Hypsilophodont
2684958
221358471
2008-06-24T04:44:39Z
Firsfron
158443
rem broken DOI
{{Taxobox
| name = Hypsilophodonts
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Reptile|Sauropsida]]
| superordo = [[Dinosaur]]ia
| ordo = [[Ornithischia]]
| subordo = [[Cerapoda]]
| infraordo = [[Ornithopoda]]
| familia = '''Hypsilophodontidae'''
| familia_authority = Dollo, 1882
| subdivision_ranks = [[Genus|Genera]]
| subdivision =
See text.
}}
'''Hypsilophodonts''' (named after the ''[[Hypsilophus]]'' [[genus]] of [[iguana]] [[lizard]], literally meaning "high-crested [[tooth]]") were small [[ornithopod]] [[dinosaur]]s, regarded as fast, [[herbivorous]] [[biped]]s on the order of 1-2 [[metre|meters]] long (3.3-6.6 [[foot (unit of length)|feet]]). They are known from [[Asia]], [[Australia]], [[Europe]], [[North America]], and [[South America]], from [[rock formation|rocks]] of [[Middle Jurassic]] to [[late Cretaceous]] age. The group traditionally has included almost all bipedal [[ornithischia|bird-hipped dinosaurs]] other than [[iguanodont]]s, and some early [[cladistics|phylogenetic analyses]] analyses found it to be a natural group,<ref name=SN90>{{cite book |last=Sues |first=Hans-Dieter |coauthors=and Norman, David B. |editor= Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.)|title=The Dinosauria |edition=1st |year=1990 |publisher=University of California Press |location=Berkeley |isbn=0-520-06727-4 |pages=498-509 |chapter=Hypsilophodontidae, ''Tenontosaurus'', Dryosauridae}}</ref><ref name=WH92>{{cite journal |last=Weishampel |first=David B. |authorlink=David B. Weishampel |coauthors=and Heinrich, Ronald E. |year=1992 |title=Systematics of Hypsilophodontidae and Basal Iguanodontia (Dinosauria: Ornithopoda) |journal=Historical Biology |volume=6 |pages=159–184 |url=http://www.tandf.co.uk/journals/pdf/ghbi_06_01_01.pdf |accessdate=2007-03-10 }}</ref> but recent studies have found that the group is mostly [[paraphyletic]] and the taxa within represent a series leading up to [[Iguanodontia]].<ref name=RS98>{{cite journal |last=Scheetz |first=Rodney D. |year=1998 |title=Phylogeny of basal ornithopod dinosaurs and the dissolution of the Hypsilophodontidae |journal=Journal of Vertebrate Paleontology |volume=18 |issue=3, Suppl. |pages=p. 75A }}</ref><ref name=WMJ98>{{cite journal |last=Winkler |first=Dale A. |coauthors=Murry, Phillip A.; and Jacobs, Louis L. |year=1998 |title=The new ornithopod dinosaur from Proctor Lake, Texas, and the deconstruction of the family Hypsilophodontidae |journal=Journal of Vertebrate Paleontology |volume=18 |issue=3, Suppl. |pages=p. 87A }}</ref><ref name=PB02>{{cite book |last=Buchholz |first=Peter W. |title=The Mesozoic in Wyoming, Tate 2002 |year=2002 |publisher=The Geological Museum, Casper College |location=Casper, Wyoming |pages=18-34 |chapter=Phylogeny and biogeography of basal Ornithischia}}</ref><ref name=WJCN03>{{cite journal |last=Weishampel |first= David B. |authorlink=David B. Weishampel |coauthors=Jianu, Coralia-Maria; Csiki, Z.; and Norman, David B. |year=2003 |title=Osteology and phylogeny of ''Zalmoxes'' (n.g.), an unusual euornithopod dinosaur from the latest Cretaceous of Romania |journal=Journal of Systematic Palaeontology |volume=1 |issue=2 |pages=1–56 |doi=10.1017/S1477201903001032 }}</ref><ref name=NSWC04>{{cite book |last=Norman |first=David B. |authorlink=David B. Norman |coauthors=Sues, Hans-Dieter; Witmer, Larry M.; and Coria, Rodolfo A. |editor=Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.)|title=The Dinosauria |edition=2nd |year= 2004|publisher=University of California Press |location=Berkeley |isbn=0-520-24209-2 |pages=393-412 |chapter=Basal Ornithopoda}}</ref><ref name=VMK07>{{cite journal |last=Varricchio |first=David J. |coauthors=Martin, Anthony J.; and Katsura, Yoshihiro |year=2007 |title=First trace and body fossil evidence of a burrowing, denning dinosaur |journal=Proceedings of the Royal Society B: Biological Sciences |volume=274 |pages=1361–1368 |doi=10.1098/rspb.2006.0443 |url=http://journals.royalsociety.org/content/uj1k12wh01587821/fulltext.pdf |accessdate=2007-03-22 }}</ref> Some of these studies have moved some traditional hypsilophodonts out of the Ornithopoda.<ref name=Butleretal07>{{cite journal |last=Butler |first=Richard J. |coauthors=Smith, Roger M.H.; and Norman, David B. |title=A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia |journal=Proceedings of the Royal Society B: Biological Sciences |year=2007 |doi= 10.1098/rspb.2007.0367 |volume=274 |pages=2041}}</ref><ref name=BUN08>{{cite journal |last=Butler |first=Richard J. |coauthors=Upchurch, Paul; and [[David B. Norman|Norman, David B.]] |title=The phylogeny of the ornithischian dinosaurs|journal=Journal of Systematic Palaeontology |volume=6 |issue=1 |year=2008 |pages=1–40 |doi=10.1017/S1477201907002271}}</ref> Thus, the only certain member at this time is ''[[Hypsilophodon]]''. This area of the dinosaur family tree is complicated by a lack of research.
==Relationships==
The following [[cladistics|cladogram]] of hypsilophodont relationships supports the [[paraphyly|paraphyletic]] hypotheses; the "natural Hypsilophodontidae" hypothesis has been falling out of favor since the mid-late 1990s.
{{clade| style=font-size:100%;line-height:80%
|label1=[[Ornithopod|Euornithopoda]]
|1={{clade
|1=''[[Orodromeus]]''
|2=''[[Othnielosaurus]]''
|label3=<font color="white">unnamed</font>
|3={{clade
|label1=<font color="white">unnamed</font>
|1={{clade
|1=''[[Gasparinisaura]]''
|2=''[[Hypsilophodon]]''
|3=''[[Zephyrosaurus]]''
}}
|label2=<font color="white">unnamed</font>
|2={{clade
|label1=<font color="white">unnamed</font>
|1={{clade
|1=?''[[Bugenasaura]]''
|2=''[[Parksosaurus]]''
|3=''[[Thescelosaurus]]''
}}
|2=[[Iguanodont]]ia
}}
}}
}}
}}
This cladogram is based on Norman ''et al.'' (2004),<ref name=NSWC04/> the most recent review, with the results of the very similar cladogram from Weishampel ''et al.'' (2003)<ref name=WJCN03>{{cite journal |last=Weishampel |first= David B. |authorlink=David B. Weishampel |coauthors=Jianu, Coralia-Maria; Csiki, Z.; and Norman, David B. |year=2003 |title=Osteology and phylogeny of ''Zalmoxes'' (n.g.), an unusual euornithopod dinosaur from the latest Cretaceous of Romania |journal=Journal of Systematic Palaeontology |volume=1 |issue=2 |pages=1–56 |doi=10.1017/S1477201903001032 }}</ref> used to clarify the position of Iguanodontia, which was left out of Norman ''et al.'' Thescelosaurinae is currently used informally.
The following genera were regarded as valid, but weren't classified:<ref name=NSWC04/>
*''[[Atlascopcosaurus]]''
*''[[Drinker]]''
*"[[Gongbusaurus]]" ''wucaiwanensis'' (= "[[Eugongbusaurus]]")
*''[[Fulgurotherium]]''
*''[[Leaellynasaura]]''
*''[[Notohypsilophodon]]''
*''[[Qantassaurus]]''
*''[[Yandusaurus]]''
*"Proctor Lake hypsilophodont"
Several other genera belong here somewhere, but are very poorly known or outright dubious:<ref name=NSWC04/>
*''[[Laosaurus]]''
*''[[Nanosaurus]]''
*''[[Othnielia]]'' (without [[Othnielosaurus|"Laosaurus" ''consors'']])
*''[[Phyllodon]]''
===Alternate versions and new data===
Several recent studies on the base of Ornithischia, such as Butler (2005),<ref name=RJB05>{{cite journal |last=Butler |first=Richard J. |year=2005 |title=The "fabrosaurid" ornithischian dinosaurs of the Upper Elliot Formation (Lower Jurassic) of South Africa and Lesotho |journal=Zoological Journal of the Linnean Society |volume=145 |issue=2 |pages=175–218 |doi=10.1111/j.1096-3642.2005.00182.x }}</ref> Barrett ''et al.'' (2005),<ref name=BBK05>{{cite journal |last=Barrett |first=Paul M. |coauthors=Butler, Richard J.; and Knoll, Fabian |year=2005 |title=Small-bodied ornithischian dinosaurs from the Middle Jurassic of Sichuan, China |journal=Journal of Vertebrate Paleontology |volume=25 |issue=4 |pages=823–834 |doi=10.1671/0272-4634(2005)025[0823:SODFTM]2.0.CO;2 }}</ref> Xu ''et al.'' (2006),<ref name=XFCM06>{{cite journal |last=Xu X. |coauthors=Forster, C.A.; Clark, J.M.; and Mo J. |year=2006 |title=A basal ceratopsian with transitional features from the Late Jurassic of northwestern China |journal=Proceedings of the Royal Society B: Biological Sciences |volume=273 |pages=2135–2140 |doi= }}</ref> and Butler ''et al.'' (2007)<ref name=Butleretal07/> have found different arrangements of basal Ornithischia and basal ornithopods that have some bearing on the tree, but each has found different relationships. Given the lack of work on this area since the 1980s, this is not unexpected. One aspect is the reclassification of several genera outside of Ornithopoda, such as ''[[Agilisaurus]]'' and ''[[Othnielosaurus]]'' (=''[[Othnielia]]'').<ref name=VMK07>{{cite journal |last=Varricchio |first=David J. |coauthors=Martin, Anthony J.; and Katsura, Yoshihiro |year=2007 |title=First trace and body fossil evidence of a burrowing, denning dinosaur |journal=Proceedings of the Royal Society B: Biological Sciences |volume=online preprint |doi=10.1098/rspb.2006.0443 |pages=1361}}</ref><ref name=BUN08/>
Varricchio ''et al.'' (2007) found that their new genus, ''[[Oryctodromeus]]'', forms a [[clade]] with two other genera from Montana, ''Orodromeus'' and ''Zephyrosaurus''.<ref name=VMK07/>
==Paleobiology==
Hypsilophodonts were small (often 1-2 m [3.28 to 6.56 ft] long), [[biped]]al, [[cursorial]] [[herbivores]].<ref name=NSWC04/> The typical informal comparison has been to [[gazelle]]s. However, there is evidence that at least some of them made [[burrow]]s as places to rear their young.<ref name=VMK07/>
==References==
{{reflist}}
{{portalpar|Dinosaurs}}
[[Category:Ornithopods| ]]
[[de:Hypsilophodontidae]]
[[eo:Hipsilofodontedoj]]
[[fr:Hypsilophodontidae]]
[[it:Hypsilophodontidae]]
[[hu:Hypsilophodontidae]]
[[pl:Hipsylofodony]]
[[zh:棱齒龍科]]