Andy Bentley removes specimens from a cryogenic dewar.
The KU Biodiversity Institute stores thousands of tissue samples from species found around the globe at a frosty -175 degrees Celsius. The specimens are stored in dewars, which are large, vacuum-sealed containers with a pool of liquid nitrogen at the bottom. While -175 degrees is hard to imagine, the newest dewar at KU dips even lower.
“The latest one we’ve acquired runs at -190 degrees Celsius, but otherwise functions much in the same way,” said KU Ichthyology Collections Manager Andy Bentley.
East Antarctica, warmer than a cryogenic dewar.
Tissues preserved in the dewars are in constant demand. Researchers from all over the world review online catalogs of stored specimens and send requests for tissues that could further their research. Upon receiving a request, the specimen is carefully extracted from the dewar and thawed on ice. Once thawed, a tiny piece of tissue is sliced from the sample and shipped in ninety-five percent ethanol.
The number and variety of specimens available for research is growing rapidly. The two dewars currently used are quickly filling with tissue samples. Bentley expects the newest dewar to see use before 2017.
“There’s new material coming in from the field at a rate of ten percent a year,” Bentley said. “In ichthyology we expect another 1,100 tissues a year, so with that kind of growth across all departments we expect to fill the two current dewars in six to eight months.”
When the first two dewars near capacity, the third will be filled with eight-to-ten inches of liquid nitrogen. This level is monitored 24 hours a day to maintain the crucially cold temperatures. Once filled, the third dewar stands ready to support the growing collection.
“There is a fairly large portion of material that is unique to our collection,” Bentley said. “The ichthyology collection, we think, is probably one of the largest ichthyology tissue collections in the world, based on taxonomic and geographic scope.”
A fisherman in southwest China stumbled upon a 200-year-old Chinese giant salamander weighing over 100 pounds. The four-and-a-half foot long specimen greatly surpasses the average lifespan of the critically endangered species. Giant salamanders are thought to live 80 years in the wild. The salamander found in China has been transferred to a research facility for study.
An adult Japanese Giant Salamander(Andrias japonicas).
Species of the giant salamander are found in both China (Andrias davidianus) and Japan (Andrias japonicas). Oddly enough, the closest relative to these living fossils is the Hellbender (Cryptobranchus alleganiensis) found in eastern North America. The hellbender, on average, grows to half the size of the giant species. KU Herpetology Collections Manager Luke Welton says giant salamanders diverged from the hellbender 65 million years ago.
Despite the distance between their homes, all three species have similar habitats and lifestyles. Welton says the three species spend little time on land due to poorly developed lungs, and instead absorb most of their oxygen through folds of skin on their sides. As a result of this preference, all three prefer cold, fast-running streams and lakes. Salamanders often seek refuge beneath large submerged rocks and boulders.
Several specimens of the hellbender and both species of giant salamander are part of the KU Biodiversity Institute Herpetology Collections.
A KU Herpetology lab snaps a selfie before releasing a hellbender found in the Niangua river near Bennet Springs, Missouri.
Salamander, Luke Welton, China, Herpetology
This Thanksgiving, don’t think of the yearly tradition as just carving up a turkey. In reality, you’re dissecting your very own dinosaur.
KU Paleontologist David Burnham studies ancient raptors of all sizes. Studying these ancient relatives fills the gaps between raptors of the past and the turkeys we eat today. Upon studying this lineage, one can see that turkeys and raptors have much more in common than you may think, despite differences in how we traditionally picture a “bird.”
“The public’s perception of what a bird may be might not be the definition a scientist would use,” said Burnham.
The public largely defines birds by their feathers and flight capabilities. By comparison to their ancestors, not only do both prehistoric raptors and modern birds share feathers, but many living birds also either rarely or never use flight including ostriches, emus, cassowaries and turkeys.
“The loss of flight has evolved several times throughout that lineage,” said Burnham. “If we want to draw a line when theropod dinosaurs became strictly avian, well, we’re still refining that even today due to the enormous amount of new discoveries.”
What’s important to remember is that dinosaurs never fully became extinct. The ones that survived mass extinction merely changed. Birds such as turkeys and chickens share their lineage with theropods, or two-legged meat-eating dinosaurs. The skeletal structures of turkeys and extinct theropods such as Velociraptor, Bambiraptor and Microraptor retain several similarities in particular.
Here are some points to look for while dissecting your “dinosaur” this Thanksgiving:
- Wishbone - The furcula, or wishbone, is a major connection between the turkey and its ancient theropod ancestors. The furcula is made up of two formerly separate collarbones, fused together. This evolutionary change aided in flight capabilities of ancient raptors such as Microraptor, and continues to help modern birds, such as turkeys, reach liftoff.
- Wings - The turkey wing deserves careful inspection. The fleshed-over tip is where claws protruded from theropod arms such as those of Velociraptor, Bambiraptor, and even the massive Dakotaraptor. Imagine those on your dinner plate! As theropod dinosaurs evolved, their arms became longer and those claws were covered by flesh forming wings suitable for extended flight – an easily recognizable feature of avian species we see today.
- Thighs and drumsticks - These are often the most sought after pieces of the feast, and still quite similar to the legs of theropods. This leg structure allowed raptors to reach impressive ground speeds; Velociraptor is thought to have been able to run as fast as 40 miles per hour! The turkey on your table is no slowpoke either thanks to this ancient design, with a top running speed of 25 miles per hour.
While the turkey still possesses many remarkable features harkening back to its raptor relatives, there are some things we can be thankful were lost during evolution.
“Of course, turkeys don’t have teeth,” said Burnham, “and that’s probably a good thing.”
vertebrate-paleontology, David Burnham, turkey, museum