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Name: Asaphus intermedius
trilobite,
with Echinosphaerites
Age: Middle
Ordovician
Size: mm (25.4mm=1
inch): 59 mm long by 34 mm wide with a 25 mm diameter cystoid on a 130
by 140 mm matrix.
Location: Asery Horizon
deposits of the Wolchow River region near Saint Petersburg, Russia
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 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 intermedius. The trilobite itself is 2.6 inches
long (measured in straight projection) and 1.6 inches wide at the
widest extent of the cephalon. There are two cystoids of the genus
Echinosphaerites 1.5 and 1.3 inches across present as well. Its
caramel-colored Calcite shell is well set off by the white limestone
matrix and gray shells of the cystoids. 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
(its eyestalks are intermediate between those of A.kotlukovi and
A. punctatus). As always, the skillful Russian preparators have
shown this fine specimen to best advantage, well-positioned on its
6.0 inch by 5.2 inch matrix.
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