Microscopic Creepy-Crawly Discovered By Ohio State Graduate Student
[ Watch the Video: Digging Up A New Mite Species ]
April Flowers for redOrbit.com – Your Universe Online
It may resemble a worm, but it’s actually a previously undiscovered microscopic species of mite discovered on The Ohio State University campus.
Discovered by Samuel Bolton, a graduate student at Ohio State, the mite was officially named Osperalycus tenerphagus (or as it is affectionately known – the “Buckeye Dragon Mite”). Osperalycus tenerphagus is Latin for “mouth purse” and “tender feeding,” referring to its complex and highly unusual oral structure.
Rather than the mythological winged dragon, the mite resembles the snake-like Chinese dancing dragons that appear in New Year festivals. It does not, however, resemble the typical mite, which is characterized by a large round body and tough external surface. The adult O. tenerphagus is just 600 microns, or just over half a millimeter and cannot be seen by the naked eye.
“It is incredibly intricate despite being the same size as some single-cell organisms,” Bolton, who is a doctoral student in evolution, ecology and organismal biology, told Ohio State’s Emily Caldwell. “That’s the fascinating thing about mites and arthropods – mites have taken the same primitive and complex form and structure that they’ve inherited and shrunken everything down. So we’re dealing with complexity at an incredibly small scale.” Bolton described his discovery online in the Journal of Natural History. O. tenerphagus is the fifth species from the worm-like family Nematalycidae to be described, and only the second in North America.
Initial examination of the mites collected from silty clay loam soil across the street from the acarology lab suggested that Bolton had discovered a novel species. Bolton collected his mites from a soil depth of about 20 inches. When he examined them under a compound microscope, he found that they had numerous straight hairs all along their bodies (known as setae) that didn’t match any of the known members of this family. The mites use these hairs to feel their way around.
Bolton was surprised to find the mites in a clay-like patch of earth as Nematalycidae are more closely linked to sandy soils. He thinks the key to finding the mites was digging 20 inches down.
Bolton was unable to learn all the details of his extraordinary find until a year later when he was able to examine the mite in a low-temperature scanning electron microscope (LT-SEM) run by the US Department of Agriculture.
Bolton used LT-SEM to capture high-resolution images of these tiny creatures. He marveled at the machinery of their mouths, which had structures called rutella, which typically function in a similar way to teeth in other mites. In these mites, the rutella instead support a pouch-like vessel in the front of the mouth. Bolton believes that the pouch acts like a nutcracker, holding microorganisms in place while the internal pincers puncture them and suck up their fluid contents.
To obtain images of mites of this size and body type, cold-temperature scanning is necessary so that they aren’t crushed by the intense vacuum effect of a normal electron microscope. The research team, which included Hans Klompen, professor of evolution, ecology and organismal biology at Ohio State, Gary Bauchan of the USDA Electron and Confocal Microscope Unit and Ronald Ochoa of the USDA Systematic Entomology Laboratory, used liquid nitrogen to freeze the mites immediately upon collection. This allowed the team to obtain images of the mites just as they appeared in their natural habitat.
They found that although the mite’s movement and muscle pattern do resemble a worm’s, it is unable to alter its diameter the way a worm can.
The mites have an external surface that resembles abacus beads. They “are like miniature accordions,” Bolton said. “It’s a case of convergent evolution – they have the same basic way of moving as worms, insofar as their cuticle extends and contracts, but they also have legs and, to some extent, still use them. The worm-like motion helps them move around through tight spaces.”
The Neatalycidae family of mites are the evolutionary descendants of ancient groups of mites whose fossils date back 400 million years, when the environment was arid throughout much of the world.
“They’re well adapted to living in extremely adverse environments – which makes them extremophiles. They’re also fascinating to look at, and are interesting for addressing ecological and evolutionary questions,” he said. “Because of their small size, there is very little understanding of how mites interact with their environment or other organisms.”
Bolton will continue his research by describing the mite’s complex oral structure, and he hopes to identify specifically what it uses for food.