Posts Tagged ‘palaeontogy’
How bizarre is Homo naledi?
The ‘Leti skull’, an infant H naledi found in the Rising Star cave system
I’ve listened here and there, now and then, to the Homo naledi story without ever fully taking it in – and maybe nobody can. A species based on specimens that are only found deep in a near-inaccessible underground cave-thing, specimens suggesting a rather primitive species considering the time-span – about 335,000 to 235,000 years ago (Middle Pleistocene, I must remember). Were they the last of a species that dates back quite a bit further, and WTF happened for their remains to be found in such a bizarre underground space (15 specimens, of all ages, were found in the Dinaledi cave of the complex Rising Star system, and two or three more in the nearby Lesedi cave)? No specimens of the same type appear to have been found above ground – what’s the story there? Did they fall or were they pushed? Were they already dead?
Of course the story of our ancestors and ancient cousins has become more complex and intriguing in recent times, with H floresiensis, and the H longi-Denisovan discovery or question or whatever, and the Jebel Irhoud fossils. Is it a great time to be a palaeontologist, or just too headache-inducing? There are certainly lots of whats and wheres, so I’ll try to confine myself to the title topic.
No H naledi specimens have been found elsewhere. Were the caves just an excellent preservation site? And the number of specimens does seem to suggest deliberate placement or disposal after death. Anyway, this species was designated Homo in spite of a cranial capacity less than half that of H sapiens, size not being everything (H floresiensis, and crows). I’m going through the lengthy Wikipedia article and still finding more questions than answers. The claim in the first published accounts of some kind of deliberate burial or at least placement of bodies into the main cavern (Dinaledi) appears to have been debunked, but there doesn’t seem to be much in the way of alternative explanations either. Lots of the same species falling down this narrow shaft at different times? Was the topography of the area – if that’s the word – quite different a couple of hundred thousand years ago?
What’s most interesting – and frustrating – is that this diminutive yet relatively modern species – not subject to island dwarfism – was wandering around among other human types at that time. Or was it? The oldest H sapiens remains were found in Morocco, a world away from the Rising Star cave system. There is the ‘Florisbad skull’, found near Bloemfontein, the dating of which puts it in the same time-frame as H naledi, and which Chris Stringer considers to be early H sapiens, so… it seems there are tantalising, fragmentary finds. The whole picture of early humans, what with new fossil discoveries, new dating techniques, and the argy-bargy of lumpers and splitters, continues to fascinate and complexify. It’s all good fun.
References
https://australian.museum/learn/science/human-evolution/homo-naledi/