Date: 24/12/2023 16:56:25
From: Bogsnorkler
ID: 2106753
Subject: 19MY Whale jaw fossil
https://www.sciencealert.com/19-million-year-old-jaw-bone-flips-our-understanding-of-how-the-biggest-whales-evolved
https://www.sciencealert.com/19-million-year-old-jaw-bone-flips-our-understanding-of-how-the-biggest-whales-evolved
Bogsnorkler said:
https://www.sciencealert.com/19-million-year-old-jaw-bone-flips-our-understanding-of-how-the-biggest-whales-evolved
Ta.
Michael V said:
Bogsnorkler said:
https://www.sciencealert.com/19-million-year-old-jaw-bone-flips-our-understanding-of-how-the-biggest-whales-evolvedTa.
Surely DNA sequencing has already given us both a divergence date between baleen whales and toothed whales and …
Hold on, are there any small baleen whales? The pigmy right whale is 6.5 metres long. But it probably downsized from larger ancestors, right?
The common ancestor of toothed and baleen whales lived approx 40 million years ago.
According to myoglobin evolution (not a reliable guide on its own) the bowhead whale is one of the most ancient. The longest reliably measured male bowhead was 16.2 metres long.
The first baleen whale came after basilosaurus, which lived 35 to 40 million years ago. Basilosaurus was about 17 metres long.
Another early fossil was Morenocetus dating to 23 million years ago. Probably a close relative of the ancestor of the Bowhead whale. This was a baleen whale only about 5.5 metres long.
The new fossil on the link from 19 million years ago was about 9 metres long. A bit on the small side, but far from impossible.
I see the source of confusion, was the ancestor of the baleen whales about 17 metres long, 9 metres long, or about 6 metres long.