Ancient whale species sheds light on shift from limb- to tail-powered swimming

DEC. 20, 2019 / 4:06 PM

By Brooks Hays

Dec. 20 (UPI) -- Modern whales use their tails to swim, but their earliest ancestors, a group of semi-aquatic species known as protocetids, swam with their limbs.

Due to gaps in the fossil record, the transition from limb- to tail-powered locomotion among whales isn't well-understood. But a newly discovered species of ancient whale, unearthed in Egypt, has offered scientists some clarity on the matter.

"The biggest gap is that we lack associated skeletons of whale intermediates between land mammals and the earliest of early known whales to document the transition to foot-powered swimming," researcher Philip Gingerich, professor of earth sciences, evolutionary biology and anthropology at the University of Michigan, told UPI in an email. "We also need more late middle Eocene skeletons to fully document the transition to tail-powered swimming."

The protocetid species Aegicetus gehennae -- newly named and described this month in the journal PLOS One -- has helped scientists begin the fill in the latter of the two gaps.

More:
https://www.upi.com/Science_News/2019/12/20/Ancient-whale-species-sheds-light-on-shift-from-limb-to-tail-powered-swimming/7921576869437/?sl=1&ur3=1