Hacker News Reader

Comment by kypro | Hacker News Reader

How is it possible to indentify a new species from just a skull fragment and jawbone? Would there need to be multiple similar bones to rule out the possiblity of a genetic outlier? And even then it's not like there isn't fairly significant variance in bone structure between different populations of human today. Can we really say from two bits of bone that it's a different species?

I have no knowledge of anthropology but it just seems a bit crazy to me that from few bits of bone we can declare we found a new species.

View on HN

The teeth and jaw are actually one of the most distinctive parts of a skeleton - so it's not totally crazy. The shape of the teeth and size of the jaw muscles could easily identify something as being not modern human. But the article gave 0 evidence for why they believe it to be a new species, so I'm not convinced either.

The research was published in Science. If you want their evidence, look at where they actually published it.

This isn't a criminal trial, with failsafe rules about doubt.

There are very few generic outliers. They do exist, but at the same time, the chance that the next person you meet will be <1.20m or >2.40m tall is insignificant.

The argument is stronger for the past, because generic outliers tend to have worse health than the average and have worse chances of reaching adulthood, so if you find a part of the skeleton of a single adult, the chance that it's someone who's half/twice as tall as the rest of the population is even smaller than for today.

https://www.mindprod.com/image/math/livinghistogram.jpg shows an entire class. They could have had a generic outlier among the pupils, but most people are near the average, see?

But the same logic applies. Instead of innocent until proven guilty it's "not a new species" until there's sufficient evidence to establish that.

I'm dubious that they have that evidence, especially given their further unsubstantiated claims that they're ancestors of the neanderthals. The linked article discussed 0 evidence for why it's a new species. Presumably there's a published paper that goes into details.

It's a new discovery in science, which means it will be about 10 years before we know if it's 90% correct or not. Probably need to wait a year to rule out simple measurement errors.

To some degree if a scientific discovery is news, it isn't firmly established, because if the entire field hasn't heard about it, it hasn't been properly vetted.

Indeed, the worst place to learn about scientific breakthroughs is in the news media, as there is an inherent interest to emphasize the newsworthiness of the result rather than letting the scientific community digest, reproduce, and integrate the finding into the overall state of the art, which is a slow process that doesn't show up in headlines.

OK, so what's sufficient evidence?

You're "dubious that they have that evidence". What evidence is required, in your opinion, then?

Speaking as a layman, my first guess at a suitable threshold would be: finding a large-enough, different-enough part of a skeleton/whatever that in the past such parts have seldom turned out to be an existing species.

Humans being less than 1.2m tall is extremely common, and I will bet there was a significant period of your own life in which that criterion applied to you.

(edit: and you should not be surprised at the number of "new species" which are just juveniles of a known species.)

>> Humans being less than 1.2m tall is extremely common, and I will bet there was a significant period of your own life in which that criterion applied to you.

And how where their teeth at the time?

Stature or size of teeth is really not a good measurement, especially to declare a new species!

Humans come in various shapes and sizes. In fact, given that the remains were found in a sinkhole, small stature might have something to do with their inability to escape.

For example, "little people" have adult teeth:

https://www.lpaonline.org/

Also, there are several types of common, modern humans that then to have very short statures.

https://en.wikipedia.org/wiki/Pygmy_peoples

On the other end of the scale,

https://stillunfold.com/people/10-real-life-giants-known-for...

When I was in school, one of our midterms for wildlife biology was to take a tooth or some bone fragments and describe as much as we could about the animal's habitat, food sources, overall health before death, roughly how old the animal was and a bunch of other things.

It's actually surprising how much information a single tooth or piece of bone can actually give you.

How would you know if you were correct?

The teachers who marked us knew where the specimens came from...

> How is it possible to indentify a new species...

I'd love that ELI5.

If it's just morphology and traits, given the amazing variety of people alive today, I wonder how many different species future archaeologists would identify.

I've seen the array of skulls at the natural history museum. Clear progression, sure. But when does one thing become another thing.

I know, I know, dividing lines are arbitrary. But I'd still like the ELI5 for how a professional knows homo sapiens vs neanderthal. Maybe a visual diff tool.

Some scientists also like to generate buzz because that's sometimes the only way to get financing. But having this apparently unique piece of evidence and calling it "one of the last survivors" of the new species (as opposed to one of the first, or squarely in the middle) gives away that for now it's just a flashy assumption.

Not to mention that the word "survivor" is completely meaningless for this dead ancient humanoid

Reply on news.ycombinator.com