I've no argument with Hardy's 20ma and Filler's date of ~20ma as initial aquatic
era, in an evolutionary sense. Upright posture, proconsul/morotopith wetland
sit-float-feeding as a change from its predecessor of upright dry sitting
(geladas) indicates daily aquatic foraging (surface feeding with gradually
enlarging air sacs and shrinking tail, maintained even in today's lowland
Homo Genus 5ma developing estuarine submersion foraging (crouch plucking), 3ma
seashore diving, 1.5ma diving/backfloating ARC cycle around the Levant and
former peri/tethys and upper Rift, gradual increase in waterside group ambush
improved tool technologies, which eventually took them to cooler rougher
predator-filled waters where rafts and boats were advantageous.
This from PZ's blog:
"As usual, it starts on a sound foundation of confirmed, known evidence, makes a reasonably hypothesis on the basis of the facts, and then proposes a series of research avenues with predicted results that would confirm the idea."
Non-scientists take note: this is a category of paper that is usually titled "hypothesis" or "insight," as opposed to a peer-reviewed research paper or a literature review, although it is more similar to the latter. PLoS Biology uses the term "unsolved mystery:"
Unsolved Mysteries discuss a topic of biological importance that is poorly understood and in need of research attention.-
Re: From sit-float-feeding to backfloat-dive-feeding to boat-net-feeding
PAs can argue forever about details when evidence is scattered and lacking, and
topography and climate changes at varying rates.
I've produced a simple explanation, of how hominoids differentiated from other
primates (tail loss, air sacs), how Homo differentiated from other hominids (ARC
diving, low UV saltwater backfloating), and how Homo sapiens differentiated from
other Homo (mass harvesting -> trade -> transport).
Of the question 'What happened?' the missing pieces of the puzzle have been
found and placed, they fit.
Other explanations for the unique characteristics of humans compared to our genetic kin fall short by not taking into account various behaviors and vestigial traits common to humans but not to other primates. That doesn't mean they are insignificant or incorrect, just incomplete.
The story is a bit more complete now.
Prose of human speciation
Hominoids vs other primates (sit/float/eat, tail loss, air sacs),
Homo vs other hominids (ARC diving, low UV saltwater backfloating),
Homo sapiens vs other Homo (mass harvesting/transport).
Hominoids sit/floating on flooded ground,
hands to pluck/peel/pull/pinch,
calls/splashes/thumps to warn,
sleep in tree hollows, forks (damp), beaver dens
eat meat without bones (eggs, pith, larvae, seeded fruit)
Homo going deeper into water/caves, while apes went higher,
Homo crafted long/sharp fangs/claws of sticks/stones/shells.
Using pebbles to crack, flakes to cut, bifacials to bait, branches to bash,
spears to probe/pry/poke, lords of the ring/pond/pool
eat meat/nuts with shells/bones to be removed and reused.
Hs brought sunlight into cold night (fire),
and dark into hot day (shelter), and wet into dry.
Bags/baskets/boats processed (cut, woven) to transport, harpoons/atlatls to
Meats/grains to guide/process (planting/herding), grinding masses, soaking,
heating, storing, exchanging, comparing.
Rings concentrically ordered, become overly congested and condense into
rectilinear patterns and vertical double-storied dwellings and overlapped social
groupings and finally oral-named individuals become anonymously writ-numbered
cells in the spherical body of humankind and beyond.
Compare these two shelters: entry routes, protection from bears/cold
Mammoth bone lodge of Central Russian floodplain 15ka, summer doorway
22ka camp huts & bedding at upper Rift waterside link
seal ancestors link