Please keep your photos coming in; I have a decent backlog, but you know how I worry. . .
Today we have some photos of fossilized wildlife, all taken by reader Mark Sturtevant. His notes are indented.
As a change from the usual stuff that I have been submitting, I thought to share pictures of some specimens that I keep in what I call my Cabinet of Mystery. Most objects are fossils or bones that I have either found or purchased over a lifetime.
I expect that a good percentage of humanity has at one time possessed a fossil fish known as Knightia from the Eocene Green River formation. But this Lagerstätten is also rich with other fossils. The first two pictures are of aquatic insect larvae from that location. Although it was labeled as tsetse fly larvae from the gem and mineral show where I picked this up, these are more likely horsefly larvae. The second picture is a close-up view showing the paired posterior spiracles that fly larvae often have, which in this case would have been used for breathing air while under water.
The second picture is a close-up view showing the paired posterior spiracles that fly larvae often have, which in this case would have been used for breathing air while under water.
I lived in San Diego for many years, and exposed areas of Quaternary sandstone are common over much of the area. While hiking in a park, I found this large fossil clam in a cliff about a mile inland from the ocean. I do not know the age, but it does strongly resemble a modern clam known as Tresus.
What is interesting about this specimen is that it appears that the clam had survived a serious injury which had healed.
The large fossil that follows was purchased, and it is a portion of a Cretaceous mollusk known as a Baculite. The total specimen would have been several feet long. I am a little mystified of their technical classification and anatomy (and so I would like to be corrected by any reader), but as I understand it these were a kind of shelled cephalopod, related to the modern chambered nautilus, only Baculite shells were straight instead of coiled. What is actually seen here is not really a preserved shell, which I think was paper thin and had dissolved away long ago. What remains is really a mold formed by sediments that infiltrated the interior of the shell after the animal died. One can still see that the shell was segmented into a series of chambers, and articulated together by intricate sutures. Some of the segments of rock actually wiggle a little, but are still locked together.
The Cabinet of Mystery also contains various skeletal remains. Here is a skull of an American opossum that I had since I was maybe 14. Through that time I would sometimes pick up road kill and learn what there was to learn of it by dissection in my bedroom/laboratory. With this one I eventually cut off the head, and waited for my parents to leave the house for the day so that I could boil the head in a pot on the stove, thereby making it a lot easier to remove the soft tissue. I am sure that I am not the only one who does not tell my parents everything! I do not know of many skeletal characters that identify a marsupial, although some obvious ones here are the small brain case and the numerous premolar and molar teeth. The spatters of paint were from a painting that I did of something many years later.