Fossils Point to Multiple ‘Homo’ Species

Fossil Questions if Our Ancestors Had Cousins

There exists a fossil of a human skull, labelled 1470, which has been at the center of quite a bit of controversy since its discovery in 1972. This fossil, said to be from 2 million years ago, was different enough from the existing human ancestor at that period—Homo erectus—for some scientists to propose that it belonged to a new species. And thus were formed two warring camps. One said that 1470 belonged to Homo erectus, and the difference could be accounted for by variation within a species. The other camp believed that 1470 represented a remnant of a new species that might have existed along with Homo erectus, meaning that the lineage of current humans might not be as linear as we think it is.

A timeline in Homo sapiens evolution. Homo rudolfensis is the contested species which might have co-existed with two others.
A timeline in Homo sapiens evolution. Homo rudolfensis is the contested species which might have co-existed with two others. [Image Credit: Nature]

Now, the discovery of three new fossils has strengthened the claims of the second camp. These were discovered by a team led by Meave Leakey (who was also involved in discovering 1470) also near Lake Turkana in Kenya. The new fossils, which are from 1.78 to .95 million years ago, resemble fossil 1470 in skull structure by having similarly large and flat faces. Scientists are saying that the presence of more than a single outlier suggests that 1470 wasn’t just an unusual case in the species Homo erectus, but just one among a number of individuals in an altogether new species, which they are calling Homo rudolfensis. This finding contradicts the belief that our species evolved from the ancestors we share with apes in a strictly linear progression. The authors of this research believe that 3 species existed simultaneously—erectus, 1470 and a third branch— of which erectus eventually evolved to become Homo sapiens.

Not Definitive Evidence

This discovery isn’t convincing the critics, though, who think the evidence is not definite, and that the three fossils could still be diverse members of the same species. For now, our family tree remains murky.

You can unearth more information about this research here and here.

Found: World’s Smallest Mammoth Was Barely The Size Of A Baby Elephant!

They were furry and cute; they were also mammoths. A group of animals are believed to have roamed the island of Crete a long time ago. Their remains had been discovered a century ago, but only a recent discovery settles the debate about the size of the animals.\

Much smaller?

It turns out that the adults of the species were the size of a modern elephant calf, making it just a meter of so tall – even less than the average height of humans. The discovery instrumental in making this conclusion is a collection of teeth from the animals that lay scattered all over the island.

The crucial discovery

Dwarfism – the evolutionary basis

Evolutionary scientists call this dwarfism. The animal lineage suddenly undergoes a shrinkage in the size of its individual due to certain environmental factors. Dwarfism is particularly pronounced in island environments. Scarcity of food is the primary cause. Insular location also prevents vast migrations of animal species, as can be often seen in animal herds on landmasses.

Another factor contributing to the reduction in size is the lack of predators. If you don’t need size to fend off predators, you’re probably better off smaller, as it takes much less maintenance.

So, while their cousins on the landmass enlarged in size, the insular individuals became smaller. Just insular dwarfism taken to the extreme.

Not the woolly mammoths

It should be noted that these animals were not woolly mammoths, like the imagination conjures up. These were mammoths suited to warmer climates, and the temperatures in Crete never dipped very low.

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