Dicranurus monstrosus
Trilobite Order Lichida, Family Odontopleuridae
Geological Time: Lower Devonian
Size: 55 mm
Fossil Site: Laatchana Formation deposits near Alnif, Morocco
 Here
is one of the more sought after trilobites of the Order Lichida, Family
Odontopleuridae known as Dicranurus monstrosus. This particular example
is quite large at 55 mm in length from the dramatic cephalon to the
wonderful pleural spines, and has a "wingspan" of 2.6 inches
at the genal spines. Notice that the librigenae are tightly attached,
a sign of a well-articulated specimen. It is found in the Lower Devonian
Laatchana Formation deposits near Alnif, Morocco. It is quite prone,
and dominates its 2.7 inch by 2.9 inch bed of matrix. To me, the most
impressive features are the dramatically retorted occipital spines,
looking like ram's horns. In all, there are EIGHTEEN freestanding
spines present, making for an impressive display piece. To what purpose
could this spiny exoskeleton have been evolved? The answer is simple
-- DEFENSE!! Fish had recently evolved jaws, and in the never ending
arms race between predator and prey, Dicranurus' amswer was a spectacular
defensive array of spines. A substantial amount of prep time goes
into a dramatic specimen such as this. |
