Name:
Illaenus schmidti var cliens Russian
trilobite
Age: Lower
Ordovician
Size
(25.4 mm = 1 inch): 90 mm long by 52 mm wide on a 75 by 48 mm matrix Location:
Asery Horizon deposits of the Wolchow River region near Saint Petersburg, Russia
This
is an example of the unusual trilobite Illaenus schmidti. Based upon the fact
that the freestanding genal spines are neither as long, nor as widely extended,
as some examples it is most likely an example of the variety cliens. The other
variety, cardinalis has flaring, elongated genals. Some think these may have been
an expression of sexual dimorphism. 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 plowing through the substrate in search of a meal. This one is
presented wrapped around its matrix which has a flattened base for display from
any aspect. | |