| 词条 | Diarthrognathus |
| 释义 |
| fossil_range = {{fossilrange|201|189}} Lower Jurassic | genus = Diarthrognathus | parent_authority = Crompton, 1958[1] | species = broomi | authority = Crompton, 1958 }}Diarthrognathus ("Two joint jaw") is an extinct genus of synapsids, known from fossil evidence found in South Africa[2] and first described in 1958 by A.W. Crompton.[3] The creature lived during the Late Triassic to Early Jurassic periods, about 200 million years ago.[4][3] It was carnivorous and small, slightly smaller than Thrinaxodon, which was under {{convert|50|cm|in}} long.[4]Diarthrognathus possesses a jaw structure that is similar to both mammals and more basal synapsids. Its primitive jaw joint is located between the quadrate and articular bones, and its derived, mammalian jaw joint is located between the squamosal and dentary bones.[5] The articular and quadrate bones evolved to become two of the middle-ear bones in mammals.[6] The transition exemplified by Diarthrognathus suggests that natural selection favored animals with a more powerful bite.[7] At one time, Diarthrognathus was thought to be synonymous with Pachygenelus. However, in 1980, newly discovered fossils revealed sufficient differences to warrant separate genera.[8] The double jaw joint of Diarthrognathus neatly bridges early synapsids and mammals, and thus rebuts a claim by creationists, such as Duane Gish, who thought such a transition was impossible.[9][10] This "twin-jointed jaw" can also be seen in other late cynodonts, as well as in early mammaliforms.[11] References1. ^Diarthrognathus - Paleobiology Database {{Cynodontia|P.}}{{Taxonbar|from=Q3765186}}2. ^Diarthrognathus - Encyclopædia Britannica. 3. ^1 Rieppel, Olivier. [https://books.google.com/books?id=TJCysp-6cZ0C&pg=PA190 Evolutionary Theory and the Creation Controversy], p. 190 (Springer, 2010). 4. ^Crompton, A.W. "Masticatory Function in Non-Mammalian Cynodonts and Early Mammals" in [https://books.google.com/books?id=mWLDdT8y7yAC&pg=PA64 Functional Morphology in Vertebrate Paleontology], p. 64 (J. Thomason, ed., Cambridge University Press 1997). 5. ^Prothero, Donald. [https://books.google.com/books?id=QeKWpRX77JgC&pg=PA278 Evolution: What the Fossils Say and Why It Matters], p. 278 (Columbia University Press, 2013). 6. ^1 [https://books.google.com/books?id=kFd-1DApcRYC&pg=PA183 The Mesozoic Era: Age of Dinosaurs], p. 183 (Britannica Educational Publishing, Rosen Publishing Group, 2010). 7. ^"[https://books.google.com/books?id=5z8Q-en4x6YC&pg=PA146 How Animals Got Their Bite]", New Scientist, p. 146 (July 18, 1963). 8. ^Martinelli, Agustín and Bonaparte, José."[https://www.researchgate.net/publication/233755277_A_new_tritheledontid_(Therapsida_Eucynodontia)_from_the_Late_Triassic_of_Rio_Grande_do_Sul_(Brazil)_and_its_phylogenetic_relationships_among_carnivorous_non-mammalian_eucynodonts/file/32bfe5123bb4c62117.pdf A new tritheledontid (Therapsida, Eucynodontia) from the Late Triassic of Rio Grande do Sul (Brazil) and its phylogenetic relationships among carnivorous non-mammalian eucynodonts]", Ameghiniana, Vol. 42, p. 191 (2005). 9. ^Debenedictis, Albert. [https://books.google.com/books?id=cAVEPQgIbOMC&pg=PA182 Evolution Or Creation?: A Comparison of the Arguments], p. 182 (Xlibris Corporation 2011).{{Self-published inline|certain=yes|date=January 2018}} 10. ^Kitcher, Philip. [https://books.google.com/books?id=uBu0pWK4rzIC&pg=PA111 Abusing Science: The Case Against Creationism], p. 111 (MIT Press 1982). 11. ^Colbert, Edward and Morales, Michael. Evolution of the Vertebrates: A History of the Backboned Animals Through Time, p. 228 (Wiley-Liss, 4th edition, 199) {{ISBN|0-471-85074-8}} 2 : Probainognathian genera|Jurassic synapsids of Africa |
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