Homo naledi, a New Species of the Genus Homo

[Drakkith]

Just saw an article on this on facebook:

Abstract
Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa.

Full article here: http://elifesciences.org/content/4/e09560

Related article titled: Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa : http://elifesciences.org/content/4/e09561

Estimated age of the bones is between 2 and 3 million years, and all of the remains were found in a single 'burial' chamber, according to the IFL article I read. This apparently represents the only known occurrence of a species other than our own deliberately and repeatedly burying its dead in a protected area, away from the external environment.

Article from IFL: http://www.iflscience.com/editors-blog/newly-discovered-human-ancestor-likely-ritualistically-disposed-its-dead

NY Times Article: http://www.nytimes.com/2015/09/11/s...-species-human-ancestor-homo-naledi.html?_r=0

Short video from Professor Lee Berger explaining some basics of the species:

 

[Drakkith]

One question I have is how are these types of fossils usually dated? They were discovered two years ago. Is that not enough time to date them?

 

[Bystander]

how are these types of fossils usually dated?

Stratigraphy. That said, from the description of the site, stratigraphy inside a deep cave system is going to be tough; might be able to compare pollen and dust with lake sediments in the immediate vicinity.

 

[Drakkith]

So no radioactive dating or something then?

 

[Bystander]

¹⁴C is no good beyond ~ 60 ka, and there's no reservoir of bio-active elements with100 ka to 10 Ma half-lives to be incorporated into growing organisms.

 

[DiracPool]

What typically happens is that they'll mix stratigraphics with radiometric dating of the accompanying soil. This is what they did with Ardipithecus and Lucy, using the accompanying volcanic ash to do the radiometric dating.From: https://en.wikipedia.org/wiki/Radiometric_dating
"Together with stratigraphic principles, radiometric dating methods are used in geochronology to establish the geological time scale"

From: https://en.wikipedia.org/wiki/Geochronology
"Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves"

From:
https://en.wikipedia.org/wiki/Ardipithecus
"The first fossil found was dated to 4.4 million years ago on the basis of its stratigraphic position between two volcanic strata: the basal Gaala Tuff Complex (GATC) and the Daam Aatu Basaltic Tuff (DABT)"

and:

"Radiometric dating of the layers of volcanic ash encasing the deposits suggest that Ardi lived about 4.4 million years ago"

Also, from: https://en.wikipedia.org/wiki/Lucy_(Australopithecus)
"The Lucy fossil was dated reliably in 1990–1992 by applying the argon-argon radiometric dating method to the volcanic ash surrounding it."

 

[Jupiter60]

Apparently that species homo naledi they think it might have buried its dead. Something previously thought that only Homo Sapiens and Neanderthals did.

 

[jim mcnamara]

Well,
http://www.pnas.org/content/109/6/1889.full

seems to indicate Neanderthals buried their dead and use red ochre as part of the burial ritual. Red ochre, which was not native to the site, has definitely been found with H. neanderthalensis fossils.

 

[Graeme M]

I just read the Nat Geo article on this and also quickly browsed the paper in elifesciences and was blown away by the whole thing. I'd heard mention on TV recently but hadn't paid it much attention. The description of the mix of primitive and modern features is especially intriguing. The braincase is so very small yet there is suggestions of modern behaviour and I saw a brief mention in the Nat Geo article re the discovery of stone tools from 3.3 million years ago, what might that say about the lineage. I really look forward to hearing more about dating this new species. I understand from the Nat Geo article that the fossils were pretty much found just lying on the cave floor so not sure how dating can be achieved?

 

[Drakkith]

I understand from the Nat Geo article that the fossils were pretty much found just lying on the cave floor so not sure how dating can be achieved?

Not sure. That may be one reason that they haven't been accurately dated yet.