> It is especially suspicious that only the longest, sharpest, and
> most "fang-like" teeth have grooves.
Of course, long knives have grooves, but they aren't for venom
delivery (or the other misconception, that they work the other way
around, to let blood come out while the knife is still in). This may
simply be a weight saving feature, as with human designed knives
(although often the grooves aren't to impart I-beam like
strength/weight ratios, but rather they do it just for aesthetic
appeal) The entire skull does look rather lightly built. The longest
teeth would need the most strength to keep from breaking, so a groove
on the longest teeth makes sense if you only wanted to reduce weight.