Gross morphology, length, curvature
From the sharp, elongated and nearly straight teeth of the ball python
(Python regius , Fig. 4), to the round, bulky and nearly flat
teeth of the king cobra (Ophiophagus hannah ; Fig. 4), the
morphological variability of dentary teeth in snakes is far larger than
what transpires from the literature. Yet, snake teeth remain easily
identifiable among vertebrates as they share some characteristics: they
are all conical, with various degrees of sharpness, and –although to
different degrees— posteriorly and medially curved (Fig. 2-5).
Variation in our curvature measurements appears to be driven by both
intrinsic and extrinsic factors. The mean and maximal degree of
curvature are significantly but weakly related to tooth length (Fig. 2).
They are positively correlated with one another; it was not obvious that
this relationship existed as the overall curvature can either be caused
by an elbow-like shape (high maxima of curvature, e.g., Homalopsis
buccata , Fig. 4) or a continuous curvature (high mean curvature, e.g.,Laticauda colubrina , Fig. 2). Yet, our results show that more
curved teeth also have a larger maximal angle of curvature and overall
straighter teeth have a smaller maximal angle of curvature. A posterior
tooth curvature may reduce the risk of breakage when the snake strikes
at high velocity and acceleration (Ryerson & Van Valkenburgh, 2021). An
increase in the curvature is associated with a decrease in the maximal
stress undergone by the teeth when out-of-plane forces are involved,
which is likely to be the case during a feeding sequence. The curvature
may also allow the prey to slide over the teeth into the mouth and to be
impaled if moving backwards, thus preventing a potential escape.