|
 Coming
from the Middle Ordovician Asery Level deposits of the Wolchow
River
region near Saint Petersburg, Russia, this is an example of the
trilobite Asaphus cornutus, and should come in a cage like the
Raptor
in Jurassic Park. The trilobite itself is 4.8 inches long  (measured
in straight projection) and 2.7 inches wide at the widest extent
of the cephalon, putting it at the high end of the size spectrum
(Yes, that round thing in the first photo IS a quarter!). Its
caramel-colored
Calcite shell is well set off by the white limestone matrix. The
genus Asaphus underwent some remarkable adaptations to changes
in
turbidity during the Ordovician, with this one presumably arising
in a time of increased turbidity, as evidence by the elevated
eye stalks. Asaphus punctatus and Asaphus latus
were
also
in that
same evolutionary
line. The right picture shows another cornutus less than 1/3rd
the length.
Also
see: Russian Trilobites Asaphid
Trilobites Russian
Ordovician Asaphus Trilobites Evolutionary Sequence |
