50-million-year-old fossil sperm discovered | Science News

ADVERTISEMENT

SUPPORT SCIENCE NEWS

Science News is a nonprofit.

Help us keep you informed.


The –est

50-million-year-old fossil sperm discovered

World’s oldest sperm may have come from a leechlike worm

By
7:05pm, July 14, 2015
ancient sperm

ANCIENT SPERM  The elongated head and whiplike tail of one of many apparent worm sperm cells studs the wall of a 50-million-year-old cocoon. 

Worm sperm have staying power. Embedded in the wall of a fossilized cocoon, mineralized sperm from what may have been a leechlike worm have stuck around for about 50 million years.

The ancient sperm fossils are the oldest yet reported. They predate the previous record holders — amber-preserved sperm from tiny jumping insects called springtails and petrified sperm from mussel shrimps — by at least 10 million years.

Researchers discovered the cocoon-entombed worm sperm by sifting through sediments from an Antarctic island. The cells’ drill bit–shaped heads and grainy texture resemble the sperm of Branchiobdellida, a group of squiggly little worms that crawl on freshwater crayfish today.

Sperm are short-lived and fragile, so preservation happens only rarely. But cocoons may offer an untapped resource for finding soft and delicate cells, and even tiny organisms,

This article is only available to Science News subscribers. Already a subscriber? Log in now. Or subscribe today for full access.

Get Science News headlines by e-mail.

More from Science News

From the Nature Index Paid Content