424 
A.M. De Pomeroy 
differ from Nostolepis sp. 1 and sp. 2 in the crown 
ornamentation. 
Description 
The crown is flat, rounded anteriorly and 
tapering posteriorly, with six subparallel ridges, 
the central two of which bifurcate at the anterior 
margin (Figure 3M). The neck is indented at 
anterior and posterior, with about six small holes 
at the posterior. The neck area is thickened 
laterally, extending into a rounded projection at 
each side of the scale where the neck joins the base. 
At the posterior comer, the lower edge of the neck 
dips to form a downward-curving arc (arrow in 
Figure 3N). The base is deeply convex, with the 
greatest depth towards the anterior end of the 
scale. Both length and width are approximately 0.6 
mm, and depth of the scale is approximately 0.4 
mm. Recovery of only three specimens precludes 
histological examination. 
Order Acanthodida Berg, 1940 
Family Acanthodidae Huxley, 1861 
Acanthoides Brotzen, 1934 
Diagnosis 
Acanthodian scales with smooth, glistening, 
usually more or less convex crown, translucent on 
edges, quadrangular to rhomboidal in outline, with 
short neck and thick, rounded inverted pyramidal 
base (Wells 1944:28). 
Acanthoides sp. 
Figures 30, P 
Material 
Eleven scales (QMF 31827 + ten others). 
Locality 
SD204/120 m; Papilio Formation. 
Stratigraphic level 
Givetian (Middle varcus Zone). 
Description 
The crown of the scales is flat and unomamented 
(Figure 3P), the pointed posterior edge extends 
beyond the base, and the anterior and lateral edges 
incline slightly ventrally. The neck is deep and 
indented, and the highly convex base is deepest 
towards the anterior of the scale (Figure 30). These 
scales, together with Nostolepis sp. 2 described 
above, are the smallest of the acanthodian scales 
recovered, with length and width 0.3-0.4 mm, and 
height about 0.2 mm. The better-preserved scales 
have a transparent honey-coloured crown and an 
opaque black base; other scales are totally black. 
Discussion 
Confusion has arisen in the literature between 
scales assigned to the genera Acanthodes Agassiz, 
1833 and Acanthoides Brotzen, 1934. Wells (1944) 
recognises Acanthoides as a form genus, distinct 
from the Carboniferous Acanthodes, whereas 
Denison (1979) acknowledges Acanthodes from the 
Carboniferous and Permian, but suggests that 
forms assigned to various species of Acanthoides 
are in fact synonymous with Gomphonchus Gross, 
1971 and possibly Nostolepis Pander, 1856. Storrs 
(1987: 365) and Turner (Boucot et al. 1989:572) 
discuss this problem. Turner suggesting that the 
whole classification of smooth-crowned 
acanthodian scales from the Middle Devonian 
needs revision. The scales described here are 
assigned to Acanthoides, using Wells's concept of a 
form genus for smooth-crowned scales considered 
too old to belong to the Carboniferous and Permian 
genus Acanthodes. 
The Broken River scales strongly resemble 
specimens named Acanthodes? dublinensis figured 
by Gross from the early Middle and late Late 
Devonian (1973, plate 27, figures 8-11 and 16-17), 
by Vieth from the Emsian and Eifelian (1980, plate 
8, figures 21-22), and by Storrs from the Givetian 
and Frasnian (1987, figures 5-6), although these 
illustrations more closely fit the description given 
by Wells (1944:29) for Acanthoides dublinensis than 
that by Stauffer (1938:442) for Acanthodes ? 
dublinensis. In Australia, the genus Acanthodes has 
been reported, but not described or figured, from 
the Middle Devonian of Broken River, and Early 
Carboniferous of Victoria and Queensland (Long 
and Turner 1984). Also from Australia are scales of 
Howittacanthus kentoni from the Frasnian Mt Howitt 
locality in eastern Victoria (Long 1986). These small 
scales have a flat unomamented crown and are 
morphologically indistinguishable from those of 
Acanthodes (Long 1986). 
Class Chondrichthyes Huxley, 1880 
Infraclass Elasmobranchii Bonaparte, 1838 
Order Cladoselachida Dean, 1894 
Family Cladoselachidae Dean, 1909 
Cladolepis Wells, 1944 
Cladolepis cf. gunnelli Wells, 1944 
Figures 4A-C 
These specimens have been described and 
discussed elsewhere (De Pomeroy 1994). They are 
included here because the range of this form at 
Broken River is longer than previously reported. 
Scales of Cladolepis cf. gunnelli Wells, 1944 
(Figures 4A-C) occur in Givetian to earliest 
Frasnian (Middle and Upper varcus, hermanni- 
