Sinoconodon

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Extinct genus of mammaliamorphs

title: "Sinoconodon" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["mammaliamorpha", "transitional-fossils", "early-jurassic-synapsids-of-asia", "sinemurian-life", "fossils-of-china", "fossil-taxa-described-in-1961", "taxa-named-by-bryan-patterson", "taxa-named-by-everett-c.-olson"] description: "Extinct genus of mammaliamorphs" topic_path: "geography/china" source: "https://en.wikipedia.org/wiki/Sinoconodon" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct genus of mammaliamorphs ::

| fossil_range = Sinemurian ~ | image = Sinoconodon rigneyi.svg | image_caption = Life restoration of Sinoconodon rigneyi | display_parents = 4 | greatgrandparent_authority = Kinman, 1994 | grandparent_authority = Mills, 1971 | genus = Sinoconodon | parent_authority = Patterson & Olson, 1961 | species = rigneyi | authority = Patterson & Olson, 1961 | synonyms = {{collapsible list | Genera

  • Lufengoconodon Young 1982a | Species
  • Lufengoconodon changchiawaensis Young 1982a
  • Sinoconodon changchiawaensis (Young 1982) sensu Crompton & Sun 1985
  • Sinoconodon parringtoni Young 1982
  • Sinoconodon youngi Zhang 1983

Sinoconodon is an extinct genus of mammaliamorphs that appears in the fossil record of the Lufeng Formation of China in the Sinemurian stage of the Early Jurassic period, about 193 million years ago. While sharing many plesiomorphic traits with other non-mammaliaform cynodonts, it possessed a special, secondarily evolved jaw joint between the dentary and the squamosal bones, which in more derived taxa would replace the primitive tetrapod one between the articular and quadrate bones. The presence of a dentary-squamosal joint is a trait historically used to define mammals.{{cite book | last1 = Kielan-Jaworowska | first1 = Z | author-link = Zofia Kielan-Jaworowska | last2 = Luo | first2 = ZX | last3 = Cifelli | first3 = RL | title = Mammals from the Age of Dinosaurs | at= Chapter 4 | publisher = Columbia University Press | year= 2004 | isbn = 9780231119184}}

Description

::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/b2/Sinoconodon_skull.jpg" caption="Fossil skull, [[Baoding Natural History Museum"] ::

This animal had a skull of 6 cm, which suggests a presacral body length of 25 cm and a weight of about 800 g due to the similar parameters to the European hedgehog.{{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 | last1 = Luo | first1 = ZX | last2 = Kielan-Jaworowska | first2 = Z | author2-link = Zofia Kielan-Jaworowska | last3 = Cifelli | first3 = RL | title = In quest for a phylogeny of Mesozoic mammals | journal = Acta Palaeontologica Polonica | year = 2002 | volume = 47 | issue = 1 | pages = 1–78}} differing substantially from Morganucodon in its dentition and growth habits. Like most other non-mammalian tetrapods, such as reptiles and amphibians, it was polyphyodont, replacing many of its teeth throughout its lifetime, and it seems to have grown slowly but continuously until its death. It was thus somewhat less mammal-like than mammaliaforms such as morganucodonts and docodonts. The combination of basal tetrapod and mammalian features makes it a unique transitional fossil.

Taxonomy

Sinoconodon was named by Patterson and Olson in 1961. Its type is Sinoconodon rigneyi. It was assigned to Triconodontidae by Patterson and Olson in 1961; to Triconodonta by Jenkins and Crompton in 1979; to Sinoconodontidae by Carroll in 1988; to Mammaliamorpha by Wible in 1991; to Mammalia by Luo and Wu in 1994; to Mammalia by Kielan-Jaworowska et al. in 2004; and to Mammaliaformes by Luo et al. in 2001 and Bi et al. in 2014.

Phylogeny

|label1=Mammaliaformes |1={{clade |1=Adelobasileus |2={{clade |1=Sinoconodon |2={{clade |1={{clade |1=Morganucodon |2=Megazostrodon |2={{clade |1=Haramiyida |2={{clade |1={{clade |1=Haldanodon |2=Castorocauda |2={{clade |1=Hadrocodium |2=Mammalia

References

References

  1. Lucas, Spencer. (2001). "Chinese Fossil Vertebrates". Columbia University Press.
  2. Luo, Z.-X.. (2005). "Encyclopedia of Geology". Elsevier.
  3. (August 2015). "Evidence for a Mid-Jurassic Adaptive Radiation in Mammals". Current Biology.
  4. [https://web.archive.org/web/20040925071034/http://www.geocities.com/trevor_dykes/mammalsbasal.htm Mammals of the Mesozoic: The least mammal-like mammals]
  5. "PBDB".

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mammaliamorphatransitional-fossilsearly-jurassic-synapsids-of-asiasinemurian-lifefossils-of-chinafossil-taxa-described-in-1961taxa-named-by-bryan-pattersontaxa-named-by-everett-c.-olson