''Obamadon'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

polyglyphanodontia Polyglyphanodontia, also known as the Borioteiioidea, is an extinct clade of lizards from the Cretaceous that includes around a dozen genera. Polyglyphanodontians were the dominant group of lizards in North America and Asia during the Late Cretac ...

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

s from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

of North America. Fossils have been found in the Hell Creek Formation of

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

and the Lance Formation of

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

. Researchers describe it as being distinguished by its "tall, slender teeth with large central cusps separated from small accessory cusps by lingual grooves." The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

was named ''Obamadon gracilis'' after United States president

Barack Obama Barack Hussein Obama II ( ; born August 4, 1961) is an American politician who served as the 44th president of the United States from 2009 to 2017. A member of the Democratic Party, Obama was the first African-American president of the U ...

, "in reference to the tall, straight teeth, and the manner in which Mr. Obama has acted as a role model of good oral hygiene for the world." According to Nicholas R. Longrich of

Yale University Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the wo ...

, the species "was probably a foot long, ndwith these tall, slender teeth it used to eat insects and plant matter." The lizard was identified as part of a search of museum collections to find snake and lizard species that had lived immediately prior to the

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...

, in which the

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s (with the exception of

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s) died out. Its identification was published by Longrich, Bhullar and Gauthier in a paper titled "Mass extinction of lizards and snakes at the Cretaceous–Paleogene boundary", published on December 10, 2012 in ''Proceedings of the National Academy of Sciences''. The scientists found that lizards and snakes had been more badly hit by the mass extinction than previously thought, with 83 percent of species – including ''Obamadon'' – dying out. All present-day species of lizards are descended from members of the surviving 17 percent.

Etymology

''Obamadon'' is not the first organism to be named after U.S. President Barack Obama. Other researchers have given his name to ''

Etheostoma obama ''Etheostoma obama'', the spangled darter, is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the east ...

'', the spangled darter or "Obamafish", and the lichen ''

Caloplaca obamae ''Caloplaca obamae'' is a species of crustose lichen in the fungus genus ''Caloplaca''. It is the first species to be named in honor of United States President Barack Obama. ''C. obamae'' was discovered in 2007 by Kerry Knudsen on Santa Rosa ...

''. Longrich denied any political intent in the nomenclature, telling ''

Politico ''Politico'' (stylized in all caps), known originally as ''The Politico'', is an American, German-owned political journalism newspaper company based in Arlington County, Virginia, that covers politics and policy in the United States and intern ...

'' that "we're just having fun with taxonomy", but commented that if the

2012 United States Presidential election The 2012 United States presidential election was the 57th quadrennial presidential election, held on Tuesday, November 6, 2012. Incumbent Democratic President Barack Obama and his running mate, incumbent Vice President Joe Biden, were re-el ...

had gone a different way he probably would not have used the name, as "it might have seemed like we were mocking it, naming a lizard that goes extinct after that, seemed kind of cruel." According to Longrich, he came up with the idea after the 2008 election: "when everything was all hope-y and change-y, we said we should name a dinosaur after him and call it the Obamadon." The holotype of this taxon was documented in the original 2012 paper but not explicitly identified in the text, which meant that ''Obamadon'' was not validly named in the 2012 paper. It was designated in the correction published in 2013, validating ''Obamadon''.

Description

''Obamadon'' is known from two lower jaw fragments, each less than a centimeter in length. One was found in the collections of the University of California Museum of Paleontology after having been collected from the Hell Creek Formation in Montana, and the other collected from the Lance Formation in Wyoming. When it was first named in 2012, ''Obamadon'' was identified as a member of the extinct group Polyglyphanodontia on the basis of a V-shaped connection between the two halves of the lower jaw, a slot-and-ridge type connection between the

dentary bone In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

of the lower jaw and another missing bone called the splenial bone, and teeth that are implanted within the jaw bone. Its jaw is thin and straight, unlike the curved jaws of most other polyglyphanodontians. ''Obamadon'' is estimated to have been about 30 cm (1 foot) in length and may have preyed on insects.Campbell, Hank
Obamadon Gracilis - Toothy Lizard Named After American President
''Science 2.0'', October 12, 2012, Retrieved 2012-12-13

Classification

''Obamadon'' is a primitive member of Polyglyphanodontia, a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

of lizards that became extinct after the Cretaceous–Paleogene extinction event. Its jaw material was once assigned to '' Leptochamops'', a more

derived Derive may refer to: * Derive (computer algebra system), a commercial system made by Texas Instruments * ''Dérive'' (magazine), an Austrian science magazine on urbanism *Dérive, a psychogeographical concept See also * *Derivation (disambiguatio ...

genus of polyglyphanodontian.

References

External links

Illustration of ''Obamadon'' (the small blueish lizard in the foreground) with other Cretaceous lizards and dinosaurs
{{Taxonbar, from=Q864301 Scincogekkonomorpha Prehistoric reptile genera Late Cretaceous lepidosaurs of North America Maastrichtian life Hell Creek fauna Paleontology in Wyoming Fossil taxa described in 2013 Species named after Barack Obama