Re: In Lice, Clues to Human Origin and Attire

"richard01" <richardparker01@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 Verhaegen
http://allserv.rug.ac.be/~mvaneech/outthere.htm

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

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


.

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  • Re: In Lice, Clues to Human Origin and Attire
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