New groenlandaspidid arthrodire from Antarctica 
37 
Figure 2 Boomeraspis goujeti gen. et sp. nov. A, 
paratype right PVL plate, WAM 93.7.4.; B, 
holotype right PDL plate, WAM 93.7.2; C, 
paratype right PL plate, WAM 93.7.3; All are 
latex peels whitened with ammonium 
chloride, xl.5. 
inflection on the main lateral-line canal groove; PL 
has a prominent transverse ridge which becomes 
deeper anteriorly. Ornament on the PDL is of 
vertically directed rows of fine tubercles near the 
dorsal margin. 
Remarks 
Although known from only fragmentary material 
Boomeraspis is referred to the Groenlandaspididae 
because of the highly convex dorsal margin and 
inflected main lateral line canal on the PDL plate. It 
differs from the only other two known members of 
the family by its proportionately larger, strongly 
ridged PL plate, and the fact that the PDL is more 
elongated rostrocaudally compared with the 
narrow, higher PDLs seen in Groenlandaspis and 
Tiaraspis. The trunk plates described here are not 
considered likely to belong to Antarctaspis White 
1968 because this genus has been referred to as a 
stem-group phyllolepid (Long 1984; Young 1991) 
and, based on these cranial similarities, the 
corresponding trunk-shield would be expected to 
be quite unlike that of groenlandaspidid 
arthrodires. Nor is Boomeraspis likely to be 
confused with Antardolepis White, 1968 because the 
single plate of that genus, an AL, lacks a prominent 
lateral ridge that would be present on the AL of 
Boomeraspis as it has a prominent lateral ridge 
running anteriorly off the PL plate. Ritchie (1975) 
notes that Antardolepis appears quite distinct in its 
AL plate from that of Groenlandaspis, and is 
therefore not likely to be confused with other 
members of that family. 
Etymology 
The generic name is after the locality 
(Boomerange Range) and the Greek "aspis" 
meaning "shield". 
Figure 3 Boomeraspis goujeti gen. et sp. nov. A, B, right 
PDL plate, WAM 93.7.2 (holotype). A, lateral 
view; B, cross-sectional shape of external 
surface as indicated on A (internal surface 
unknown). B, right PL plate in lateral view 
(paratype WAM 93.7.3). 
Boomeraspis goujeti sp. nov. 
Figures 2-5, 6B 
Diagnosis 
Same as for genus. 
Type material 
Holotype WAM 93.7.2, an impression of the 
external surface of a complete right PDL plate 
(Figures 2B; 3A, B). Paratypes WAM 93.7.3, a 
complete right PL plate (part and counterpart; 
Figures 2C, 3C); WAM 93.7.4, a complete right PVL 
plate (part and counterpart; Figure 2A); WAM 
93.7.5, an incomplete posterior division of a spinal 
plate (mostly impression only; Figure 4). 
Etymology 
The species name is for Dr Daniel Goujet of the 
Musee d'Histoire naturelle in Paris, for his 
contributions to arthrodire studies. 
Locality and age 
The specimens all come from a dark green 
laminated mudstone occurring immediately above 
the first thick bluff-forming sandstone unit, 
approximately 30 metres from the base of the Aztec 
Siltstone exposed along the southeastern spur of 
Alligator Ridge (locality 21 of Young 1988). All the 
specimens were found close together in loose slabs 
of mudstone scree on top of the outcrop. As all the 
plates are from the right side, and are of correct 
size to fit together, it is quite possible that they are 
