As I mentioned when in Portland, I encountered reader Bruce Thiel at my free will talk; Bruce’s avocation is preparing fantastic fossils that he finds locally. I’ve featured some of his preparations before; have a look, as I’ve never seen anything like them. Using a dental drill and working slowly and meticulously, he produces fossils like the ones below, whose photos just arrived in my email. (Go here to see how a preparation proceeds.) He doesn’t sell them, though preparations like this fetch high prices; instead, Bruce gives them to museums and scientists to study. So let’s have a paleontological “readers’ wildlife” today. Bruce’s notes are indented:
Here are some other interesting crabs I’ve prepared. Background information about the fossils and the discovery and preparation procedure can be found here [JAC: the second link above].
All the crabs shown are about 30 million years old and are Pulalius vulgaris, except for the last picture. This crab in the next two pictures was mashed and not particularly well-preserved—until I got to the eyestalks and claws, so I went as close as I could between the claws. The eyestalks are 1.5cm apart–slightly over 1/2 inch—so there was not a lot of working area.
The next crab was one of three given to the Smithsonian. What looks like googly-eyes are two attached barnacles.
The next two crabs host tube worms, and are at Kent State being studied for epibionts. The chip in the middle of the carapace is what fossils preparers call “the mark of discovery.” Most of the round or oval-shaped concretions are blank or contain bits of wood, shell or decomposed organic material. In working down into the middle of the rock with the pneumatic jackhammer to see what they contain, if one is too aggressive or not paying close attention, one can “nick” the shell with the pneumatic tool as I did in this case. Both crabs have interesting snake-shaped worms lurking on their shell. One of the questions experts would like to answr is if the worms attach while the crab was alive or after death and during decomposition.
This is one of the smaller crabs I’ve worked on. I held my breath when uncovering the tiny claw. My thumbnail is shown for comparison.
These are two Macroacaena schencki crabs from the Keasey Formation, Oregon (33 – 35 MYO). We think the larger and wider of the two is female but determination awaits further research.