Rare Harpides plautini Russian trilobite

Coming from the Lower Ordovician Wolhovian Level deposits of the Wolchow River region near Saint Petersburg, Russia, this is an example of the trilobite Hapides plautini. It is a member of the Order Harpetida, a newly-erected order derived from the Ptychopariida. The trilobite itself is 25 mm long (measured along the curve) and 20 mm wide at the widest extent of the cephalon. Its coffee-au-lait-colored calcite shell is well set off by the white limestone matrix. The most distinctive feature of this trilobite is the broad finely textured cephalic ring that may have served to keep the trilobite at the surface of a silty bottom, much like snowshoes keep a hiker supported on snow. These trilobites are nearly always found as partials; a complete one with thorax and pygidium is almost unheard of.

Also see: Russian Trilobites