This
is an example of the unusual trilobite Illaenus tauricornis. This is one of the
50-odd members of the genus, and known for the high profile of the cephalon which
is thought to have aided the trilobite in ploughing through the substrate in search
of a meal. It is also one of the more dramatic members of the genus, with recurved
genal spines. Indeed, the species epithet means "bull-horned", a quite
appropriate term for this example, which is of the variety thallosus by virtue
of the shape of the genals and pygidium. Typically, the large cephalon is pulled
under, probably as a result of the contraction of muscles as the trilobite died.
This one, however, is quite prone, with the genals prepared freestanding, making
for a dramatic and uncommon presentation of this unusual taxon. |