Echinodon

Echinodon (pronounced eh-KY-no-don) meaning "hedgehog tooth" in reference to the spines on its teeth (Ancient Greek: εχινος, romanizedechinos, lit. 'hedgehog', + ὀδών, odṓn, 'tooth'), occasionally known as Saurechinodon, is a genus of small European dinosaur of the early Cretaceous Period (Berriasian age), 140 million years ago.

Echinodon
Temporal range: Early Cretaceous, 140 Ma
Echinodon becklesii
Specimen NHMUK 48215b
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Family: Heterodontosauridae
Genus: Echinodon
Owen, 1861
Species:
E. becklesii
Binomial name
Echinodon becklesii
Owen, 1861
Synonyms

Saurechinodon

Discovery and species

Echinodon
Teeth and jaw fragments referred to Echinodon
Nuthetes and Echinodon
Echinodon being attacked by a Nuthetes hypothetically restored as a dromaeosaur

The type specimen was discovered by Samuel Beckles in the Purbeck Beds near Swanage, England. A bipedal herbivore, it was around 60 centimetres (2 ft) long. Unlike most ornithischians, Echinodon had one or two caniniform teeth in each maxilla.[1]

The only species is E. becklesii, named in 1861 by Richard Owen, who mistook it for a lizard. Remains of an Echinodon-like animal were found in stratigraphic zone 4 of the Morrison Formation.[2] These are now named Fruitadens.[3]

Classification

Echinodon has at times been considered a basal thyreophoran, mainly due to the erroneous association of turtle limb osteoderms with its remains. Paul Sereno's reclassification to Heterodontosauridae in 1991 remains somewhat controversial. David B. Norman and Paul M. Barrett redescribed Echinodon in 2002 and supported the heterodontosaurid classification, though using somewhat different evidence than Sereno.

The cladogram below follows the analysis by Butler et al., 2011:[4]

Heterodontosauridae

Echinodon

Abrictosaurus

NHM RU A100

Heterodontosaurus

Lycorhinus

Fruitadens

Tianyulong

References

  1. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 135. ISBN 1-84028-152-9.
  2. ^ Foster, J. (2007). "Appendix." Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. pp. 327-329.
  3. ^ Butler, Richard J.; Galton, Peter M.; Porro, Laura B.; Chiappe, Luis M.; Henderson, D. M.; Erickson, Gregory M. (2009). "Lower limits of ornithischian dinosaur body size inferred from a new Upper Jurassic heterodontosaurid from North America" (PDF). Proceedings of the Royal Society B. 277 (1680): 375–81. doi:10.1098/rspb.2009.1494. PMC 2842649. PMID 19846460.
  4. ^ Richard J. Butler; Jin Liyong; Chen Jun; Pascal Godefroit (2011). "The postcranial osteology and phylogenetic position of the small ornithischian dinosaur Changchunsaurus parvus from the Quantou Formation (Cretaceous: Aptian–Cenomanian) of Jilin Province, north-eastern China". Palaeontology. 54 (3): 667–683. doi:10.1111/j.1475-4983.2011.01046.x.
  • Norman D, Barrett P (2002). "Ornithischian dinosaurs from the Lower Cretaceous (Berriasian) of England". Special Papers in Palaeontology. 68: 161–189.
1861 in paleontology

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1861.

Averostra

Averostra, or "bird snouts", is a clade that includes most theropod dinosaurs that have a promaxillary fenestra (fenestra promaxillaris), an extra opening in the front outer side of the maxilla, the bone that makes up the upper jaw. Two groups of averostrans, the Ceratosauria and the Orionides, survived into the Cretaceous period. When the Cretaceous–Paleogene extinction event occurred, ceratosaurians and two groups of orionideans within the clade Coelurosauria, the Tyrannosauroidea and Maniraptoriformes, were still extant. Only one subgroup of maniraptoriformes, Aves, survived the extinction event and persisted to the present day.

Avetheropoda

Avetheropoda, or "bird theropods", is a clade that includes carnosaurians and coelurosaurs to the exclusion of other dinosaurs.

Berriasian

In the geological timescale, the Berriasian is an age or stage of the Early Cretaceous. It is the oldest, or lowest, subdivision in the entire Cretaceous. It spanned the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic) and precedes the Valanginian.

Cerapoda

Cerapoda ("ceratopsians and ornithopods") is a clade of the dinosaur order Ornithischia.

Dinosauriformes

Dinosauriformes is a clade of archosaurian reptiles that include the dinosaurs and their most immediate relatives. All dinosauriformes are distinguished by several features, such as shortened forelimbs and a partially to fully perforated acetabulum, the hole in the hip socket traditionally used to define dinosaurs. The oldest known member is Asilisaurus, dating to about 245 million years ago in the Anisian age of the middle Triassic period.

Fruitadens

Fruitadens is a genus of heterodontosaurid dinosaur. The name means "Fruita tooth", in reference to Fruita, Colorado (USA), 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 (Late Jurassic) rocks of the Morrison Formation in Colorado. Fruitadens is the smallest known ornithischian dinosaur, with young adults estimated at 65 to 75 cm (26 to 30 in) in length and 0.5 to 0.75 kg (1.1 to 1.7 lb) in weight. It is interpreted as an omnivore and represents one of the latest-surviving heterodontosaurids.

Haya griva

Haya is an extinct genus of basal neornithischian dinosaur known from Mongolia.

Heterodontosauridae

Heterodontosauridae is a family of early ornithischian dinosaurs that were likely among the most basal (primitive) members of the group. Although their fossils are relatively rare and their group small in numbers, they lived across all continents except Australia for approximately 100 million years, from the Late Triassic to the Early Cretaceous.

Heterodontosaurids were fox-sized dinosaurs less than 2 metres (6.6 feet) in length, including a long tail. They are known mainly for their characteristic teeth, including enlarged canine-like tusks and cheek teeth adapted for chewing, analogous to those of Cretaceous hadrosaurids. Their diet was herbivorous or possibly omnivorous.

Heterodontosaurinae

Heterodontosaurinae is an extinct subfamily of heterodontosaurid ornithischian dinosaurs from the earliest to the mid Middle Jurassic (Hettangian - Bajocian) of Africa and South America. Currently, the basalmost known heterodontosaurine is Lycorhinus angustidens from the Early Jurassic of Cape Province, South Africa. Heterodontosaurines are small-bodied ornithischians characterized by their cheek tooth crowns that are taller than wide, and jaw joint set below the axis of occlusion between maxillary and dentary teeth. Heterodontosaurinae was implicitly named in 1966 by Oskar Kuhn as he is the author of the family Heterodontosauridae. It is a stem-based taxon defined phylogenetically for the first time by Paul Sereno in 2012 as "the most inclusive clade containing Heterodontosaurus tucki Crompton and Charig 1962 but not Tianyulong confuciusi Zheng et al. 2009, Fruitadens haagarorum Butler et al. 2010, Echinodon becklesii Owen 1861."

Jeholosauridae

Jeholosaurids were herbivorous neornithischian dinosaurs from the Cretaceous Period (Aptian - Santonian, with a possible Campanian record) of Asia. The family was first proposed by Han et al. in 2012. The jeholosaurids were defined as those ornithischians more closely related to Jeholosaurus shangyuanensis than to Hypsilophodon foxii, Iguanodon bernissartensis, Protoceratops andrewsi, Pachycephalosaurus wyomingensis, or Thescelosaurus neglectus. The Jeholosauridae includes the type genus Jeholosaurus and Yueosaurus.

Jingshanosaurus

Jingshanosaurus (meaning "Jingshan lizard") is a genus of sauropodomorph dinosaurs from the early Jurassic period.

Manidens

Manidens is a genus of heterodontosaurid dinosaur from the Middle Jurassic of Patagonia. Fossils have been found in the Cañadón Asfalto Formation in Chubut Province, Argentina, dating to the Bajocian.

Neotheropoda

Neotheropoda (meaning "new theropods") is a clade that includes coelophysoids and more advanced theropod dinosaurs, and the only group of theropods who survived the Triassic–Jurassic extinction event. Yet all of the neotheropods became extinct during the early Jurassic period except for Averostra.

Orionides

Orionides is a clade of tetanuran theropod dinosaurs from the Middle Jurassic to the Present. The clade includes most theropod dinosaurs, including birds.

Portland stone

Portland stone or Portland Stone Formation is a limestone formation from the Tithonian stage of the Jurassic period quarried on the Isle of Portland, Dorset. The quarries are cut in beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles, notably in major public buildings in London such as St Paul's Cathedral and Buckingham Palace. Portland stone is also exported to many countries—being used for example in the United Nations headquarters building in New York City.

Riojasauridae

Riojasauridae is a family of sauropod-like dinosaurs from the Upper Triassic. It is known primarily from the genera Riojasaurus and Eucnemesaurus. Sites containing Riojasauridae include the Lower Elliot Formation of Orange Free State, South Africa (where fossils of Eucnemesaurus have been found), and Ischigualasto, in La Rioja Province, Argentina ( where fossils of Riojasaurus have been recovered).

Samuel Beckles

Samuel Husbands Beckles (12 April 1814 in Barbados – 4 September 1890 in Hastings) was a Bajan/English 19th-century lawyer, turned 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 Iguanodon in 1862. In 1857, following the discovery of a mammal jaw at Durlston Bay, he directed a major excavation that became known as 'Beckles' Pit', removing five metres of overburden over a 600 square metre area, one of the largest ever scientific excavations. The collection of mammal fossils that resulted is now mainly held at the Natural History Museum. He discovered the small herbivorous dinosaur Echinodon. The only known species Echinodon becklesii, the mammal Plagiaulax becklesii and the dinosaur Becklespinax were named in his honour.

Tianyulong

Tianyulong (Chinese: 天宇龍; Pinyin: tiānyǔlóng; named for the Shandong Tianyu Museum of Nature where the holotype fossil is housed) was a genus of heterodontosaurid ornithischian dinosaur. The only species was T. confuciusi, whose remains were discovered in Jianchang County, Western Liaoning Province, China.

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