# Polyodontosaurus > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Polyodontosaurus > Markdown URL: https://mediated.wiki/source/Polyodontosaurus.md > Source: https://en.wikipedia.org/wiki/Polyodontosaurus > Source revision: 1324489454 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Genus of troodontid dinosaur from the Late Cretaceous period}} {{Speciesbox |fossil_range = [Campanian](/source/Campanian), {{fossilrange|75.5}} |image = |image_caption = |genus = Polyodontosaurus |parent_authority = [Gilmore](/source/Charles_W._Gilmore), [1932](/source/1932_in_paleontology) |species = grandis |authority = Gilmore, 1932 | synonyms = *''Polydontosaurus'' van der Reest & [Currie](/source/Phil_Currie), [2017](/source/2017_in_archosaur_paleontology) (''[sic](/source/sic)'') }} '''''Polyodontosaurus''''' (meaning "many-toothed lizard") is a potentially [dubious](/source/Nomen_dubium) [genus](/source/genus) of [troodontid](/source/troodontid) dinosaur named in 1932 by [Charles W. Gilmore](/source/Charles_W._Gilmore) for a left dentary from the [Dinosaur Park Formation](/source/Dinosaur_Park_Formation).[Gilmore, C. W.](/source/Charles_W._Gilmore) (1932). A new fossil lizard from the [Belly River Formation](/source/Belly_River_Formation) of Alberta. ''Transactions of the Royal Society of Canada'', section 4, series 3 16:117-119 It had been considered a synonym of ''[Stenonychosaurus](/source/Stenonychosaurus)'' or ''[Troodon](/source/Troodon)'' for a significant time, before being declared a ''[nomen dubium](/source/nomen_dubium)''. The only known species is the type, '''''P. grandis'''''. ==History of discovery== The [holotype](/source/holotype) and only known specimen of ''Polyodontosaurus'' was collected in 1928 by [Charles Mortram Sternberg](/source/Charles_Mortram_Sternberg), and includes only a left [dentary](/source/dentary), lacking any teeth. Sternberg presented the dentary to [Charles Gilmore](/source/Charles_W._Gilmore), who identified it as a lizard. Gilmore thus named the binomial ''Polyodontosaurus grandis'' for the new taxon in 1932. Sternberg revisited the material in 1951 and determined that it represented a carnivorous dinosaur based on the general morphology of the bone, as well as the anatomy of the Meckelian groove, multiple nutrient foramina, and separation of teeth into multiple sockets. Sternberg compared this dentary to one referred to ''[Troodon](/source/Troodon)'' by Russel in 1948, and decided that they belonged to the same family, and potentially the same genus. While similar, there were a few differences, that might be shown to relate to age or variation within the genus. Sternberg, therefore, referred ''Polyodontosaurus'' to the family Troodontidae, until further material could be found. The name ''Polyodontosaurus'' has been misspelled as "Polydontosaurus" by some authors. ''Polyodontosaurus'', represented by the holotype CMN 8540, was found in the Steveville area in the [Dinosaur Park Formation](/source/Dinosaur_Park_Formation). It was found about {{convert|37|m|ft|abbr=on}} below the highest layer of the formation, and comes from the MAZ (Megaherbivore assemblage zone)-2 portion of the fauna, which existed after MAZ-1. This exact stratigraphic location cannot be verified. MAZ-2 spans from 75.9 to 75.3 million years ago, CMN 8540 is from slightly above (younger) than the middle of the formation. In 1969 [Dale Russell](/source/Dale_Russell) described a new specimen of ''[Stenonychosaurus](/source/Stenonychosaurus)'', a troodontid closely related to ''[Saurornithoides](/source/Saurornithoides)''. This specimen, CMN 12340, was from the [Oldman Formation](/source/Oldman_Formation) of Alberta, which lies directly above the Dinosaur Park Formation. This specimen was later named ''[Latenivenatrix](/source/Latenivenatrix)'' and comes from the MAZ-2 level of the formation. Because of the similarities between ''Polyodontosaurus'', ''Stenonychosaurus'', and more complete ''Saurornithoides'', Russell concluded that ''Polyodontosaurus'' was a junior synonym of ''Stenonychosaurus'', and that they both might be synonyms of the tooth-taxon ''Troodon'', although the material of ''Troodon'' is very incomplete. ==Classification== After being initially named as a lizard, ''Polydontosaurus'' was reclassified as a troodontid, a classification which stands today. Since 1969 ''Polyodontosaurus'' has been considered a synonym of ''Stenonychosaurus'', and later its senior synonym ''Troodon''. ''Polyodontosaurus'' is potentially a synonym of the taxon ''Latenivenatrix'', named in 2017, but they may come from separate regions of the formation. Van der Reest & Currie in 2017 determined that due to the lack of sufficient material in the holotype, and that the dentaries of troodontids to not bear unique, autapomorphic features, ''Polyodontosaurus'' was a ''[nomen dubium](/source/nomen_dubium)'', and could not be considered senior synonym of ''Latenivenatrix''. Below is the phylogenetic analysis of van der Reest & Currie (2017). ''Polyodontosaurus'' has been considered a synonym of the "Two Medicine troodontid" and ''[Latenivenatrix](/source/Latenivenatrix)'' previously. {{clade| style=font-size:85%; line-height:85% |label1=[Troodontidae](/source/Troodontidae) |1={{clade |1=''[Sinovenator](/source/Sinovenator)'' |2={{clade |1=''[Anchiornis](/source/Anchiornis)'' |2={{clade |1=''[Mei](/source/Mei_long)'' |2=''[Talos](/source/Talos_sampsoni)'' |3={{clade |1=''[Byronosaurus](/source/Byronosaurus)'' |2={{clade |1=[MPC-D 100/44](/source/EK_troodontid) |2=''[Sinornithoides](/source/Sinornithoides)'' |label3='''Troodontinae''' |3={{clade |1={{clade |1=''[Urbacodon](/source/Urbacodon)'' |2=''[Gobivenator](/source/Gobivenator)'' }} |2={{clade |1={{clade |1= ''[Latenivenatrix](/source/Latenivenatrix)'' |2={{clade |1=''[Philovenator](/source/Philovenator)'' |2=''[Linhevenator](/source/Linhevenator)'' }} }} |2={{clade |1=Two medicine troodontid |2={{clade |1=''[Saurornithoides](/source/Saurornithoides)'' |2=''[Zanabazar](/source/Zanabazar_junior)'' }} }} }} }} }} }} }} }} }} }} ==Paleoecology== thumb|left|Megafaunal dinosaurs of the Dinosaur Park Formation The single specimen of ''Polyodontosaurus'' was found in the central level of the Dinosaur Park Formation, and was a member of a diverse and well-documented [fauna](/source/fauna) of prehistoric animals that included such well-known dinosaurs as the [horned](/source/ceratopsidae) ''[Centrosaurus](/source/Centrosaurus)'', ''[Styracosaurus](/source/Styracosaurus)'', and ''[Chasmosaurus](/source/Chasmosaurus)'', fellow duckbills ''[Prosaurolophus](/source/Prosaurolophus)'', ''[Gryposaurus](/source/Gryposaurus)'', ''Corythosaurus'', and ''[Parasaurolophus](/source/Parasaurolophus)'', [tyrannosaurid](/source/tyrannosaurid) ''[Gorgosaurus](/source/Gorgosaurus)'', and [armored](/source/ankylosauria) ''[Edmontonia](/source/Edmontonia)'' and ''[Euoplocephalus](/source/Euoplocephalus)''. The Dinosaur Park Formation is interpreted as a low-relief setting of [river](/source/river)s and [floodplain](/source/floodplain)s that became more [swamp](/source/swamp)y and influenced by [marine](/source/ocean) conditions over time as the [Western Interior Seaway](/source/Western_Interior_Seaway) [transgressed](/source/transgression_(geology)) westward. The [climate](/source/climate) was warmer than present-day Alberta, without [frost](/source/frost), but with wetter and drier seasons. [Conifer](/source/Conifer)s were apparently the dominant [canopy](/source/forest_canopy) plants, with an [understory](/source/understory) of [fern](/source/fern)s, [tree fern](/source/tree_fern)s, and [angiosperm](/source/angiosperm)s. ==References== {{cite journal|last=Sternberg|first=C.M.|year=1951|title=The lizard ''Chamops'' from the Wapiti Formation of Northern Alberta: ''Polyodontosaurus grandis'' is not a lizard|journal=Annual Report of the National Museum of Canada Bulletin|volume=123|pages=256–258|url=https://books.google.com/books?id=WDUeAQAAMAAJ}} {{cite journal|last1=van der Reest|first1=A.J.|last2=Currie|first2=P.J.|year=2017|title=Troodontids (Theropoda) from the Dinosaur Park Formation, Alberta, with a description of a unique new taxon: implications for deinonychosaur diversity in North America|journal=Canadian Journal of Earth Sciences|volume=54|issue=9|pages=919–935|doi=10.1139/cjes-2017-0031|bibcode=2017CaJES..54..919V|hdl=1807/78296|hdl-access=free}} {{cite journal|last=Russell|first=D.A.|year=1969|title=A new specimen of Stenonychosaurus from the Oldman Formation (Cretaceous) of Alberta|journal=Canadian Journal of Earth Sciences|volume=6|issue=4|pages=595–612|doi=10.1139/e69-059|bibcode=1969CaJES...6..595R}} {{cite book|last1=Weishampel|first1=D.B.|last2=Barrett|first2=P.M.|last3=Coria|first3=R.A.|last4=Le Loeuff|first4=J.|last5=Xu|first5=X.|last6=Zhao|first6=X.|last7=Sahni|first7=A.|last8=Gomani|first8=E.M.P.|last9=Noto|first9=C.R.|year=2004|chapter=Dinosaur Distribution|title=The Dinosauria (Second ed.)|url=https://archive.org/details/dinosauriandedit00weis|url-access=limited|publisher=University of California Press|pages=[https://archive.org/details/dinosauriandedit00weis/page/n535 517]–606|isbn=978-0-520-24209-8|editor-last=Weishampel|editor-first=D.B.|editor2-last=Dodson|editor2-first=P.|editor3-last=Osmólska|editor3-first=H.}} {{cite book|last=Eberth|first=D.A.|year=2005|chapter=The geology|editor-last=Currie|editor-first=P.J.|editor2-last=Koppelhus|editor2-first=E.B.|title=Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed|publisher=Indiana University Press|pages=[https://archive.org/details/dinosaurprovinci0000unse/page/54 54–82]|isbn=978-0-253-34595-0|chapter-url=https://archive.org/details/dinosaurprovinci0000unse/page/54}} {{cite book|last1=Braman|first1=D.R.|last2=Koppelhus|first2=E.B.|chapter=Campanian palynomorphs|editor-last=Currie|editor-first=P.J.|editor2-last=Koppelhus|editor2-first=E.B.|title=Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed|publisher=Indiana University Press|pages=[https://archive.org/details/dinosaurprovinci0000unse/page/54 54–82]|isbn=978-0-253-34595-0|year=2005|chapter-url=https://archive.org/details/dinosaurprovinci0000unse/page/54}} {{Troodontidae}} {{Taxonbar|from=Q48834266}} Category:Troodontidae Category:Dinosaur genera Category:Campanian dinosaurs Category:Dinosaur Park Formation Category:Taxa named by Charles W. Gilmore Category:Fossil taxa described in 1932 Category:Dinosaurs of Canada --- Adapted from the Wikipedia article [Polyodontosaurus](https://en.wikipedia.org/wiki/Polyodontosaurus) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Polyodontosaurus?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.