Devonian sharks from Antarctica 
295 
Figure 6 Portalodus bradshauwe gen. et sp. nov. A, Holotype WAM 92.3.60, labial view. B, WAM 92.3.63, labial view. 
C, WAM 94.2.10 showing basal view; D,WAM 94.2.8, labial view. E, CPC 21224 (from Young, 1982 text-fig. 
3F). Bar scales are all 1 mm. 
from locality 11 of Young (1988), section 10 of 
Barrett and Webb (1973), all from unit 17 except 
CPC21214, 215 (from unit 26); WAM 92.3.60, 
92.3.63, 94.2.1, 94.2.8,, section about 200 m west of 
locality 12 of Young (1988; section PI of Askin et al. 
1971), at approximately the same level as the upper 
vertebrate assemblage at locality 11 of Young (1988, 
figure 5; section 10 of Barrett and Webb, 1973). 
Portal Mountain (fin-spines): CPC 21192, AMF 
55617 from units 26 and 17 may possibly belong to 
Portalodus gen. nov. (by association only). West of 
Mt Ritchie: CPC 21228, one tooth from locality 23 
of Young (1988). WAM 92.3.65, 92.3.66., "fish 
hotel" site B (Fault Bluff, Cook Mountains, Figure 
1). WAM 92.3.64, Mt Ritchie, middle horizon (new 
site 1991/92). WAM 94.2.12, "Gorgon's head" (near 
Mt Hughes), Cook Mountains. WAM 94.2.11, Mt 
Gudmundson (Cook Mountains), horizon 6. WAM 
94.2.7, Mt Crean (section 12, site MC7, Young 1988). 
Description 
These are the largest teeth yet recorded in 
Devonian sharks, the biggest specimen measuring 
2 cm in height from base of root to tip of crown 
(WAM 94.2.12; Figure 5C). Most specimens fall in 
the size range of 10-15 mm (maximum dimension). 
As originally described (Young 1982: 834, 835), 
these teeth were distinguished from Antarctilamna 
teeth by the unequal size of the cusps, the way the 
cusps were twisted in different planes in dorsal 
view, and in the opposite direction to the 
projection of the base, the absence of central 
cuspules, and the deeper, more bulbous base. Each 
cusp is rounded in section distally, but proximally 
the labial face is flattened, and separated from the 
more rounded lingual face by a fine ridge 
continuous between cusps. The labial face of the 
cusps is smooth (Figures 5A, D, F; 7A, C), but the 
lingual face (Figures 5B, C; 7D) normally carries 
two to four coarse striations (in contrast, a smooth 
lingual and striated labial surface is known in some 
other forms, e.g., Antarctilamna, ‘Phoebodus’ 
heslerorum; Williams 1985: 127). The base is 
normally notched in about the middle of its basal 
margin, in which a large foramen is seen in labial 
view (WAM 94.2.10, Figures 5B, 6C). The ventral 
surface of the base is shown in WAM 94.2.10 
(Figure 6C, also 7B, D). There is a large foramen 
placed near the lingual margin, and a well-defined 
ledge separating the lingual half of the base from 
the more concave labial half. The labially-projected 
division of the base has a weak outer ledge 
developed on the dorsal surface. The ventral 
surface is crossed by a shallow groove connected 
to the foramen on the labial surface (Figures 6 C, 
7B, D). 
Two fin-spines (CPC 21192, AMF 55617) 
associated with the teeth of Portalodus from the 
type locality were assigned to Antarctilamna prisca 
by Young (1982). However, it is possible that these 
belong to Portalodus, since Antarctilamna teeth have 
not been found at this locality and horizon (units 
