Records of the Western Australian Museum 17: 287-308 (1995). 
Sharks from the Middle-Late Devonian Aztec Siltstone, 
southern Victoria Land, Antarctica 
John A. Long 1 and Gavin C. Young 2 
1 Western Australian Museum, Francis Street, Perth, Western Australia 6000 
2 Australian Geological Survey Organisation, P.O. Box 378, Canberra, A.C.T. 2601 
Abstract - Shark teeth representing three new taxa are described from the 
Middle-Late Devonian Aztec Siltstone of southern Victoria Land, Antarctica. 
Portalodus bradshawae gen. et sp. nov. is represented by large diplodont teeth 
which have a base with a well-produced labial platform. It occurs in the 
middle to upper sections of the Aztec Siltstone. Aztecodus harmsenae gen. et 
sp. nov. is represented by broad bicuspid teeth, wider than high, with 
numerous medial crenulations and twin nutritive foramina penetrating the 
rectangular base. It occurs in the middle sections of the Aztec Siltstone. The 
teeth of Anareodus statei gen. et sp. nov. are characterised by having a main 
cusp which is more than twice as high as the second cusp, a small cusplet 
developed on the outer cutting edge of the main cusp, sometimes with few 
crenulations developed in the middle of the two cusps, and the base is 
strongly concave. Antarctilamna cf. prisca Young, 1982 is also recorded from 
the middle and upper sections of the Aztec Siltstone above the thelodont 
horizons and occurring with phyllolepids and Pambulaspis in the Cook 
Mountains section south of Mt Hughes. The chondrichthyan fauna from the 
Aztec Siltstone now contains at least 5 species, being the most diverse 
assemblage of Middle Devonian chondrichthyans (based on teeth) from one 
stratigraphic unit. 
INTRODUCTION 
Fossil shark remains were first identified in the 
Devonian Aztec fish fauna of southern Victoria 
Land in the material collected from moraine at 
Granite Harbour, near the coast of McMurdo 
Sound, during the British Antarctic Terra Nova' 
Expedition of 1910-13. Among the fish scales 
observed in thin section were some which 
Woodward (1921: 57) described as 'typically 
Elasmobranch, each large cusp showing a trace of 
an original pulp cavity'. Many of these scales 
subsequently turned out to be thelodont scales, 
whose existence in a fish fauna of Late Devonian 
aspect was completely unsuspected by Woodward 
and other early workers. These were recently 
described as a new species of Turitiia by Turner 
and Young (1992). White (1968), who studied the 
first in situ material, collected by B.M. Gunn and 
G. Warren during the Trans-Antarctic Expedition 
of 1958 (Gunn and Warren 1962), then found one 
definitive shark specimen, a single tooth which he 
described as a new form, Mcmurdodus featherensis, 
placed in a new family Mcmurdodontidae. This 
specimen came from Mt Feather, 18 km due east of 
the Lashly Range (Figure 1). Young (1982) 
described a second shark, Antarctilamna prisca, 
based on partially articulated remains which 
included teeth, scales and fin-spines also provided 
the first illustrations of the large diplodont teeth 
from Portal Mountain recorded by Ritchie (1971) 
as resembling those of Xenacanthus sp. These shark 
remains form part of a diverse fish fauna from the 
Aztec Siltstone, including arthrodires (Ritchie 1975; 
Long in press), antiarchs (Young 1988), 
acanthodians (Young 1989b), rhipidistians (Young 
et al. 1992), lungfish (Woolfe et al. 1990, Young 
1991), and an undescribed actinopterygian (Young 
1991). The faunal list now stands at 22 named 
genera and 31 species, including the new forms 
described here, of which all species and 18 genera 
are endemic to the region of East Gondwana (Table 
1 ). 
The material described herein comes mainly 
from a new collection of Aztec Siltstone fossils 
made by J. Long on the joint 1991/92 New Zealand 
Antarctic Research Program-Australian National 
Antarctic Research Expedition trip to the Cook 
Mountains and Skelton N6vd regions, but also 
includes shark material previously collected by A. 
Ritchie and G.C. Young during the Victoria 
University of Wellington Antarctic Expedition 
VUWAE 15 (1970/71 season). The new material is 
sufficient to describe three new genera of Devonian 
sharks, based on teeth. In addition, information 
from the new localities in the Cook Mountains 
extends the known stratigraphic range of 
