Up until a few months ago, I had never, in my 50+ years of living, ever heard the word cleithrum (clei·thrum). In fact, my first attempts at pronouncing it were major fails. They ranged from
cle-RITH-thrum to cleee-thrum. I had to be corrected numerous times by our Junior Paleontologist, Jacob (a 7th Grader) at the Whiteside Museum of Natural History in Seymour, TX.
My introduction to a cleithrum came when I was assigned to prep a 287 million year-old fossil. This particular fossil was from an eyrops.
“Eryops was a common, prehistoric amphibian that lived in swamps during the Permian age, long before dinosaurs evolved. It was a carnivore and a fierce predator on ground and in the water and may have eaten regularly fish, little reptiles and amphibians. The amphibian would clutch its prey and, lacking any chewing mechanism, toss its head up and backwards, throwing the prey farther back into its mouth. Such feeding is seen nowadays in the crocodile and alligator… It had a fat body with very wide ribs, a strong spine, four short, burly legs, a short tail and a wide, elongated skull with various sharp teeth in large, strong jaws. Its teeth had enamel with a folded mold. Eryops was about 5 feet (1.5 meters) long, one of the biggest land animals of its time. It weighed about 200lbs. The skull of Eryops is proportionately big, being wide and flat and reaching lengths of 2 feet (60 cm).” More at rareresource.com
The cleithrum was a primitive b
one that lies along the scapula (shoulder blade). It looks like a pancake flipper. It helped form a massive shoulder structure which attached to large muscles that were needed to help move the large eryops along the ground.
Chris Flis, Whiteside’s Museum Director found this particular cleithrum at the end of 2015. He jacketed it and brought it back to our prep lab where it waited until the end of January for me to start prepping (more specifics on prepping on a later blog).I was able to find over 40 pieces of fossil fragments that I slowly cleaned, removed and glued back together to form a nearly complete cleithrum specimen (I still have around 10 fragments to attach).
So where is the cleithrum in our human body? You would think maybe somewhere next to our scapula, right? Wrong. I actually asked a trick question. It turns out that we do not have a cleithrum. No mammals do, but it is found in some modern day fish and frogs. It can actually be used to determine the age of fishes because each year the fish’s body adds a new layer to the bone.
It articulates with the skull. If we had two cleithra, our heads would not be able to turn separate from our shoulder. (Although as I get older, I sometimes wake up with this condition anyway.) I imagine that we’d all look like Admiral Ackbar from the Star Wars movie.
Today, some scientist believe that there is a ghost of the cleithrum that makes up the spine of the scapula, by researching the paleontology record and cell growth in embryos, but it is still under investigation.
So for now, I'll just go about my business of finishing the prepping of the cleithrum wondering what the eryops it belonged to was like when it roamed upon the earth.
Tracy Jon Houpt
Tracy is the volunteer Prep Lab Supervisor and Multimedia Specialist at the Whiteside Museum of Natural History.
The Whiteside Museum of Natural History is committed to inspiring enthusiasm and creating opportunities for discovering our present and ancient world and the immense cultural significance represented by the town of Seymour, Texas. The information provided to the community will be as accurate and up-to-date as possible and disseminated through the use of educational programming, fun interactive exhibits, growing and changing collections, and scientific research. With the goal to empower people to go forth and use their experience in future meaningful ways, the museum will in return be recognized as an innovative and healthy place of learning and research. The museum will strive to lead by example in demonstrating responsibility to the planet and its people through an ongoing commitment to green energy and conservancy, and will maintain ethical standards within the industry. These values will extend throughout the museum’s presence within the community and beyond.
Very interesting! Thank you for sharing this!
ReplyDelete