Trapped in amber. Nearly five times longer than the life form from which it originated, a 1 mm ostracod.
Not only was finding the sperm surprising, but so was how much sperm was in the female. Modern ostracods produce the largest volume of spermatozoa in the animal kingdom. As it turns out, ancient ostracods also produced really large sperm a hundred million years ago.
Max Kozlov, “Unearthed: World’s Oldest Animal Sperm—And It’s Giant” at The Scientist
Paper. (paywall)
It would be interesting to know if there is any significance to the size of the sperm in terms of genetic transmission.
More amber stories
Amber—a moment in time 100 mya Life forms trapped in amber—hardened resin from conifers—can show remarkable examples of stasis: No real change from one ten-million-year span to the next one.
Millipedes Found In 100 Mya Amber Comprise 13 Of 16 Known Groups
Beetle trapped in amber 99 mya offers window into prehistoric ecology So, in another instance of “earlier than thought,” pollination seems to have preceded flowering plants.
Spider in amber is 49 million-year-old member of living genus
Stasis: Dinosaur-era baby snake looks just like modern ones
“Live action” captured in a spider’s web from 100 million years ago
How did 20-30 myo salamander in amber get IN there?