Bull. not. Hist. Mus. Land. (Geol.) 54(2): 147-154 



Issued 26 November 1998 



The first Palaeozoic rhytidosteid: 

 Trucheosaurus major (Woodward, 1909) from 

 the Late Permian of Australia, and a 

 reassessment of the Rhytidosteidae (Amphibia, 

 Temnospondyli) 



CLAUDIA A. MARSICANO 



Departamento de Cierrcias ueologicas, Universidad de Buenos Aires, Ciudad Universitaria Pab. II, 1428 

 Buenos Aires, Argentina 



ANNE WARREN 



School of Zoology, La Trobe University, Bundoora, Victoria 3083, Australia 



SYNOPSIS. A restudy of Bothriceps major, a temnospondyl from the Late Permian of Australia, has resulted in a new taxonomic 

 assignment of the specimen. The species is returned to Trucheosaurus and the specimen is recognized as a rhytidosteid, rather than 

 a brachyopid. Thus, it constitutes the first Palaeozoic record of the Rhytidosteidae, which has long been considered to be restricted 

 to the Early Triassic. A phylogenetic analysis of all taxa previously included in the superfamily Rhytidosteoidea was performed. 

 One monophyletic group, the family Rhytidosteidae, is recognized, but the relationships of most taxa within that clade remain 

 unresolved. 



INTRODUCTION 



In 1909, Woodward described a new Australian brachyopid taxon, 

 Bothriceps major, based on a specimen collected in Late Permian 

 deposits from the Sydney Basin (New South Wales). The genus was 

 previously erected by Huxley ( 1859) for an Australian brachyopid, 

 B. australis, represented by a single skull of unknown provenance 

 (Watson 1919, 1956; Welles & Estes 1969; Warren 1997). Subse- 

 quently, Watson ( 1956) restudied B. major and referred the specimen 

 to a new genus of brachyopid, Trucheosaurus, largely because 'in 

 the few structures clearly shown in the only known specimen it 

 differs from the type of the genus Bothriceps and indeed from all 

 other known genera of the family', and also because 'the specimen 

 is important as showing the occurrence of a typical brachyopid at an 

 early horizon'. Subsequently, Cosgriff (1969) presented a brief 

 redescription of T. major based on his own observation of part of the 

 type material (MMF 12697), and also discussed the age of the 

 specimen. Welles & Estes (1969) argued that the new genus, 

 Trucheosaurus, could not be justified, so they returned the species to 

 Bothriceps. 



The holotype material of B. major consists of a poorly preserved 

 specimen which includes the skull and a partial articulated postcranial 

 skeleton. At present, the specimen comprises four pieces distributed 

 in three different repositories: the skull (MMF 12697a) is in the 

 Geological Survey of New South Wales (Sydney), the postcranial 

 skeleton (AMF 50977) in the Australian Museum (Sydney), and the 

 counterpart of both skull and postcranial skeleton (BMNH R3728) 

 in the collections of The Natural History Museum, London. 



The present paper is a redescription and a reassessment of the 

 taxonomic position of B. major based on a re-evaluation of the entire 

 holotype material. It was prompted during our joint study of the 

 material in 1995 when the Australian part of the skull was further 

 prepared, revealing an extended quadratojugal area on the left hand 

 side. The specimen then assumed a triangular shape, with the 



© The Natural History Museum. 1998 



Xx^n^dS^ 



posterior margin apparently lacking both tabular projections and 

 otic embayment, a morphology found in several members of the 

 family Rhytidosteidae. A few patches of rhytidosteid ornament were 

 also present. Bothriceps major is returned to Watson's available 

 taxon, Trucheosaurus, and included in the family Rhytidosteidae. A 

 preliminary phylogenetic analysis of the family Rhytidosteidae is 

 presented and the position of the taxon discussed in a cladistic 

 context. 



SYSTEMATIC PALAEONTOLOGY 



TEMNOSPONDYLI Zittel. 1888 



Family RHYTIDOSTEIDAE Huene, 1920 



Genus TRUCHEOSAURUS Watson. 1956 



TYPE SPECIES. Bothriceps major Woodward 1909; Late Permian 

 (Dzhulfian). Sydney Basin, New South Wales, Australia. 



Diagnosis. As for the type and only species. 



Trucheosaurus major (Woodward 1909) 



Figs 1-6 



1909 Bothriceps major Woodward: 319, pi. LI. 



1956 Trucheosaurus major ('Woodward) .Watson: 327-330,fig. 3. 



1969 Bothriceps major Woodward; Welles & Estes: 22. 



1969 Trucheosaurus major (Woodward); Cosgriff: 80. 



1972 Trucheosaurus major (Woodward); Howie: 269. 



1973 Trucheosaurus major (Woodward); Cosgriff: 1095-1 100. 



1974 Trucheosaurus major (Woodward); Cosgriff: 94. 

 1977 Bothriceps major Woodward; Chernin: 88. 

 1981 Bothriceps major Woodward; Warren: 273. 

 1997 Bothriceps major Woodward; Warren: 27, fig. 3. 



