Mandible and dentition ofAsfaltomylos patagonicus(Australosphenida, Mammalia) and the evolution of tribosphenic teeth
| Autor: | Thomas Martin, Oliver W. M. Rauhut |
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| Rok vydání: | 2005 |
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| Zdroj: | Journal of Vertebrate Paleontology. 25:414-425 |
| ISSN: | 1937-2809 0272-4634 |
| DOI: | 10.1671/0272-4634(2005)025[0414:madoap]2.0.co;2 |
| Popis: | The mandible of Asfaltomylos patagonicus from the late Middle Jurassic (Callovian) of Cerro Condor (Chubut, Argentina) combines a derived dentition (?i, ?c, ?5p, 3m) with tribosphenic molars together with plesiomorphic mandibular characters such as the presence of a postdentary trough and a mandibular foramen in a very anterior position. Talonids on m2 and m3 are wider than long which represents an important synapomorphy with Gondwanan australosphenidans. Talonids have an inflated hypoconid and bulging hypoconulid. As in other australosphenidans and toothed monotremes, talonid wear in Asfaltomylos is apical and no wear facets occur within the talonid basin. On m3, a common wear facet covers the apices of hypoconid and hypconulid, and the hypocristid. Crompton's (1971) standard wear facets 5 and 6 of tribosphenic boreosphenidans are not developed; therefore, it is uncertain whether a functional protocone, with its facets 5 and 6, would be present in the upper molars. The highly specialized apical ... |
| Databáze: | OpenAIRE |
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