Illaenus sarsi  Jaanusson 1954 from the Kunda Level, Voybokalo Quarry, Near St. Petersberg, Russia.

Dates to the Lower Ordovician Period - In the region of 460-480 million years old.

The trilobite measures 5 cm (if outstretched) by 2.8 cm on a matrix 8.5 cm x 2.5 cm. The hard calcite exoskeleton shows up nicely against the lighter limestone matrix.