Echinodon meaning "hedgehog tooth" in reference to the spines on its teeth (Greek

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 echinos = hedgehog + odous = tooth), occasionally known as Saurechinodon, is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of small 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...

an dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 of the early Cretaceous

Cretaceous

The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 Period (Berriasian

Berriasian

In the geological timescale, the Berriasian is an age or stage of the Early or Lower Creteceous. It is the oldest or lowest subdivision in the entire Cretaceous. It spanned between 145.5 ± 4.0 Ma and 140.2 ± 3.0 Ma...

 age), 140 million years ago.

Discovery and species

The type specimen was discovered by Samuel Beckles

Samuel Beckles

Samuel H. Beckles was an English 19th century dinosaur hunter, who collected remains in Sussex and the Isle of Wight. In 1854 he described bird-like trackways that he thought could have been made by dinosaurs, which he later identified as probably those of an Iguanodon in 1862...

 in the Purbeck Beds near Swanage

Swanage

Swanage is a coastal town and civil parish in the south east of Dorset, England. It is situated at the eastern end of the Isle of Purbeck, approximately 10 km south of Poole and 40 km east of Dorchester. The parish has a population of 10,124 . Nearby are Ballard Down and Old Harry Rocks,...

, 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...

. A bipedal herbivore

Herbivore

Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

, it was around 60 centimetres (2 ft) long. Unlike most ornithischians, Echinodon had one or two caniniform teeth in each maxilla.

The only species is E. becklesii, named in 1861 by Richard Owen

Richard Owen

Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...

, who mistook it for a lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

. Remains of an Echinodon-like animal were found in stratigraphic zone 4 of the Morrison Formation. These are now named Fruitadens

Fruitadens

Fruitadens is a genus of heterodontosaurid dinosaur. The name means "Fruita tooth", in reference to Fruita, Colorado , where its fossils were first found. It is known from partial skulls and skeletons from at least four individuals of differing biological ages, found in Tithonian rocks of the...

.

Classification

Echinodon has at times been considered it a basal

Basal (phylogenetics)

In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 thyreophora

Thyreophora

The Thyreophora were a subgroup of the ornithischian dinosaurs...

n, mainly due to the erroneous association of 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...

 limb osteoderm

Osteoderm

Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...

s with its remains. Paul Sereno

Paul Sereno

Paul Callistus Sereno is an American paleontologist from the University of Chicago who discovered several new dinosaur species on several continents. He has conducted excavations at sites as varied as Inner Mongolia, Argentina, Morocco, and Niger...

's reclassification to Heterodontosauridae in 1991 remains somewhat controversial. David B. Norman

David B. Norman

David Bruce Norman is a British paleontologist, currently Director of the Sedgwick Museum, Cambridge University. He is a fellow at Christ's College, Cambridge where he teaches geology in the Natural Sciences tripos. He is a member of the Palaeontological Association. He has studied Iguanodon...

 and Paul M. Barrett redescribed Echinodon in 2002 and supported the heterodontosaurid classification, though using somewhat different evidence than Sereno.