Abstract

A skull of the basal trematosauroid temnospondyl Thoosuchus yakovlevi from the Early Triassic of Russia is described. Characters showing phylogenetic affinities with the Trematosauroidea include the presence of a postorbital-prepineal growth zone, the well-developed sensory sulci, the ventrally knife-edged cultriform process of the parasphenoid, and the posteriorly expanded parasphenoid body. A preliminary phylogenetic analysis of trematosauroid relationships confirms that Benthosuchus is a basal trematosaurian rather than a basal mastodonsauroid, and that Thoosuchus is the sister group to all other trematosauroids. Relationships within the Trematosauroidea are poorly established with as yet little evidence for subdivision of the group as previously proposed. In addition, the hypothesis that the Metoposauroidea is nested within the Trematosauroidea is supported. However, the Trematosauridae sensu stricto appears to be paraphyletic. The basal stereospondyl dichotomy between the Mastodonsauroidea and its relatives (the Capitosauria), and the Trematosauroidea and its relatives (the Trematosauria), is supported, and now seems well established.

 
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Bibliographic Data

Short Form
Damiani and Yates, 2003, Rec. Aust. Mus. 55(3): 331–342
Author
Ross J. Damiani; Adam M. Yates
Year
2003
Title
The Triassic amphibian Thoosuchus yakovlevi and the relationships of the Trematosauroidea (Temnospondyli: Stereospondyli)
Serial Title
Records of the Australian Museum
Volume
55
Issue
3
Start Page
331
End Page
342
DOI
10.3853/j.0067-1975.55.2003.1388
Language
English
Date Published
10 December 2003
Cover Date
10 December 2003
ISSN
0067-1975
CODEN
RAUMAJ
Publisher
The Australian Museum
Place Published
Sydney, Australia
Subjects
PALAEONTOLOGY; TRIASSIC: EARLY; FOSSIL
Digitized
10 December 2003
Available Online
10 December 2003
Reference Number
1388
EndNote
/Uploads/Journals/17964/1388.enw
Title Page
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Complete Work
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