Picture a turtle the size of a Smart car, with a shell large enough to double as a kiddie pool. Paleontologists from North Carolina State University have found just such a specimen – the fossilized remains of a 60-million-year-old South American giant that lived in what is now Colombia.
The turtle in question is Carbonemys cofrinii, which means “coal turtle,” and is part of a group of side-necked turtles known as pelomedusoides. The fossil was named Carbonemys because it was discovered in 2005 in a coal mine that was part of northern Colombia’s Cerrejon formation. The specimen’s skull measures 24 centimeters, roughly the size of a regulation NFL football. The shell which was recovered nearby – and is believed to belong to the same species – measures 172 centimeters, or about 5 feet 7 inches, long. That’s the same height as Edwin Cadena, the NC State doctoral student who discovered the fossil.
“We had recovered smaller turtle specimens from the site. But after spending about four days working on uncovering the shell, I realized that this particular turtle was the biggest anyone had found in this area for this time period – and it gave us the first evidence of giantism in freshwater turtles,” Cadena says.
Smaller relatives of Carbonemys existed alongside dinosaurs. But the giant version appeared five million years after the dinosaurs vanished, during a period when giant varieties of many different reptiles – including Titanoboa cerrejonensis, the largest snake ever discovered – lived in this part of South America. Researchers believe that a combination of changes in the ecosystem, including fewer predators, a larger habitat area, plentiful food supply and climate changes, worked together to allow these giant species to survive.Carbonemys’ habitat would have resembled a much warmer modern-day Orinoco or Amazon River delta.
In addition to the turtle’s huge size, the fossil also shows that this particular turtle had massive, powerful jaws that would have enabled the omnivore to eat anything nearby – from mollusks to smaller turtles or even crocodiles.
Thus far, only one specimen of this size has been recovered. Dr. Dan Ksepka, NC State paleontologist and research associate at the North Carolina Museum of Natural Sciences, believes that this is because a turtle of this size would need a large territory in order to obtain enough food to survive. “It’s like having one big snapping turtle living in the middle of a lake,” says Ksepka, co-author of the paper describing the find. “That turtle survives because it has eaten all of the major competitors for resources. We found many bite-marked shells at this site that show crocodilians preyed on side-necked turtles. None would have bothered an adult Carbonemys, though – in fact smaller crocs would have been easy prey for this behemoth.”
Archive for May 20th, 2012
Posted by Xeno on May 20, 2012
Posted by Xeno on May 20, 2012
The MirageTable was demonstrated at a conference in Austin, Texas and is outlined on the firm’s research site.
Researchers said it could “fool” the eye to suggest both parties were using a “seamless 3D shared task space”.
The team admitted more work was needed before the system could be marketed. …
The MirageTable uses a 3D-video projector to beam images onto a sheet of curved white plastic placed in front of the user.
At each end one of Microsoft’s Kinect depth camera sensors is used to track the direction of each person’s gaze as well as to capture the shape and appearance of objects placed on the surface and the participant sitting behind them.
Users are also required to wear shutter glasses in order to see the projected image in three dimensions. Two computers linked by a network connection are required to power the experience.
The researchers said they were “motivated by a simple idea: can we enable the user to interact with 3D digital objects alongside real objects in the same physically realistic way and without wearing any additional trackers, gloves or gear.”
They claimed success stating that the experience was a significant improvement on current video conferencing technologies.
“In our system, the user can hold a virtual object, move it, or knock it down, since all virtual and real objects participate in a real-world physics simulation… The unique benefit of this setup is that two users share not only the 3D image of each other, but also the tabletop task space in front of them.”
A shows two people working at different locations to build an object out of blocks, with one researcher measuring the distance between the pieces placed by the other participant.
A research paper also noted that the technology could be used to create a single-person gaming experience.
It said that a scan of a single bowling pin could be used to create multiple objects projected in front of the user. These can then be knocked down with a virtual bowling ball using a physics simulation built into the system.
The researchers showed that the set-up could also be used to allow virtual reality bowling
However, the researchers admitted that the project was far from perfect.
At present the Kinect device only captures the front face of objects, leaving gaps and imperfect texturing. The technicians suggested that this could be fixed by using additional cameras.
The set-up also only allows users to scoop or catch objects from below in order to hold them in their hands.
“Simulating realistic grasping behaviours given depth camera input remains an open research problem,” the researchers admitted.