As a last flexing of my Congressional Fellow’s muscles, I arranged for a behind-the-scenes tour of the Paleobiology Department at the Smithsonian Natural History Museum. Translated, that means Dinosaurs! I timed the tour to coincide with the visit from my Beloved Husband and Darling Daughters (DDs), and I intend to include this outing on my “Stepmom of the Year” application.
For all the exhibit space available at the Natural History Museum, the laboratory and collection space is twice as expansive. Our guide told us how many total items and objects are owned by the Smithsonian, and my memory is that out of some 135 million items, 123 million are part of the natural history collection. Of course the Hope Diamond and the Wright flyer each count as one item, but that’s still a lot of storage space required. There are a number of satellite facilities for conservation and research, but there is still a need for large amounts of storage space.
Inside the paleobiology department, we paused by an alcove that formerly held a telephone booth. After the booth was removed, the alcove remained, and it became a display for items left over from the annual holiday Yankee swap or White elephant exchange. The collection has been embellished over time, creating a truly eclectic mix of objects, and I could tell that yet again, I had found a group of nerds who loved their jobs and shared a great spirit of fun.
We spent quite a bit of time hanging out with some Triceratops skulls. Our guide pointed out that paleontologists almost never find complete skeletons and even the collection of five skulls that we saw were all partial in one way or another. It often requires multiple specimens to get a complete picture of an animal. The Triceratops, itself, is an interesting example of the difficulties caused by multiple incomplete fossil sets. The earliest skeletons that were assembled eventually turned out to be a mixture of bones from more than one different species, so several of the earliest Triceratops species names are no longer valid. The DD’s nodded wisely while the responses of the Ph.D.’s ranged from a questing look as we dredged up hearing rumors of such a thing to surprise as we were told that perhaps we hadn’t learned the whole dinosaur story when we were young.
Paleobiologists are particularly challenged by the constantly evolving naming system in their field. An ongoing challenge is to differentiate between samples of different species vs. samples that display the normal variation that appears within a single species. As a result, species names are regularly added or retired when it is determined that what had been original designated as a unique species is really a variant on an existing species. This was the fate of the Brontosaurus, one of the other dinosaurs I learned as a child. I believe it was determined to actually be the same species as an Apatosaurus, and the earlier species name is always kept. When a new species is determined, a single physical sample is designated as a holotype, which is the ideal or reference fossil for the species. It is virtually always the best sample available, but once it is designated, the holotype remains that same sample, regardless of later finds of better quality samples.
Within the paleobiology department’s storage area, the open shelves held a bewildering array of casts and fossils interspersed with a generous collection of “clam-shells.” These padded cases are constructed to cushion fragile bones for transportation or even for just turning the bone upside down. As part of this information, I encountered a new occupation of “preparator.” Apparently specific to science, a preparator gets samples for study, and this work is extensive for fossils. Part of the preparator’s work is the construction of the clamshells. A bone is placed in a sand box to cushion it evenly, and then the top is padded, followed by the application of fiberglass strips and high quality dental enamel. For the bigger structures, rods are added to use as handles. Then the process is repeated on the other side. The two sides of the clamshell are bolted together to secure the fossil, and from that point on even when the sample is simply flipped upside down, it is first bolted into the clamshell. Apparently little bits still fall off the fossil sometimes, but the damage is minimized.
Because our guide specializes in ancient whales, we spent quite a bit of time talking about the skull of an early baleen whale. I was very grateful and proud to have the DD’s with us since the Ph.D.’s in the group ran strongly to chemistry and fluvial geomorphology (rivers) rather than biology. The DD’s displayed a far greater mastery of fossils, dinosaurs, and biology than the more highly degreed members of the group. When asked, one of the DD’s was able to speak knowledgably about baleen whales filtering water through their baleen, and it was agreed that modern baleen whales lack teeth. Thus the fossil we examined was an important link in the evolution of the whales since the bone structure clearly identified it as a baleen whale, but there were equally obvious holes in the skull for teeth. I was proud that one of the DD’s and not one of the Ph.D.’s was chosen to flip the skull over in its clamshell, and she performed like a pro.
The fossilized sample of a whirl of teeth was presented as another challenge. Since a fish did not randomly decide to arrange its teeth in an attractive and extremely regular spiral pattern to make a fossil after it died, this spiral pattern must have been part of the fish’s anatomy. We were shown half a dozen pictures of ideas generated by various scientists, but there has been no firm conclusion at this point.
When asked how he went into paleobiology, our guide pointed out that virtually all children are into dinosaurs at some point. Indeed, our behind-the-scenes tour was a wonderful combination of nerding out and channeling our inner five-year-olds. A magnificent time was had by the Ph.D.’s and DD’s alike.