New data on the structure of the Early Devonian lungfish,Dipnorhynchus
作者:
K.S.W. Campbell,
R.E. Barwick,
I.D. Lindley,
期刊:
Alcheringa: An Australasian Journal of Palaeontology
(Taylor Available online 2000)
卷期:
Volume 24,
issue 4
页码: 277-298
ISSN:0311-5518
年代: 2000
DOI:10.1080/03115510008619532
出版商: Taylor & Francis Group
关键词: Dipnoans;Dipnorhynchus;skull;parasphenoid;braincase;palatoquadrate;Early Devonian;Australia
数据来源: Taylor
摘要:
A skull of a young specimen ofDipnorhynchus sussmilchi(Etheridge Jr), from the base of the Bloomfield Limestone Member (mid-Emsian, probablyperbonusZone) at Taemas, has both sides of the skull roof preserved, but the cheeks are missing. The posterior end of the endocranium, up to its dorsal extremity, provides new data on the endolymphatic sacs, and the attachment of the epaxial muscles. The endolymphatic region is compared with that ofChirodipterus australis. The palate is not fully formed and the marginal ridges are not fully developed. The fine structures around the dermopalatines and the pterygoids are preserved, indicating the manner in which the plates grew. The position of the parasphenoid is clearly outlined against the pterygoids, and confirms the view that this primitive genus of dipnoans did not have the pterygoids divided by the parasphenoid. All these features provide new information and comparison withDipterus valenciennesi, the next oldest genus on which the same regions are preserved. In addition, a new mandible from a horizon low in the Cavan Bluff Formation is well preserved and provides information on the external bones ofDipnorhynchus.
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