The pelvic fin, although rudimentary, protrudes prominently
from the ventral contour of the body. The apparatus as exposed
is seen in dorsoventral view (Figure 3) and, therefore, its
bilateral symmetry is clear, especially with the clay-like matrix
having been carefully removed from along its length. The bony
element appears to represent the consolidation of the right and
left pelvic spines, as it is a continuous, solid, uninterrupted
piece without cross-striations (segmentations) or branching as
would be found in a soft ray. The two halves of the spine are
fully fused to one another medially except at the distal end.
Indentations and irregularities medially along the length of the
spine also are evidence of the region of fusion. Strong spiny
processes are present along its lateral edges, the more distal of
which tend to be retrorse. These spiny processes appear to be
fully continuous outgrowths of the spine itself. The base of the
pelvic spine abuts against the enlarged scale plate at the
posterior end of the ventrolateral ridge along the body armor.
At the end of the ventrolateral ridge this scale plate curves
medially to meet the base of the spine and presumably overlies
the posterior end of the pelvic girdle where the spine would
probably be attached. Just above the base of the pelvic spine the
body is indented, undoubtedly for the anus. There is no
evidence of elongate scales between the anus and the base of
the spine, such as those in Recent and fossil balistids that
strengthen the somewhat expansible dewlap or fan of skin in
this region. Neither is there evidence of a distinct series of
scales forming a sheath around the pelvic spine.
The lower jaw teeth are bluntly conical, slightly curved
posteriorly toward the distal end, and twice as long as those of
the upper jaw. The first four teeth on the side of the jaw are
clearly indicated (the second and third by impressions only)
and are of about similar length and width, while the few more
posterior teeth (probably two) apparently decrease in size
(these are not so evident as the first four). The upper jaw teeth
are more numerous, with about eight teeth clearly evident in a
single row. At least some of the upper jaw teeth, especially
those toward the middle of the series, have more constricted
distal regions than in the lower jaw, forming blunt nipples. In
neither jaw is there evidence of inner series teeth, although such
teeth, especially if small, could be hidden behind the large outer
teeth.