Extremely old, extremely large sperm and the sexual organ that propelled them. It's an awkward kind of scientific discovery but incredible nonetheless.
Australian researchers found "almost perfectly preserved" sperm cells curled up within the sexual organs of 17-million-year-old fossilized shrimp. Not only were the fossil sperm preserved but also the organ that sent those sperm into the female.
University of New South Wales researchers published word of their discovery Wednesday in the journal Proceedings of the Royal Society B. In a news release, they called these delights "the oldest fossilized sperm ever found in the geological record."
The scientists believe it was the bat poop at the fossil-rich Queensland site where the fossil shrimp were found that preserved the soft tissues of the shrimp so well for so many years. UNSW associate professor Suzanne Hand speculated in a news release that there may be "some magic ingredient in bat droppings."
The sperm were found in five specimens of the species Heterocypris collaris and Newnhamia mckenziana.
Researchers put the shrimp under a microscope and virtually peeled it -- seeing its internal sexual organs, and within those its preserved giant sperm cells, and within those its nuclei, which eons ago held the animals' DNA.
The shrimp are known as ostracods, which are among the creatures with the largest sperm in the animal kingdom. Some freshwater ostracods make sperm that's up to 10 times the length of the ostracod's body. The sperm in the ancient shrimp found by Aussie researchers were 1.3 millimeters long. (For the sake of comparison, the head of a human sperm has a width of 3.5 microns, or 0.0035 millimeters.)
What organism has the longest sperm cell? The Drosophila bifurca species of fruit fly is said to produce sperm that's 5.8 centimeters long.
Transferring such sperm, contained within tiny organisms, seems like a huge feat. But Mother Nature's genius is apparent with the Zenker organ, a muscular "sperm pump" that is highly effective at moving giant sperm from Point A to Point B. These fossilized organs were also observed, well preserved, in the tiny shrimp.
The researchers are celebrating their find at the Riversleigh site in Queensland. They said this rich fossil site has produced giant, toothed platypuses and flesh-eating kangaroos -- but minuscule shrimp with mega sperm? That was "totally unexpected."
Follow me at @AmyTheHub
Copyright © 2014, Los Angeles Timesvia Science - Google News http://ift.tt/1jviy0V
Put the internet to work for you.
No comments:
Post a Comment