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Science 11 February 2005:
Vol. 307. no. 5711, pp. 910 - 914
DOI: 10.1126/science.1105717
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Reports

Independent Origins of Middle Ear Bones in Monotremes and Therians

Thomas H. Rich,1,2* James A. Hopson,3 Anne M. Musser,4 Timothy F. Flannery,5 Patricia Vickers-Rich2

A dentary of the oldest known monotreme, the Early Cretaceous Teinolophos trusleri, has an internal mandibular trough, which in outgroups to mammals houses accessory jaw bones, and probable contact facets for angular, coronoid, and splenial bones. Certain of these accessory bones were detached from the mandible to become middle ear bones in mammals. Evidence that the angular (homologous with the mammalian ectotympanic) and the articular and prearticular (homologous with the mammalian malleus) bones retained attachment to the lower jaw in a basal monotreme indicates that the definitive mammalian middle ear evolved independently in living monotremes and therians (marsupials and placentals).

1 Museum Victoria, Post Office Box 666E, Melbourne, Victoria 3001, Australia.
2 School of Geosciences, Post Office Box 28E, Monash University, Victoria 3800, Australia.
3 Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA.
4 Australian Museum, 6 College Street, Sydney, New South Wales 2010, Australia.
5 South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia.

* To whom correspondence should be addressed. E-mail: trich{at}museum.vic.gov.au

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
The oldest platypus and its bearing on divergence timing of the platypus and echidna clades.
T. Rowe, T. H. Rich, P. Vickers-Rich, M. Springer, and M. O. Woodburne (2008)
PNAS 105, 1238-1242
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Historical contingency and the purported uniqueness of evolutionary innovations.
G. J. Vermeij (2006)
PNAS 103, 1804-1809
   Abstract »    Full Text »    PDF »
Comment on "Independent Origins of Middle Ear Bones in Monotremes and Therians" (I).
G. S. Bever, T. Rowe, E. G. Ekdale, T. E. Macrini, M. W. Colbert, and A. M. Balanoff (2005)
Science 309, 1492a
   Full Text »    PDF »
Comment on "Independent Origins of Middle Ear Bones in Monotremes and Therians" (II).
G. W. Rougier, A. M. Forasiepi, and A. G. Martinelli (2005)
Science 309, 1492b
   Full Text »    PDF »
Response to Comments on "Independent Origins of Middle Ear Bones in Monotremes and Therians".
T. H. Rich, J. A. Hopson, A. M. Musser, T. F. Flannery, and P. Vickers-Rich (2005)
Science 309, 1492c
   Full Text »    PDF »


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