https://www.nature.com/articles/ncomms9431
The hand of H.naledi is very similar to that of
modern humans, with two major differences:
a) it has an extraordinarily long and powerful
thumb;
b) Its fingers are curved, like those of
australopiths, but otherwise resemble those
of modern humans.
Anyone want to suggest likely reasons?
I've changed my views on this a couple of
times, and will probably modify them again
before posting here.
https://www.nature.com/articles/ncomms9431
The hand of H.naledi is very similar to that of
modern humans, with two major differences:
a) it has an extraordinarily long and powerful
thumb;
b) Its fingers are curved, like those of
australopiths, but otherwise resemble those
of modern humans.
Anyone want to suggest likely reasons?
I've changed my views on this a couple of
times, and will probably modify them again
before posting here.
https://www.nature.com/articles/ncomms9431
The hand of H.naledi is very similar to that of
modern humans, with two major differences:
a) it has an extraordinarily long and powerful
thumb;
b) Its fingers are curved, like those of
australopiths, but otherwise resemble those
of modern humans.
Anyone want to suggest likely reasons?
I've changed my views on this a couple of
times, and will probably modify them again
before posting here.
https://www.nature.com/articles/ncomms9431
The hand of H.naledi is very similar to that of
modern humans, with two major differences:
a) it has an extraordinarily long and powerful
thumb;
b) Its fingers are curved, like those of
australopiths, but otherwise resemble those
of modern humans.
Anyone want to suggest likely reasons?
Already in the paper.
On Friday, February 11, 2022 at 9:58:49 AM UTC, Pandora wrote:
https://www.nature.com/articles/ncomms9431
The hand of H.naledi is very similar to that of
modern humans, with two major differences:
a) it has an extraordinarily long and powerful
thumb;
b) Its fingers are curved, like those of
australopiths, but otherwise resemble those
of modern humans.
Anyone want to suggest likely reasons?
Already in the paper.Not so. Or not in any meaningful manner:
This is typical of the technically detailed
verbiage, which lacks all sense of purpose
(What were these hands FOR . . ?) :
"This distinctive mosaic of morphology has yet to be observed
in any other hominin taxon and suggests the use of the hand
for arboreal locomotion in combination with forceful precision
manipulation typically used during tool-related behaviours."
Firstly, the 'arboreal locomotion' doesn't
apply since that's the norm for other
primates and their hands invariably have
long thin fingers.
Secondly, they appear to have lived in
dolomitic caves, and few trees grow on
their surface landscapes -- certainly no
large ones, and no forests. So it's hard
to see that they'd have much need for
'arboreal locomotion'.
Thirdly, if any hominin had a need for
'forceful precision manipulation typically
used during tool-related behaviours', it
would be later and bigger ones, especially
humans and neanderthals. But naledi's
thumb is (proportionately) much longer
and stronger than any seen later or
elsewhere.
" . . The H. naledi pollical distal phalanx (n=2) is large and robust"
Why?
On Friday, February 11, 2022 at 9:58:49 AM UTC, Pandora wrote:
https://www.nature.com/articles/ncomms9431
The hand of H.naledi is very similar to that of
modern humans, with two major differences:
a) it has an extraordinarily long and powerful
thumb;
b) Its fingers are curved, like those of
australopiths, but otherwise resemble those
of modern humans.
Anyone want to suggest likely reasons?
Already in the paper.
Not so. Or not in any meaningful manner:
This is typical of the technically detailed
verbiage, which lacks all sense of purpose
(What were these hands FOR . . ?) :
"This distinctive mosaic of morphology has yet to be observed
in any other hominin taxon and suggests the use of the hand
for arboreal locomotion in combination with forceful precision
manipulation typically used during tool-related behaviours."
Firstly, the 'arboreal locomotion' doesn't
apply since that's the norm for other
primates and their hands invariably have
long thin fingers.
Secondly, they appear to have lived in
dolomitic caves, and few trees grow on
their surface landscapes -- certainly no
large ones, and no forests. So it's hard
to see that they'd have much need for
'arboreal locomotion'.
Thirdly, if any hominin had a need for
'forceful precision manipulation typically
used during tool-related behaviours', it
would be later and bigger ones, especially
humans and neanderthals. But naledi's
thumb is (proportionately) much longer
and stronger than any seen later or
elsewhere.
" . . The H. naledi pollical distal phalanx (n=2) is large and robust"
Why?
Already in the paper.
Not so. Or not in any meaningful manner:
This is typical of the technically detailed
verbiage, which lacks all sense of purpose
It's thoroughly empirical, comparative and functional anatomy.
Apparently way above your level of expertise and comprehension.
Where and when did you study primate functional anatomy?
(What were these hands FOR . . ?) :
It says right here:
"This distinctive mosaic of morphology has yet to be observed
in any other hominin taxon and suggests the use of the hand
for arboreal locomotion in combination with forceful precision
manipulation typically used during tool-related behaviours."
Firstly, the 'arboreal locomotion' doesn't
apply since that's the norm for other
primates and their hands invariably have
long thin fingers.
But "forceful precision manipulation typically used during
tool-related behaviours" is not typical of primates. That's where the
mosaic morphology comes into view, because you can't do that with long
thin fingers and a short thumb.
Secondly, they appear to have lived in
dolomitic caves, and few trees grow on
their surface landscapes -- certainly no
large ones, and no forests. So it's hard
to see that they'd have much need for
'arboreal locomotion'.
And don't recall any reconstruction of the paleoenvronment of Homo
naledi outside their depositional environment.
Thirdly, if any hominin had a need for
'forceful precision manipulation typically
used during tool-related behaviours', it
would be later and bigger ones, especially
humans and neanderthals. But naledi's
thumb is (proportionately) much longer
and stronger than any seen later or
elsewhere.
" . . The H. naledi pollical distal phalanx (n=2) is large and robust"
As far as I can see from fig.2 in Kivell et al. relative thumb length
in H. naledi falls within the range of modern male Homo sapiens, and
is shorter than in Australopithecus sediba (2mya). https://www.nature.com/articles/ncomms9431/figures/2
The same figure also shows that the most obvious difference is between hominins and Pan/Gorilla, not among hominins.
On Sunday, February 13, 2022 at 3:46:47 PM UTC, Pandora wrote:
Already in the paper.
Not so. Or not in any meaningful manner:
This is typical of the technically detailed
verbiage, which lacks all sense of purpose
It's thoroughly empirical, comparative and functional anatomy.
Apparently way above your level of expertise and comprehension.
Where and when did you study primate functional anatomy?
Standard PA's 'level of expertise and
comprehension" can be judged from
their routine 'assessment' that the
curvature of hominin fingers before
homo came from arboreal behaviour,
in particular sleeping in trees!
If they
had slept in trees, they'd have been
in them for more than 12 hours out
of 24, and required much the same
kinds of hands as those hominoids
that really do spend most of their
time in trees -- e.g. chimps.
Secondly, they appear to have lived in
dolomitic caves, and few trees grow on
their surface landscapes -- certainly no
large ones, and no forests. So it's hard
to see that they'd have much need for
'arboreal locomotion'.
And don't recall any reconstruction of the paleoenvronment of Homo
naledi outside their depositional environment.
The geomorphology of dolomitic limestone
is very stable: little or no water on the
surface; trees only in those isolated places
where the roots can reach down into
openings to get water -- usually where a
cave roof has collapsed.
It seems unlikely that there was open
water (or significant food resources) within
5-6 km of the Dinaledi chamber. Yet the
corpses were hardly carried that far,
suggesting that the group/tribe/family
resided in it, or in nearby caves, travelling
several km for daily foraging.
Thirdly, if any hominin had a need for
'forceful precision manipulation typically
used during tool-related behaviours', it
would be later and bigger ones, especially
humans and neanderthals. But naledi's
thumb is (proportionately) much longer
and stronger than any seen later or
elsewhere.
" . . The H. naledi pollical distal phalanx (n=2) is large and robust"
As far as I can see from fig.2 in Kivell et al. relative thumb length
in H. naledi falls within the range of modern male Homo sapiens, and
is shorter than in Australopithecus sediba (2mya).
https://www.nature.com/articles/ncomms9431/figures/2
It's around the 98th percentile -- not
usually describable as 'within the range'.
Modern male human hands are highly
variable, in size and shape. The paper
suggests that -- in this measure -- the
hands of h.naledi were all much the
same:
" . . The base and proximal articular facet of the pollical
metacarpal are remarkably small relative to its length,
both radioulnarly and dorsopalmarly in Hand 1 and in
the six additional pollical metacarpals . ."
The same figure also shows that the most obvious difference is between
hominins and Pan/Gorilla, not among hominins.
Of course. And since PA has got almost
nowhere in explaining the differences
between hominins and pan/gorilla, it
would be foolish to think it could do
anything with intra-hominin variations.
And this is confirmed by the rest of the upper limb morphology, such
as a markedly cranially-oriented glenoid fossa and very oblique
scapular spine, reflecting the habitually overhead posture of the arm
in suspensory behaviour to assist with efficient arm elevation: https://www.sciencedirect.com/science/article/abs/pii/S004724841630135X
If they
had slept in trees, they'd have been
in them for more than 12 hours out
of 24, and required much the same
kinds of hands as those hominoids
that really do spend most of their
time in trees -- e.g. chimps.
Chimps also use their hands in terrestrial locomotion and much less
for forceful precision manipulation. You get different kinds of
trade-off.
It seems unlikely that there was open
water (or significant food resources) within
5-6 km of the Dinaledi chamber. Yet the
corpses were hardly carried that far,
suggesting that the group/tribe/family
resided in it, or in nearby caves, travelling
several km for daily foraging.
The many cercopithecids at sites such as Sterkfontein and Swartkrans
indicate a significant arboreal component, while the valley bottom may
have retained standing water year-round, supporting more extensive
tree cover.
I'm sure you have a fantastic idea about hand function in H. naledi,
on the same level as marine hominins. Or is it just rock climbing with
ropes and anchors?
Homo did not spring from nowhere.
Its ancestors swung in trees. There
have been no strong selective forces
that would have displaced this
anatomy
https://www.nature.com/articles/ncomms9431
The hand of H.naledi is very similar to that of
modern humans, with 2 major differences:
a) it has an extraordinarily long & powerful thumb;
b) Its fingers are curved cf australopiths, but otherwise resemble Hs.
Anyone want to suggest likely reasons?
I've changed my views on this a couple of
times, and will probably modify them again
before posting here.
Pauli, Pauli, just google "Australopithecus naledi PPT".
Our hands are generally more primitive than those of P or G:
no knuckle-walking:
KWing evolved lately in parallel in P // G.
IOW, naledi was Pan naledi, fossil subgenus Australopithecus,
google "ape human evolution made easy PPT Verhaegen".
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