. The skull

Skull

The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

 is heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

-shaped and broad.

Thus far, five species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

of Cyamodus have been identified - C. rostratus, C. munsteri, C. tarnowitzensis, C. hildegardis, and C. kuhnschneyderi.

Cyamodus is the type genus of the family Cyamodontidae.