Category Archives: Palaeobiology/Palaeoanthropology
Lasers lock X-ray beams onto the remains of Clarisse, a 50-million-year-old snake. The fossil was scanned on a 64-slice CT scanner at The Methodist Hospital in Houston, and the resulting images were analyzed by Brazilian paleontologist Hussan Zaher. The snake is part of the collection at the Houston Museum of Natural Science and will go on display in 2012. (Credit: Photo by Denny Angelle/The Methodist Hospital System)
ScienceDaily (Sep. 20, 2010) — Even some of the most advanced technology in medicine couldn’t get Clarisse to give up all of her secrets. After all, she’s protected them for more than 50 million years.
Clarisse is a snake, found in the Fossil Butte region of Wyoming, perfectly fossilized in limestone and the only one of her kind known to be in existence. Palentologist Hussan Zaher came to Houston at the behest of the Museum of Natural Science to study her.
He brought the precious find to The Methodist Hospital and subjected her to a detailed CT (computerized tomography) scan in hopes of finding where Clarisse fits along the timeline of evolution.
“Most fossilized remains of snakes are individual pieces of bone,” said Zaher. “This is unique because it’s a complete snake, which gives us an opportunity to study her makeup and hopefully learn more about her.”
CT scan technician Pam Mager conducted the scan on a 64-slice scanner that is capable of sending laser-guided X-rays through a target. “We can take almost 3,000 images in less than a minute,” she explained, “and then we can use those images to construct a three-dimensional picture of the snake’s bone structure.”
Zaher, professor and curator of the collections of herpetology and paleontology at the Museu de Zoologia of the Universidade de São Paulo in Brazil, worked with the Museum of Natural Science in Houston to get Clarisse to Methodist for the scan. He believes Clarisse could be an evolutionary link between snakes who take a lot of small bites to eat their prey and snakes who swallow their prey whole.
The snake fossil was preserved in what is now limestone, and the entire chunk of rock was placed on the bed of the CT scanner. In less than a minute, the images were taken and assembled by computer into a three-dimensional image that could be rotated 360 degrees.
Taking a preliminary look at the images, Zaher said he saw no traces of limbs. “That places it higher up the evolutionary scale, but the snake is still very old,” he said. For more than an hour, he and technician Mager studied the images, looking at tiny details of the snake’s skull to find clues to how it may have eaten its prey.
Clarisse is the best preserved Caenozoic snake known in a U.S. scientific collection. According to preliminary analysis, this snake is believed to be closely related to Boavus indelmani, a booid snake described in the late 1930′s. Zaher and the Houston museum hoped that getting a look at the underside of this unique fossil, as well as the inside of bones like the skull would shed some light on the evolutionary history of the species, and its relationship to booid snakes (like pythons and boas).
“This is a very important step in studying this specimen … I will be able to take away copies of the images for further investigation and I believe this will help us learn about this snake,” Zaher said. “I cannot express my gratitude enough to (The Methodist Hospital) and the radiology services department here.”
The snake is part of the collection at the Houston Museum of Natural Science.
Methodist Hospital, Houston (2010, September 20). 50-million-year-old snake gets a CT scan. ScienceDaily. Retrieved October 13, 2010, from http://www.sciencedaily.com /releases/2010/09/100918212925.htm
The fossil specimen, with the trilobite towards the left, and the remains of the extremely rare plumulitid towards the right. Images below show a close up the plumulitid (actual size is 16 mm long), and a reconstruction of how it would have looked during life. (Credit: Fossil images by Jakob Vinther and David Rudkin, copyright Royal Ontario Museum / Reconstruction by Esben Horn, http://www.10tons.dk)
ScienceDaily (Mar. 18, 2010) — Scientists have unearthed the remains of one of the world’s rarest fossils — in downtown Ottawa, Canada. The 450-million-year-old fossil preserves the complete skeleton of a plumulitid machaeridian, one of only 8 such specimens known. Plumulitids were annelid worms — the group including earthworms, bristleworms and leeches, today found everywhere from the deepest sea to the soil in your yard — and although plumulitids were small they reveal important evidence of how this major group of organisms evolved.
“Such significant new fossils are generally discovered in remote or little studied areas of the globe, requiring difficult journeys and a bit of adventure to reach them,” notes Jakob Vinther of Yale University, lead author of the paper describing the specimen. “Not this one though. It was found in a place that has an address rather than map co-ordinates!” Plumulites canadensis, Albert Street, Ottawa, Canada K1P1A4.
The fossil is described by Vinther and Dave Rudkin, of Toronto’s Royal Ontario Museum, in the current issue of the journal Palaeontology.
It was Rudkin who first recognised its scientific significance: “This nifty little specimen first came to my notice when I received a letter from an amateur fossil collector in Nepean, Ontario. In prospecting for fossils in rock from a temporary building excavation he had turned up a small block containing a complete trilobite, but next to it was something else and he sent me a slightly fuzzy but very intriguing photo. The mystery fossil was clearly not another trilobite, and I although couldn’t be certain, I thought it might be some sort of annelid worm with broad, flattened scales. James, the collector, generously agreed to lend me the specimen and I realised immediately it was a complete, fully articulated machaeridian! The first I had ever seen.”
At that time it was not known that machaeridians were annelids. “James was happy to donate the specimen to the Royal Ontario Museum, in exchange for a promise that I’d someday publish his discovery.”
It was not until 2008 that Rudkin’s hunch was confirmed, when a team of palaeontologists, including Jakob Vinther, decribed new machaeridian fossils from remote mountain localities in Morocco, revealing their relationship to annelid worms. Rudkin and Vinther agreed to work together to interpret the Ottawa specimen, and it is the results of that collaboration that are published in the current Palaeontology.
Plumulitid machaeridians look like modern bristleworms, with stout walking limbs bearing long bundles of bristles, but on their back they carried a set of mineralized plates. According to Vinther, “the plates themselves were rigid, but they could move relative to one other, providing plumulitids with a protective body armour very similar to the flexible metal armour invented by humans 450 million years later. Machaeridian body armour is unique among annelids, and probably helped them to succeed as ubiquitous components of marine ecosystems for more than 200 million years.”
With the publication of this paper Rudkin is finally able to make good on his promise “It’s great to be able to acknowledge the collector,” says Rudkin, but there is a twist to this tale: the man who found the specimen has now gone missing. “Regrettably, I lost contact with James and numerous enquiries as to his whereabouts have come up empty. I hope he somehow gets wind of all this.”
- Vinther, J.; Rudkin, D. The first articulated specimen of Plumulites canadensis (Woodward, 1889) from the Upper Ordovician of Ontario, with a review of the anterior region of Plumulitidae (Annelida: Machaeridia). Palaeontology, 2010; 53 (2):