Trimerus delphinocephalus Trilobite

I have now been collecting fossils in the Waldron Shale for several years and I have a short list of the rare fossils I want to find in my collecting lifetime. I call these elusive fossils the "Holy Grail" specimens. It is in reference to the King Arthur legends of his knights quest to find the cup Jesus used at the Last Supper. To me, a Grail fossil means a specimen that is extremely hard to find, if not impossible.

My "Holy Grail" Waldron Shale fossils to find are: intact prone position Bumastus trilobite, any type of blastoid, intact prone position Arctinerus trilobite, and an intact prone position Trimerus trilobite. While hunting with my young nephews (Perceval and Gawain, okay not their real names... joke), I almost achieved finding a Grail fossil.

Behold these pictures of an almost complete Trimerus delphinocephalus (Green, 1832) trilobite. It was fossilized intact but the tail (pygidium is missing and the front of the cephalon has broken off with the indentation left in the shale showing it was there at one time). Fossil was found in Clark County, Indiana in the Silurian age Waldron Shale. It has not been cleaned and photographed wet or partially wet.

It might not be that impossible to find this trilobite as I think, see one on the Week's trilobite web site.

Images taken with microscope of trilobite thorax sections.

Microscope images of scratch marks on thorax segment. Were they made when the trilobite was still alive? If so, by what?