Phyllodon

Phyllodon (meaning "leaf tooth") was a genus of small ornithischian dinosaur from the Kimmeridgian-age Upper Jurassic Guimarota Formation of Leiria, Portugal. It may have been closely related to contemporaneous dinosaurs in North America.

This genus is known from teeth and possibly partial lower jaws. The name is also in use for a genus of modern moss, but this is not considered to be a problem because the two organisms are in two different kingdoms.

Phyllodon
Temporal range: Late Jurassic
Phyllodon
Tooth
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Clade: Neornithischia
Genus: Phyllodon
Thulborn, 1973
Species:
P. henkeli
Binomial name
Phyllodon henkeli
Thulborn, 1973

History

Phyllodon is based on MGSP G5, a partial lower jaw tooth recovered from a lignite marl in a mine near the city of Leiria. Richard Thulborn, who described the genus, added an upper beak tooth (MGSP G2). He regarded the new genus as a hypsilophodontid, and presented a conjectural restoration of the tooth arrangement.[1] Peter Galton, reviewing Late Jurassic North American hypsilophodontids a few years later, found that the Phyllodon teeth best matched those of Nanosaurus, and agreed with a hypsilophodontid identity because the lower jaw tooth is asymmetric in front and back views.[2]

Because of the sparse material, Phyllodon has often been tossed off as a dubious basal ornithopod of uncertain affinities.[3][4] However, more material that might belong to this genus has been recovered from the original locality and described. Included in this material are over 120 more teeth from all parts of the jaw and four partial lower jaws with the teeth lost. Oliver Rauhut, who described the new material, tentatively identified the lower jaws as Phyllodon due to there being no other similar dinosaurs found at the locality. The teeth were very small (up to 3 millimeters across, or 0.1 inches) and possibly juvenile. He also found additional diagnostic characteristics for Phyllodon in the new material, including very tall upper jaw teeth, indicating that it could be a valid genus after all. After comparing it to other hypsilophodonts, he found that it best matched the roughly contemporaneous Drinker of the North American Morrison Formation, with various details suggesting that they were closely related.[5] Similarly, Galton found its teeth to be similar to those of Drinker and Nanosaurus in his 2006 review.[6]

Paleobiology

As a hypsilophodontid or other basal ornithopod, Phyllodon would have been a bipedal herbivore. Its size has not been estimated, but as most adult hypsilophodonts were 1–2 meters (3.3–6.6 ft) long,[4] this genus would probably have been of similar size. Its similarity to the North American Drinker and Nanosaurus is another piece of evidence linking Late Jurassic Portuguese dinosaur faunas with the contemporaneous Morrison Formation dinosaurs.[7]

References

  1. ^ Thulborn, Richard A. (1973). "Teeth of ornithischian dinosaurs from the Upper Jurassic of Portugal, with description of a hypsilophodontid (Phyllodon henkeli gen. et sp. nov.) from the Guimarota lignite". Memória Serivoços Geológicos de Portugal (Nova Série). 22: 89–134.
  2. ^ Galton, Peter M. (1983). "The cranial anatomy of Dryosaurus, a hypsilophodontid dinosaur from the Upper Jurassic of North America and East Africa, with a review of hypsilophodontids from the Upper Jurassic of North America". Geologica et Palaeontologica. 17: 207–243.
  3. ^ Sues, Hans-Dieter; Norman, David B. (1990). "Hypsilophodontidae, Tenontosaurus, Dryosauridae". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (1st ed.). Berkeley: University of California Press. pp. 498–509. ISBN 0-520-06727-4.
  4. ^ a b Norman, David B.; Sues, Hans-Dieter; Witmer, Larry M.; Coria, Rodolfo A. (2004). "Basal Ornithopoda". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 393–412. ISBN 0-520-24209-2.
  5. ^ Rauhut, Oliver W.M. (2001). "Herbivorous dinosaurs from the Late Jurassic (Kimmeridgian) of Guimarota, Portugal". Proceedings of the Geologists' Association. 112 (3): 275–283. doi:10.1016/S0016-7878(01)80007-9.
  6. ^ Galton, Peter M. (2006). "Teeth of ornithischian dinosaurs (mostly Ornithopoda) from the Morrison Formation (Upper Jurassic) of the western United States". In Carpenter, Kenneth (ed.). Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Bloomington and Indianapolis: Indiana University Press. pp. 17–47. ISBN 0-253-34817-X.
  7. ^ Mateus, Octávio (2006). "Late Jurassic dinosaurs from the Morrison Formation (USA), the Lourinhã and Alcobaça Formations (Portugal), and the Tendaguru Beds (Tanzania): a comparison". In Foster, John R.; Lucas, Spencer G. (eds.). Paleontology and Geology of the Upper Morrison Formation. New Mexico Museum of Natural History and Science Bulletin (36). Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 223–231.
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.

Camadas de Guimarota

The Camadas de Guimarota, simply Guimarota, or Camadas de Alcobaça is a disused coal mine near the city of Leiria in central Portugal. An important geological formation dating back to the Kimmeridgian age of the Late Jurassic period, it contains a diverse array of fossil animals and plants, including dinosaurs and mammals.

The locality was extensively worked by paleontologists from the Free University of Berlin, but this activity stopped in 1982. Further excavations are considered to be unlikely, since the mine is now flooded. Pumping it out and rendering it safe again would be prohibitively expensive.

The mammal remains from this site are of particular note. The excavations were so successful that many of the recovered remains have yet to be studied.

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.

Haya griva

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

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.

Melanorosauridae

The Melanorosauridae were a family of sauropodomorph dinosaurs which lived during the Late Triassic and Early Jurassic. The name Melanorosauridae was first coined by Friedrich von Huene in 1929. Huene assigned several families of dinosaurs to the infraorder "Prosauropoda": the Anchisauridae, the Plateosauridae, the Thecodontosauridae, and the Melanorosauridae. Since then, these families have undergone numerous revisions. Galton and Upchurch (2004) considered Camelotia, Lessemsaurus, and Melanorosaurus members of the family Melanorosauridae. A more recent study by Yates (2007) indicates that the melanorosaurids were instead early sauropods.

Neornithischia

Neornithischia ("new ornithischians") is a clade of the dinosaur order Ornithischia. They are the sister group of the Thyreophora within the clade Genasauria. Neornithischians are united by having a thicker layer of asymmetrical enamel on the inside of their lower teeth. The teeth wore unevenly with chewing and developed sharp ridges that allowed neornithischians to break down tougher plant food than other dinosaurs. Neornithischians include a variety of basal forms historically known as "hypsilophodonts", including the Parksosauridae; in addition, there are derived forms classified in the groups Marginocephalia and Ornithopoda. The former includes clades Pachycephalosauria and Ceratopsia, while the latter typically includes Hypsilophodon and the more derived Iguanodontia.

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.

Orodrominae

Orodrominae is a subfamily of parksosaurid dinosaurs from the Cretaceous of North America and Asia.

Phyllodon (plant)

Phyllodon is a genus of moss.

Raeticodactylidae

Raeticodactylidae is a family of eudimorphodontoid eopterosaurian pterosaurs that lived in Switzerland during the Late Triassic. The family includes Caviramus, and the type genus Raeticodactylus, which are both known from the Kössen Formation, around 205 mya. Raeticodactylidae was first used in 2014 by Andres et al., as a group of all pterosaurs closer to Raeticodactylus than Eudimorphodon. The following phylogenetic analysis follows the topology of Andres et al. (2014).

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).

Unaysauridae

Unaysauridae is a family of basal sauropodomorphs from the Late Triassic of India and Brazil.

Xixiposaurus

Xixiposaurus is a genus of prosauropod dinosaur which existed in what is now Lower Lufeng Formation, China during the lower Jurassic period. It was first named by Sekiya Toru in 2010 and the type species is Xixiposaurus suni.

Yueosaurus

Yueosaurus is an extinct genus of basal ornithopod dinosaur known from Zhejiang Province, China.

Languages

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.