Re: In Lice, Clues to Human Origin and Attire

On Mar 11, 10:11 am, "nickname" <alas_my_lo...@xxxxxxxxx> wrote:
On Mar 11, 7:53 am, "Marc Verhaegen" <fa204...@xxxxxxxxx> wrote:



"richard01" <richardparke...@xxxxxxxxx> wrote in message

news:1173534236.671638.64440@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Before speculating any further, try checking the actual dates
published in the small print of Tabe 1 of the paper:
http://www.biomedcentral.com/content/pdf/1741-7007-5-7.pdf

(I get "The page cannot be displayed". I'll try later again. What split is
Pediculus 10.63 Ma?)

Pediculus (3) 10.63 Ma (7.08-14.94)
Pthirus (1) 3.32 Ma (1.84-5.61) = H/G louse?
Ped.schaeffi & humanus (2) 6.39 Ma (3.94-9.96) = H/P louse
Pediculus & Pthirus (4) 12.95 Ma (9.42-17.38)
OWM/ape calibration 22.50 (20.13-24.87)
So they reckon they can be 95% sure that:
G & H Pthirus diverged ~ 1.84-5.61 Ma.
P & H Pediculus diverged ~ 3.94-9.96 Ma.
regards --Richard

Thanks a lot, Richard! Finally something sensible. :-) +-everything is
possible apparently. Some thoughts:

OWM/ape could have been considerably earlier than 22.5 Ma.

There were plenty of hominid spp ("hominid"=incl.HPG, everything after the
hominid/pongid split ~16-14 Ma) all over Africa from 9 to 0 Ma (Samburupith
9 Ma, Sahelanthr 7 Ma, Orrorin 6 Ma, Ardipith 5-4 Ma, lots of apiths 4-1
Ma), so if there was close contact (sex, food, nests...), louse hopping
could have occurred in all directions.

The paper says we could have got Pth. at any moment after ~5 Ma. If H/P=4
Ma (recent estimates), HP/G could be ~5 Ma, IOW, we can't even exclude that
we simply inherited Pth from the hominid (HPG) LCA (co-speciation HP/G &
H/G-Pth.).
Ped.hum./sch.~4-9 Ma coincides with the different estimates for H/P, so H &
P could well have inherited Ped. from the H/P LCA (co-speciation H/P &
H/P-Ped.).
IOW, simple co-speciations can't even excluded: G lost Ped. afterwards, P
lost Pth., H kept both. (Pth. then seems to have evolved slower than Ped.
Not unexpected if G looks more like the LCA than HP does. Samburupith was
rather G-like, but with thicker enamel.)
IOW, if H is more primitive in this respect (since H kept both lice), if we
simply assume that the HPG-LCA had scalp hair + Ped. & pubic hair + Pth.,
the problem is no problem anymore.

Only: why did G kept the pubic inhabitant? why P the scalp inhabitant? In
the HPG-LCA, both lice could have lived on body hair (Pth.=pubic &
Ped.=scalp+body, or else Pth.=pubic+body & Ped.=scalp), or (more likely IMO
in view of ape embryology) the HPG-LCA had no body hair, at least no
underfur (which would explain the Ped./Pth.split). Chimps have no pubic
hair AFAIK, so no wonder that P lost Pth. after H/P~5-4 Ma. Did G evolve
more "pubic"hair &/or less "scalp"hair after the HP/G split? Some chimps
have rel.long scalp hair (wavy?), but others (esp.old females) are bald. I
guess Pth.thrives more on curly hairs? What species of lice do orangs have?
Pth.? & gibbons & OWMs?

The Ped./Pth.split ~9-18 Ma might indicate when great apes lost their
underfur (or got naked) & the lice specialised in scalp & pubic hair. The
time apparently overlaps with the time when the apes crossed the Tethys...
:-)

--Marc Verhaegenhttp://allserv.rug.ac.be/~mvaneech/outthere.htm

http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Human_Evolution.html

http://groups.yahoo.com/group/AAT

The axillary/pubic/beard hair (in humans kinky, not wavy, straight, curly or frizzy) is the second most primitive condition, brought on by
testosterone in ancient mammals after the first lanugo (downy birth
fur) stage, but has been delayed in humans until puberty ("neoteny")
due to the extraordinary long nursing-weaning-learning curve. The
change from precocial to altricial offspring required this extended
delay and relates to nesting behaviour and dependence, varying effects
of aquatic influence and climate affected this. The 3rd stage of hair
is the typical (non-kinky) scalp, body and non-beard facial hair,
which is not testosterone-dependent (compared to kinky hair).

Female chimps go bald in their 3rd stage scalp hair, male humans also
do starting at puberty. Chimps lost their 2nd stage.

Gorillas generally don't go bald at their scalp, some males reduce
their stage 2 chest hair starting at puberty. Gorillas lost their 3rd
stage.

Humans haven't lost their 3 stages, but have greatly reduced them in
various degrees. Hylobatids probably retain all 3. Not sure about
orangs.

DD

I forgot to mention that sexual signaling in gorillas is strongly
scent-based, associated with 2nd stage hair, while in chimps (more so
bonobos) is strongly visual-based (estrus signs in post-puberty
females) associated with 3rd stage. This indicates that Pan has left
the tidal influence for a longer time, living near freshwater upstream
areas (no submersion, no immersion, some shallow wading), while
gorillas remained tidally-effected until more recently (no submersion,
some immersion), both salt excretion.
Both humans and orangs have estrus cycles correlative to tidal cycles,
orangs are known to shallow wade (no submersion, no immersion)
indicating past association with coasts. Orangs have visual sexual
signalling, paralleling bonobos, so they have 3rd stage. I guess.

Not certain how this fits with lice yet.

DD


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