View source for Biology:Hadrocodium

{{short description|Extinct genus of mammaliaforms}}
{{Automatic taxobox
| fossil_range = Sinemurian<br>~{{Fossil range|195}}
| image = Hadrocodium-000.jpg
| image_caption = 
| taxon = Hadrocodium
| authority = Luo, Crompton, & Sun, 2001
| subdivision_ranks = Species
| subdivision = * '''''H. wui'''''<br><small>Luo, Crompton, & Sun, 2001</small>
}}

'''''Hadrocodium wui''''' is an extinct [[Biology:Mammaliaformes|mammaliaform]] that lived during the Sinemurian stage of the Early Jurassic approximately {{Mya|195}}<ref name="Luo-etal-2001-abst">{{harvnb|Luo|Crompton|Sun|2001| loc=Abstract}}</ref> in the [[Earth:Lufeng Formation|Lufeng Formation]] in what is now the Yunnan province in south-western China<ref name="NG-2001">{{Harvnb|Parsell|2001}}</ref>
({{Coord|25.2|102.1|display=inline}}, paleocoordinates {{Coord|34.3|104.9|display=inline}}).<ref>{{Paleodb|collection|11805|Hei Koa Peng, Lufeng (CUP, IVPP) (Jurassic of China)}}. Retrieved April 2013.</ref> It is considered as the closest relative of the class Mammalia.

The fossil of this mouse-like, paper-clip sized animal was discovered in 1985 but was then interpreted as a juvenile [[Biology:Morganucodon|morganucodon]]tid.<ref name="Luo-etal-2001-ref1" /> ''Hadrocodium'' remained undescribed until 2001; since then its large brain and advanced ear structure<ref name="CNN-2011">{{Harvnb|CNN|2001}}</ref> have greatly influenced the interpretation of the earliest stages of [[Biology:Evolution of mammals|mammalian evolution]], as these mammalian characters could previously be traced only to some {{Mya|150|million years ago}}.<ref name="Carnegie-2001">{{Harvnb|CMNH|2001}}</ref> ''Hadrocodium'' is known only from a skull {{cvt|1.2|cm}} long, and its body would have measured {{cvt|3.2|cm}} long in total and weighed up to {{cvt|2|g}}, making it one of the smallest Mesozoic mammaliaforms.<ref name="Luo-etal-2001-abst" /><ref>{{cite book
| isbn = 9780198507611
| url = https://books.google.com/books?id=GswTDAAAQBAJ&dq=Gobiconodon+kg&pg=PA183
| title = The Origin and Evolution of Mammals
| publisher = Oxford University Press, USA
| date = 2005
| access-date = 22 September 2022
| page = 183
| author = T. S. Kemp
}}</ref><ref>{{cite book
| title       = The Princeton Field Guide to Prehistoric Mammals
| publisher   = Princeton University Press
| date        = November 15, 2016
| page        = 27
| author      = Donald R. Prothero
| isbn = 9780691156828
}}</ref> The specimen is thought to have been that of a mature adult.<ref name=":0">{{Cite journal |last=Luo |first=Zhexi |last2=Bhullar |first2=Bhart-Anjan |last3=Crompton |first3=Alfred |last4=Neander |first4=April |last5=Rowe |first5=Timothy |date=2022 |title=Reexamination of the Mandibular and Dental Morphology of the Early Jurassic Mammaliaform Hadrocodium wui |url=http://dx.doi.org/10.4202/app.00949.2021 |journal=Acta Palaeontologica Polonica |volume=67 |doi=10.4202/app.00949.2021 |issn=0567-7920|doi-access=free }}</ref>

The name ''Hadrocodium'' alludes to its large cranial cavity,<ref>{{cite journal |last1=Luo |first1=Z.-X. |title=A New Mammaliaform from the Early Jurassic and Evolution of Mammalian Characteristics |journal=Science |volume=292 |issue=5521 |pages=1535–40 |year=2001 |pmid=11375489 |doi=10.1126/science.1058476 |bibcode=2001Sci...292.1535L |s2cid=8738213 }}</ref> deriving from the Greek word {{transl|grc|hadrós}} ({{wikt-lang|grc|ἁδρός}} 'large, heavy, fullness')<ref name="Luo-etal-2001-ref1">{{Harvnb|Luo|Crompton|Sun|2001| loc=Note 1}}</ref> and the Latin word {{lang|la|codium}}, from Greek {{transl|grc|kṓdeia}} ({{wikt-lang|grc|κώδεια}} 'head [of a plant]').<ref>{{Harvnb|Liddell|Scott|1940}}</ref> The species name, ''wui'', is the Latinized version of discoverer Xiao-Chun Wu's name.<ref name="NG-2001"/>

While initially suggested to have possessed a fully mammalian ear akin to those of modern mammals, a 2022 restudy suggested that it actually had a primitive mandibular middle ear similar to those of other primitive mammaliaforms.<ref name=":0" />

==Phylogeny==
{{main|Biology:Evolution of mammals}}

{{clade| style=font-size:90%;line-height:100%
  |label1=Cynodontia
  |1={{clade
    |1={{clade
      |1=''[[Biology:Dvinia|Dvinia]]''
      |2=[[Biology:Procynosuchidae|Procynosuchidae]]
    }}
    |label2=[[Biology:Epicynodontia|Epicynodontia]]
    |2={{clade
      |1=''[[Biology:Thrinaxodon|Thrinaxodon]]''
      |label2=[[Biology:Eucynodontia|Eucynodontia]]
      |2={{clade
        |1={{clade
        |1=''[[Biology:Cynognathus|Cynognathus]]''
        |2={{clade
          |1=[[Biology:Tritylodontidae|Tritylodontidae]]
          |2=[[Biology:Traversodontidae|Traversodontidae]]}} }}
          |label2=[[Biology:Probainognathia|Probainognathia]]
          |2={{clade
            |1={{clade
            |1=[[Biology:Tritheledontidae|Tritheledontidae]]
            |2=[[Biology:Chiniquodontidae|Chiniquodontidae]]}}
            |2={{clade
              |1=''[[Biology:Prozostrodon|Prozostrodon]]''
              |label2=[[Biology:Mammaliaformes|Mammaliaformes]]
                |2={{clade
                  |1=[[Biology:Morganucodon|Morganucodon]]tidae
                  |2={{clade
                    |1=[[Biology:Docodonta|Docodonta]]
                    |2={{clade
                      |1='''''Hadrocodium'''''
                      |2={{clade
                        |1=[[Biology:Kuehneotheriidae|Kuehneotheriidae]]
                        |2=[[Biology:Crown group|crown group]] Mammals
                      }}
                    }}
                  }}
                }}
              }}
            }}
          }}
        }}
      }}
    }}

;Phylogeny <ref>{{cite journal|last1=Close|first1=Roger A.|last2=Friedman|first2=Matt|last3=Lloyd|first3=Graeme T.|last4=Benson|first4=Roger B.J.|year=2015|title=Evidence for a mid-Jurassic adaptive radiation in mammals.|journal=Current Biology|volume=25|issue=16|pages=2137–2142|doi=10.1016/j.cub.2015.06.047|pmid=26190074|doi-access=free}}</ref>
{{clade |style=font-size:95%;line-height:80%;
|label1=[[Biology:Mammaliaformes|Mammaliaformes]]&nbsp;
|1={{clade
|1=&nbsp;''[[Biology:Adelobasileus|Adelobasileus]]''
|2={{clade
|1=&nbsp;''[[Biology:Sinoconodon|Sinoconodon]]''
|2={{clade
|1={{clade
|1=&nbsp;''[[Biology:Morganucodon|Morganucodon]]''
|2=&nbsp;''[[Biology:Megazostrodon|Megazostrodon]]''
}}
|2={{clade
|1=&nbsp;[[Biology:Haramiyida|Haramiyida]]
|2={{clade
|1={{clade
|1=&nbsp;''[[Biology:Haldanodon|Haldanodon]]''
|2=&nbsp;''[[Biology:Castorocauda|Castorocauda]]''
}}
|2={{clade
|1=&nbsp;'''''Hadrocodium'''''
|2=&nbsp;Mammalia
}} }} }} }} }} }} }}

== See also ==
* Smallest organisms
* [[Biology:Evolution of mammalian auditory ossicles|Evolution of mammalian auditory ossicles]]

== References ==
{{Reflist|30em}}

=== Bibliography ===
{{Refbegin|30em}}
* {{Cite web
 |title       = Hadrocodium wui
 |publisher   = Carnegie Museum of Natural History
 |year        = 2001
 |url         = http://www.carnegiemnh.org/vp/hadrocodium.html
 |access-date  = 1 April 2013
 |ref         = {{Harvid|CMNH|2001}}
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20120617190702/http://www.carnegiemnh.org/vp/hadrocodium.html
 |archive-date = 2012-06-17
}}
* {{Cite web
 | title = Tiny creature may be ancestor of all mammals
 | publisher = CNN | date = May 24, 2001
 | url = http://archives.cnn.com/2001/TECH/science/05/24/tiny.ancestor/index.html | access-date = 1 April 2013
 | ref = {{Harvid|CNN|2001}}}}
* {{Cite web
 | title = A Greek–English Lexicon: κώδεια
 | year = 1940 | publisher = Perseus Digital Library
 | url = https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dkw%2Fdeia | access-date = 1 April 2013
 }}<!-- {{Harvnb|Liddell|Scott|1940}} -->
* {{Cite journal | last1 = Luo | first1 = Zhe-Xi | last2 = Crompton | first2 = Alfred W. | last3 = Sun | first3 = Ai-Lin | title = A New Mammaliaform from the Early Jurassic and Evolution of Mammalian Characteristics | year = 2001 | journal = Science | volume = 292 | issue = 5521 | pages = 1535–1540 | url = http://www.bi.ku.dk/dna/course/papers/J1.luo.pdf | doi = 10.1126/science.1058476 | pmid = 11375489 | bibcode = 2001Sci...292.1535L | s2cid = 8738213 | url-status = dead | archive-url = https://www.webcitation.org/6J0mLMZqR?url=http://www.bi.ku.dk/dna/course/papers/J1.luo.pdf | archive-date = 2013-08-20 }}<!-- {{Harvnb|Luo|Crompton|Sun|2001}} -->
* {{Cite news
 | last = Parsell | first = D.L.
 | title = Tiny Fossil From Early Jurassic Fills New Niche in Mammal Evolution
 | date = May 24, 2001 | publisher = National Geographic News
 | url = http://news.nationalgeographic.com/news/2001/05/0524_paperclipmammal.html | archive-url = https://web.archive.org/web/20010813185423/http://news.nationalgeographic.com/news/2001/05/0524_paperclipmammal.html | url-status = dead | archive-date = August 13, 2001 | access-date = 1 April 2013
 }}<!-- {{Harvnb|Parsell|2001}} -->
* {{Cite journal
 | last1 = Rowe | first1 = Timothy
 | last2 = Macrini | first2 = Thomas E
 | last3 = Luo | first3 = Zhe-Xi
 | title = Fossil Evidence on Origin of the Mammalian Brain
 |date=May 2011 | journal = Science | volume = 332 | issue = 955
 | doi = 10.1126/science.1203117 | bibcode = 2011Sci...332..955R | pmid=21596988 | pages=955–7| s2cid = 940501
 }}<!-- {{Harvnb|Rowe|Macrini|Luo|2011}} --> [https://www.science.org/doi/10.1126/science.1203117 (Supporting online material)]
{{Refend}}

==External links==
* {{Cite web
 | last1 = Rowe | first1 = Timothy
 | last2 = Macrini | first2 = Thomas E
 | last3 = Luo | first3 = Zhe-Xi
 | title = Hadrocodium wui (On-line)
 | publisher = Digital Morphology at the University of Texas | year = 2006
 | url = http://www.digimorph.org/specimens/Hadrocodium_wui/
 | access-date = 1 April 2013
}}&nbsp;— 3D models from CT scans of the original fossil
* [http://www.palaeocritti.com/by-group/mammaliaformes/hadrocodium Palaeocritti - a guide to prehistoric animals]

{{Taxonbar|from=Q133941}}

[[Category:Sinemurian life]]



{{Sourceattribution|Hadrocodium}}