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.
Fantastic
Yes, it’s like being a natural sculptor.
This are great — a very generous use of your time and effort.
Wow. I see that there are generally a couple legs cut off by the edge of the nodule. Are the ends of these legs visible on the surface, so to give one a clue of a treasure inside?
Good question, thanks Mark. A concretion found in a stream bed that comes loose from the bedrock, sometimes tumbles and wears down, so parts close to the edge are eroded. Sometimes most of the crab is worn away. If you look closely around the edge of the concretion, you might see hints of a leg, and it helps one determine which side is up and where the crab is located and one can follow the leg inward. I have some interesting prepared concretions where much of the crab was worn away. They may be on Facebook.
Fabulous work, Bruce. I can’t imagine the time and dedication required to accomplish all of this!
+ 1
Magnificent work, clearly a labor of love. His patience is only exceeded by his generosity.
I’ve found tube worms exactly like those on the shells of small scallops that I buy at the local supermarket here in Tokyo. They freak me out a little, so I make sure to scrape them off before I cook the scallops. I imagine that the tube worms would have become quite established while the scallops were growing, since the scallops are very fresh, often still alive, when I buy them.
I was thinking on this too. I’ve certainly seen serpulids attached to molluscs of various sorts, which are “infaunal” (live in or on sediment, and frequently don’t move their holdfast during adult life, even if they can move around the holdfast), but I haven’t particularly noted having seen them in “benthonic” species, such as scallops, which are somewhat motile on the sea floor. Likewise, I haven’t noted them – or their absence – on tests (“shells”) of fully mobile animal such as crabs.
I’ll keep my eyes open on that point in future beach-squelching.
Probably relevant : if whales (a very motile taxon, almost like a bear) can have their skin colonised by barnacles, then I don’t see any profound problem with serpulids colonising crustaceans.
If the crab was alive, would it scrape the tube worms or parasites away with it claw, if it could reach or see them? Were they edible and would they pick them off each other, like grooming chimps, if in close proximity?
They might. But those tubes are armoured defensive retreats – calcite cemented IIRC – and pretty tough. Would it be worth the effort?
Just echoing the above, remarkable stuff.
Reminds you of whichever famous sculptor it was, saying something like he just removed the bits that weren’t needed from around the statue.
I wonder how long it would take to prepare a full-size T-rex like that?
Well, the “Sue” specimen took several years to be sufficiently prepared to become a real bone (sorry!) of contention … which gives you an answer to some degree. Of course, most larger fossils come out of the ground in a number of slabs, because of the logistical difficulties of moving 40 or 80 tonne lumps of rock in remote field locations. Skyhooks can only lift so much.
“I saw the angel in the marble and carved until I set him free.”
These are marvelous. Since, “30-40 million years ago, parts of Oregon and Washington were underwater”, I’m wondering if there are other fossilized critters among the Crabs?
I wonder too, how closely these resemble modern crabs?
A few years ago while hiking up a stream bed I came across a fresh slide exposing 3 concretions. When I broke them open they contained hollow bones, which indicated they were from a bird. I packed them out and sent them to Gerald Mayr in Frankfort, a world expert on fossil birds and they were part of an extinct plotopterid–large flightless seabird—new genus, new species-Olympidytes thieli. They were just published last week in the Journal of Vertebrate Paleontology.
Wow! How cool. Your eyesight must be good!
Thanks, eyesight ok but it helps to have a good binocular microscope on a boom with fiber optic illuminators, to use for the prep work.
That sounds like ever amateur paleontologist’s dream — discovering a new species and having it named after him. And and just any boring, hard-bodied species, but a bird! My understanding is that bird fossils are relatively rare. Well done.
Wow! I always enjoy the wildlife pics, but this deviation is fantastic! Bruce has some serious talent, thanks for sharing!!
Those are wonderful specimens!
Beautiful work, Bruce! Wow!
Wow! These are stunningly beautiful! Thanks so much for sharing them with us. I am in awe.
Very impressive, awe-inspiring! Thanks for sharing Bruce.
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They’re all exquisite, but I was especially intrigued by the Macroacaena specimens. The carapace looks so different from most crabs I’m used to seeing (US Gulf Coast and Pacific NW coast). Are there modern crab species that are closely related, or resemble the fossil Macroacaena?
Thanks everyone above for your kind remarks and encouraging comments above! You WEIT readers are always so polite and considerate! The Macrocaena crabs are en extinct crab that are part of the Raninidae family. Please keep in mind that I’m an amateur, but there is some resemblance to the modern Ranina crabs—more in the frog-like flippers and the claws, but I’m unaware of any extant ones that have the two long side-extending spines. I think they were trying to make themselves hard to swallow.
Bruce’s preparations are truly spectacular. I can’t get tired of looking at them. Is like the crabs were about to start running away!
About the fossil frog crab, it belongs to an extant superfamily of frog-looking crabs called Raninoidea. This superfamily has two extant families: Lyreididae, and Raninidae. The extinct genus Macroacaena —the sole member of its own subfamily Macroacaeninae— belongs to the family Lyreididae. And yes, as Bruce pointed out, those long spines likely made themselves pretty hard to swallow. No extant lyreidid or raninid has spines like those of Macroacaena. Hope this helps. Best wishes
the detail is incredible
is it rare for a fossil to preserve that much structure?
Concretions containing fossil crabs in the Pacific NW have fairly good preservation—please keep in mind that the pictures represent only the very best examples. Some of Pulalius crabs have a thick shell that holds up well, structurally and are usually not hollow but have sand, or volcanic ash pressed into all the limbs during compression or formation. There are just as many or more fossil crab concretions found with paper-thin shell fragments that would flake away, or what we call a “crab kit”—a concretion containing unidentified parts of legs, claws and shell fragments all mashed and jumbled together along with sticks and unidentified mineralized organic material—the stuff you see swirling around the tide pools. Which leads into the question, will ocean concretions millions of years from now contain mostly plastic detritus mixed with organics after the great human extinction?