Dapedium is an extinct genus of primitive neopterygian

Neopterygii

Neopterygii is a group of Actinopteri animals. Neopterygii means "new fins". There are only few changes during their evolution from the earlier actinopterygians. They appeared somewhere in the Late Permian, before the time of the dinosaurs. The Neopterygii is a very successful group of fishes,...

 ray-finned fish. The first-described finding was an example of D. politum, found in the Lower Lias

Lias

Lias may refer to:*In geology:**The Lias Group, a group in the stratigraphy of Great Britain, formed during the Late Triassic to Early Jurassic epochs. It includes the Blue Lias and White Lias...

 of Lyme Regis

Lyme Regis

Lyme Regis is a coastal town in West Dorset, England, situated 25 miles west of Dorchester and east of Exeter. The town lies in Lyme Bay, on the English Channel coast at the Dorset-Devon border...

, on the Jurassic Coast

Jurassic Coast

The Jurassic Coast is a World Heritage Site on the English Channel coast of southern England. The site stretches from Orcombe Point near Exmouth in East Devon to Old Harry Rocks near Swanage in East Dorset, a distance of ....

 of England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 (Leach

William Elford Leach

William Elford Leach FRS was an English zoologist and marine biologist.Leach was born at Hoe Gate, Plymouth, the son of a solicitor. At the age of twelve he went to school in Exeter, studying anatomy and chemistry. By this time he was already collecting marine samples from Plymouth Sound and along...

 1822). Dapedium lived in the late 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...

 and Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

 periods.

Appearance

The various species of Dapedium ranged from 9 to 40 cm (3.5 to 15.7 ) long, and all had an oval to near-circular body. The skin was covered with thick, rhomboid, ganoid (enamel-like) scales. The smallest species so far found is D. noricum.

The skull was armoured with bony dermal plates, which were especially plentiful in the orbital

Orbit (anatomy)

In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...

 region. These bones bore irregular tubercles. The small pectoral and pelvic fins, along with the extended dorsal

Dorsal fin

A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 and anal fins formed a functional unit with the tail. The tail was short and stout, providing the power for a sudden change in direction while the fish was swimming.

The upper jaw of Dapedium was moveable and could protrude from the mouth, enabling a wider gape to capture larger prey.

Distribution

Dapedium lived mostly in the Jurassic seas of Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, a peripheral continental shelf sea of the Tethys Ocean

Tethys Ocean

The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...

. Notable finds have been made in Holzmaden

Holzmaden

Holzmaden is a town in Baden-Württemberg, Germany that lies between Stuttgart and Ulm.The ground in and around the city contains rich layers of well preserved fossils of the Jurassic period. The fossils are found in the 160 million year old Posidonia Shale and displayed in the local Museum Hauff...

, 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 Temple Grafton

Temple Grafton

Temple Grafton is a village and civil parish in the Stratford district of Warwickshire, England, situated about east of Alcester and West of the county town of Warwick. The place name is misleading, the Knights Templar never having any association with the place but owing to a naming error made...

, Warwickshire

Warwickshire

Warwickshire is a landlocked non-metropolitan county in the West Midlands region of England. The county town is Warwick, although the largest town is Nuneaton. The county is famous for being the birthplace of William Shakespeare...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 and in Lyme Regis

Lyme Regis

Lyme Regis is a coastal town in West Dorset, England, situated 25 miles west of Dorchester and east of Exeter. The town lies in Lyme Bay, on the English Channel coast at the Dorset-Devon border...

, Dorset

Dorset

Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...

, England.

Behaviour

The strong and pointed dentition suggests that Dapedium was durophagous

Durophagy

Durophagy is the term for describing the eating behavior of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled mollusks, or crabs....

, feeding on hard-shelled invertebrates, like mussels and sea urchins.