Sometimes life is hard. Take today for example; it came time for me to compose my Friday post, so the first thing I do is look for a picture to go along with the subject.
I have mentioned this once before that I like to have a picture that might or might not let you know exactly what that subject is. More often than not, the picture has no obvious connection to the subject. But then the joke I add in the opening paragraph explains it. It's my way of trying to be clever. I think it works, but I'm biased.
And that's the reason I say life is hard, at least for today. As you all know, today is Friday. And last week I started a new weekly feature where I talk about fossils. And I even came up with a name for the days post. And that's why I used this picture.
Welcome to Friday Rocks!
I know. But have no fear, this won't become a permanent lead off picture for my Friday posts. I'm still trying to find one that I like. I've decided that, if I can find a suitable picture, I'll change it up on Fridays and use a standard picture, saving the pictures of the actual fossils for later in the posts. But that's all boring details no one really cares about. So let's move on to the real meat of the post.
One thing you may notice about a lot of fossils, especially the higher end, more detailed ones, is that they appear to be broken, and then repaired. Breaks on fossils are normal. In fact, it's one of the methods you can use to tell if you're looking at a real fossil, or a fake. (a real fossil will have any visible break go through both the fossil and the matrix it sits on. Also a real break looks different than a break that has been duplicated by casting, the most common method of fossil forgery)
Fossils are rocks. And, they are sometimes buried deep within the rocks. And to get them out, you have to break the part that contains the fossil away from the rest of the rock. (the materiel the fossil is contained in is called the matrix) The problem arises from the fact that, when you break open a piece of matrix, you may not know there's a fossil in there. And sometimes the fossil get's broken into pieces. Once the fossil containing matrix is separated, the pieces will be glued together and the fossil revealed.
This type of repair is fine. It doesn't really effect the value of the fossil. Sometimes, however, a piece of the fossil will be lost when it's being extracted, or maybe part of it didn't fossilize. Sometimes people will reconstruct the missing piece. Most people call this restoration. This can affect the value of the fossil. Some times it's common to find only pieces of the creature that was preserved. Whole specimens are rare. Sometimes a shady dealer will try to reconstruct a partial fossil to make it whole. If they are up front about it and tell you, that's fine. But many times they will try to pass off a restored fossil as a whole fossil.
This isn't to say restoring fossils is a bad thing. It is not. Trying to pass a restored fossil off as a completely natural fossil is. Far from being bad, most of the fossils people picture in their minds are almost 100% restored. Or they are outright fakes. But we'll get to that next week. Let's look at todays featured fossil, shall we?
This is a genus of marine reptile called Keichousaurus. This particular species is Hui. Keichousaurus lived during the Triassic period, (252 to 201 million years ago). These little reptiles were small, usually growing no bigger than 30-35 cm in length. They are also one of the more common species of marine reptile from the period to be found. Most are found as complete, articulated examples.
These little critters were long and sleek. Their streamlined bodies allowed them to swim through the water at fairly high speeds. Their long necks and sharp teeth meant they most likely subsided on a diet of small fish.
Discovery of broad ulna bones in the legs suggest keichousaurus might have spent some of it's time on land. However, since they've been dead for a couple hundred million years, it's hard to be sure.
Although they lived during the time of the dinosaurs, and despite the 'saurus' at the end of their name, keichousaurus were not dinosaurs. They were marine reptiles, very similar to the plesiosaur.* (also not a dinosaur)
One of the things that isn't known was how it reproduced. Most reptiles of this type are egg-layers. However, female specimens don't exhibit the ossification on the ulna bones that suggest they buried eggs. And some examples have been found where females had fetuses located in the lower thoracic cavity. These were in the wrong location to suggest cannibalism, but in the right area for a creature that gives live birth.
There really isn't a whole lot more about keichousaurus. They were first discovered in 1957, and described in 1958. The fact that we've only known about them for 60 years says a lot about the fossil record. This is a creature that lived for millions of years, and judging by the amount of fossils being found, they were very common in their era. Today you can pick up a very nice example for yourself for ~$200. This just shows that we have no idea what could still be buried under our feet. It's been estimated that 99.9% of all species of life that have existed has left no fossil record at all. There are just over 300 distinct genera of dinosaur that have been named. (genera is the step above species). Dinosaurs lived for 185 million years. How many more genera are left to be discovered?
The USGS says between 700 and 900. But that's just a guess. No one will ever know exactly how many genera of dinosaur there were. And that's just dinosaurs. They were by no means the only inhabitants of the planet at the time. There were fish, reptiles, mammals, insects, birds, arthropods, echinoderms, crustaceans, the list goes on and on.
* A Plesiosaur is the common suspect for the Loch Ness Monster. Since the keichousaurus is really similar to a plesiosaur, just a lot smaller, viewing one of these is about as close as you'll get to seeing Nessie.