alphynix:Theme month time? Theme month time!So, let’s talk about whales. A group of mammals so highl
alphynix:Theme month time? Theme month time!So, let’s talk about whales. A group of mammals so highly adapted to aquatic life that some people still mistake them for fish. A group that includes some of the largest and most intelligent living creatures.Although their earliest evolutionary ancestors were a mystery until the late 1970s, today cetacean fossils make up one of the most striking examples of transitional forms. Combined with molecular analysis, we now know them to be descendants of early even-toed ungulates, with their closest living relatives being hippos.Every day this month I’ll be posting a new image highlighting points in whale evolution, from their terrestrial origins all the way through to modern times.Whalevolution Month #01 – IndohyusThis is Indohyus, a member of an extinct group of ungulates called raoellids – the closest known sister group to cetaceans. The very earliest whales probably looked similar to this, small hoofed creatures completely unrecognizable compared to their modern aquatic descendants.Around 60cm long (23.5in), Indohyus lived in what would become India and Pakistan about 50-48 million years ago. It had very dense bones similar to those of hippos, and probably led a semi-aquatic lifestyle comparable to modern water chevrotains, diving into water and remaining submerged to evade predators. But its main link to whales actually comes from its ear bones, with its skull showing evidence of a special structure called the involucrum. -- source link