PORBEAGLES

In certain cases the two species of mackerel shark Cretolamna appendiculata and Archaeolamana kopingensis can look very similar. This is more prevalent as one moves backwards in the jaw to the lateral teeth.

Left - Cretolamna appendiculata
Right - Archaeolamana kopingensis
The root of A. kopingensis is more "U" shaped and the cusplets
more pointed than C. appendiculata.
Monmouth County, NJ

When viewed on profile Archaeolamana kopingensis (left)
 has a distinct lingual protuberance while the root and crown of
Cretolamna appendiculata is compressed. On lateral teeth this
protuberance is less pronounced but still present.
 

Top row— Archaeolamna kopingensis
Bottom row— Cretolamna appendiculata
Anterior, Lateral, Posterior
On lateral teeth the crown of  A. kopingensis curves,
while the crown on C. appendiculata is angled.
Scale 1 inch.